diff --git a/common/group.ts b/common/group.ts
index 181ad153..5c716dba 100644
--- a/common/group.ts
+++ b/common/group.ts
@@ -6,14 +6,16 @@ export type Group = {
   creatorId: string // User id
   createdTime: number
   mostRecentActivityTime: number
-  memberIds: string[] // User ids
   anyoneCanJoin: boolean
-  contractIds: string[]
-
+  totalContracts: number
+  totalMembers: number
   aboutPostId?: string
   chatDisabled?: boolean
-  mostRecentChatActivityTime?: number
   mostRecentContractAddedTime?: number
+  /** @deprecated - members and contracts now stored as subcollections*/
+  memberIds?: string[] // Deprecated
+  /** @deprecated - members and contracts now stored as subcollections*/
+  contractIds?: string[] // Deprecated
 }
 export const MAX_GROUP_NAME_LENGTH = 75
 export const MAX_ABOUT_LENGTH = 140
diff --git a/firestore.rules b/firestore.rules
index e42e3ed7..15b60d0f 100644
--- a/firestore.rules
+++ b/firestore.rules
@@ -160,25 +160,40 @@ service cloud.firestore {
                                                                     .hasOnly(['isSeen', 'viewTime']);
     }
 
-     match /groups/{groupId} {
+    match /{somePath=**}/groupMembers/{memberId} {
+      allow read;
+    }
+
+    match /{somePath=**}/groupContracts/{contractId} {
+      allow read;
+    }
+
+	   match /groups/{groupId} {
           allow read;
           allow update: if (request.auth.uid == resource.data.creatorId || isAdmin())
                            && request.resource.data.diff(resource.data)
                            .affectedKeys()
-                           .hasOnly(['name', 'about', 'contractIds', 'memberIds', 'anyoneCanJoin', 'aboutPostId' ]);
-         allow update: if (request.auth.uid in resource.data.memberIds  || resource.data.anyoneCanJoin)
-                           && request.resource.data.diff(resource.data)
-                           .affectedKeys()
-                           .hasOnly([ 'contractIds', 'memberIds' ]);
+                           .hasOnly(['name', 'about', 'anyoneCanJoin', 'aboutPostId' ]);
           allow delete: if request.auth.uid == resource.data.creatorId;
 
-          function isMember() {
-            return request.auth.uid in get(/databases/$(database)/documents/groups/$(groupId)).data.memberIds;
+          match /groupContracts/{contractId} {
+              allow write: if isGroupMember() || request.auth.uid == get(/databases/$(database)/documents/groups/$(groupId)).data.creatorId
+            }
+
+          match /groupMembers/{memberId}{
+             allow create: if request.auth.uid == get(/databases/$(database)/documents/groups/$(groupId)).data.creatorId || (request.auth.uid == request.resource.data.userId && get(/databases/$(database)/documents/groups/$(groupId)).data.anyoneCanJoin);
+             allow delete: if request.auth.uid == resource.data.userId;
+            }
+
+          function isGroupMember() {
+            return exists(/databases/$(database)/documents/groups/$(groupId)/groupMembers/$(request.auth.uid));
           }
+
           match /comments/{commentId} {
           	allow read;
-            allow create: if request.auth != null && commentMatchesUser(request.auth.uid, request.resource.data) && isMember();
+            allow create: if request.auth != null && commentMatchesUser(request.auth.uid, request.resource.data) && isGroupMember();
           }
+
         }
 
       match /posts/{postId} {
diff --git a/functions/src/create-group.ts b/functions/src/create-group.ts
index 71c6bd64..fc64aeff 100644
--- a/functions/src/create-group.ts
+++ b/functions/src/create-group.ts
@@ -58,13 +58,23 @@ export const creategroup = newEndpoint({}, async (req, auth) => {
     createdTime: Date.now(),
     mostRecentActivityTime: Date.now(),
     // TODO: allow users to add contract ids on group creation
-    contractIds: [],
     anyoneCanJoin,
-    memberIds,
+    totalContracts: 0,
+    totalMembers: memberIds.length,
   }
 
   await groupRef.create(group)
 
+  // create a GroupMemberDoc for each member
+  await Promise.all(
+    memberIds.map((memberId) =>
+      groupRef.collection('groupMembers').doc(memberId).create({
+        userId: memberId,
+        createdTime: Date.now(),
+      })
+    )
+  )
+
   return { status: 'success', group: group }
 })
 
diff --git a/functions/src/create-market.ts b/functions/src/create-market.ts
index e9804f90..300d91f2 100644
--- a/functions/src/create-market.ts
+++ b/functions/src/create-market.ts
@@ -155,8 +155,14 @@ export const createmarket = newEndpoint({}, async (req, auth) => {
     }
 
     group = groupDoc.data() as Group
+    const groupMembersSnap = await firestore
+      .collection(`groups/${groupId}/groupMembers`)
+      .get()
+    const groupMemberDocs = groupMembersSnap.docs.map(
+      (doc) => doc.data() as { userId: string; createdTime: number }
+    )
     if (
-      !group.memberIds.includes(user.id) &&
+      !groupMemberDocs.map((m) => m.userId).includes(user.id) &&
       !group.anyoneCanJoin &&
       group.creatorId !== user.id
     ) {
@@ -227,11 +233,20 @@ export const createmarket = newEndpoint({}, async (req, auth) => {
   await contractRef.create(contract)
 
   if (group != null) {
-    if (!group.contractIds.includes(contractRef.id)) {
+    const groupContractsSnap = await firestore
+      .collection(`groups/${groupId}/groupContracts`)
+      .get()
+    const groupContracts = groupContractsSnap.docs.map(
+      (doc) => doc.data() as { contractId: string; createdTime: number }
+    )
+    if (!groupContracts.map((c) => c.contractId).includes(contractRef.id)) {
       await createGroupLinks(group, [contractRef.id], auth.uid)
-      const groupDocRef = firestore.collection('groups').doc(group.id)
-      groupDocRef.update({
-        contractIds: uniq([...group.contractIds, contractRef.id]),
+      const groupContractRef = firestore
+        .collection(`groups/${groupId}/groupContracts`)
+        .doc(contract.id)
+      await groupContractRef.set({
+        contractId: contract.id,
+        createdTime: Date.now(),
       })
     }
   }
diff --git a/functions/src/create-user.ts b/functions/src/create-user.ts
index 35394e90..eabe0fd0 100644
--- a/functions/src/create-user.ts
+++ b/functions/src/create-user.ts
@@ -1,6 +1,5 @@
 import * as admin from 'firebase-admin'
 import { z } from 'zod'
-import { uniq } from 'lodash'
 
 import { PrivateUser, User } from '../../common/user'
 import { getUser, getUserByUsername, getValues } from './utils'
@@ -17,7 +16,7 @@ import {
 
 import { track } from './analytics'
 import { APIError, newEndpoint, validate } from './api'
-import { Group, NEW_USER_GROUP_SLUGS } from '../../common/group'
+import { Group } from '../../common/group'
 import { SUS_STARTING_BALANCE, STARTING_BALANCE } from '../../common/economy'
 
 const bodySchema = z.object({
@@ -117,23 +116,8 @@ const addUserToDefaultGroups = async (user: User) => {
       firestore.collection('groups').where('slug', '==', slug)
     )
     await firestore
-      .collection('groups')
-      .doc(groups[0].id)
-      .update({
-        memberIds: uniq(groups[0].memberIds.concat(user.id)),
-      })
-  }
-
-  for (const slug of NEW_USER_GROUP_SLUGS) {
-    const groups = await getValues<Group>(
-      firestore.collection('groups').where('slug', '==', slug)
-    )
-    const group = groups[0]
-    await firestore
-      .collection('groups')
-      .doc(group.id)
-      .update({
-        memberIds: uniq(group.memberIds.concat(user.id)),
-      })
+      .collection(`groups/${groups[0].id}/groupMembers`)
+      .doc(user.id)
+      .set({ userId: user.id, createdTime: Date.now() })
   }
 }
diff --git a/functions/src/index.ts b/functions/src/index.ts
index 9a5ec872..be73b6af 100644
--- a/functions/src/index.ts
+++ b/functions/src/index.ts
@@ -21,9 +21,7 @@ export * from './on-follow-user'
 export * from './on-unfollow-user'
 export * from './on-create-liquidity-provision'
 export * from './on-update-group'
-export * from './on-create-group'
 export * from './on-update-user'
-export * from './on-create-comment-on-group'
 export * from './on-create-txn'
 export * from './on-delete-group'
 export * from './score-contracts'
diff --git a/functions/src/on-create-comment-on-group.ts b/functions/src/on-create-comment-on-group.ts
deleted file mode 100644
index 15f2bbc1..00000000
--- a/functions/src/on-create-comment-on-group.ts
+++ /dev/null
@@ -1,46 +0,0 @@
-import * as functions from 'firebase-functions'
-import { GroupComment } from '../../common/comment'
-import * as admin from 'firebase-admin'
-import { Group } from '../../common/group'
-import { User } from '../../common/user'
-import { createGroupCommentNotification } from './create-notification'
-const firestore = admin.firestore()
-
-export const onCreateCommentOnGroup = functions.firestore
-  .document('groups/{groupId}/comments/{commentId}')
-  .onCreate(async (change, context) => {
-    const { eventId } = context
-    const { groupId } = context.params as {
-      groupId: string
-    }
-
-    const comment = change.data() as GroupComment
-    const creatorSnapshot = await firestore
-      .collection('users')
-      .doc(comment.userId)
-      .get()
-    if (!creatorSnapshot.exists) throw new Error('Could not find user')
-
-    const groupSnapshot = await firestore
-      .collection('groups')
-      .doc(groupId)
-      .get()
-    if (!groupSnapshot.exists) throw new Error('Could not find group')
-
-    const group = groupSnapshot.data() as Group
-    await firestore.collection('groups').doc(groupId).update({
-      mostRecentChatActivityTime: comment.createdTime,
-    })
-
-    await Promise.all(
-      group.memberIds.map(async (memberId) => {
-        return await createGroupCommentNotification(
-          creatorSnapshot.data() as User,
-          memberId,
-          comment,
-          group,
-          eventId
-        )
-      })
-    )
-  })
diff --git a/functions/src/on-create-group.ts b/functions/src/on-create-group.ts
deleted file mode 100644
index 5209788d..00000000
--- a/functions/src/on-create-group.ts
+++ /dev/null
@@ -1,28 +0,0 @@
-import * as functions from 'firebase-functions'
-import { getUser } from './utils'
-import { createNotification } from './create-notification'
-import { Group } from '../../common/group'
-
-export const onCreateGroup = functions.firestore
-  .document('groups/{groupId}')
-  .onCreate(async (change, context) => {
-    const group = change.data() as Group
-    const { eventId } = context
-
-    const groupCreator = await getUser(group.creatorId)
-    if (!groupCreator) throw new Error('Could not find group creator')
-    // create notifications for all members of the group
-    await createNotification(
-      group.id,
-      'group',
-      'created',
-      groupCreator,
-      eventId,
-      group.about,
-      {
-        recipients: group.memberIds,
-        slug: group.slug,
-        title: group.name,
-      }
-    )
-  })
diff --git a/functions/src/on-update-group.ts b/functions/src/on-update-group.ts
index 7e6a5697..93fb5550 100644
--- a/functions/src/on-update-group.ts
+++ b/functions/src/on-update-group.ts
@@ -15,21 +15,68 @@ export const onUpdateGroup = functions.firestore
     if (prevGroup.mostRecentActivityTime !== group.mostRecentActivityTime)
       return
 
-    if (prevGroup.contractIds.length < group.contractIds.length) {
-      await firestore
-        .collection('groups')
-        .doc(group.id)
-        .update({ mostRecentContractAddedTime: Date.now() })
-      //TODO: create notification with isSeeOnHref set to the group's /group/slug/questions url
-      // but first, let the new /group/slug/chat notification permeate so that we can differentiate between the two
-    }
-
     await firestore
       .collection('groups')
       .doc(group.id)
       .update({ mostRecentActivityTime: Date.now() })
   })
 
+export const onCreateGroupContract = functions.firestore
+  .document('groups/{groupId}/groupContracts/{contractId}')
+  .onCreate(async (change) => {
+    const groupId = change.ref.parent.parent?.id
+    if (groupId)
+      await firestore
+        .collection('groups')
+        .doc(groupId)
+        .update({
+          mostRecentContractAddedTime: Date.now(),
+          totalContracts: admin.firestore.FieldValue.increment(1),
+        })
+  })
+
+export const onDeleteGroupContract = functions.firestore
+  .document('groups/{groupId}/groupContracts/{contractId}')
+  .onDelete(async (change) => {
+    const groupId = change.ref.parent.parent?.id
+    if (groupId)
+      await firestore
+        .collection('groups')
+        .doc(groupId)
+        .update({
+          mostRecentContractAddedTime: Date.now(),
+          totalContracts: admin.firestore.FieldValue.increment(-1),
+        })
+  })
+
+export const onCreateGroupMember = functions.firestore
+  .document('groups/{groupId}/groupMembers/{memberId}')
+  .onCreate(async (change) => {
+    const groupId = change.ref.parent.parent?.id
+    if (groupId)
+      await firestore
+        .collection('groups')
+        .doc(groupId)
+        .update({
+          mostRecentActivityTime: Date.now(),
+          totalMembers: admin.firestore.FieldValue.increment(1),
+        })
+  })
+
+export const onDeleteGroupMember = functions.firestore
+  .document('groups/{groupId}/groupMembers/{memberId}')
+  .onDelete(async (change) => {
+    const groupId = change.ref.parent.parent?.id
+    if (groupId)
+      await firestore
+        .collection('groups')
+        .doc(groupId)
+        .update({
+          mostRecentActivityTime: Date.now(),
+          totalMembers: admin.firestore.FieldValue.increment(-1),
+        })
+  })
+
 export async function removeGroupLinks(group: Group, contractIds: string[]) {
   for (const contractId of contractIds) {
     const contract = await getContract(contractId)
diff --git a/functions/src/scripts/convert-categories.ts b/functions/src/scripts/convert-categories.ts
deleted file mode 100644
index 3436bcbc..00000000
--- a/functions/src/scripts/convert-categories.ts
+++ /dev/null
@@ -1,108 +0,0 @@
-import * as admin from 'firebase-admin'
-
-import { initAdmin } from './script-init'
-import { getValues, isProd } from '../utils'
-import { CATEGORIES_GROUP_SLUG_POSTFIX } from 'common/categories'
-import { Group, GroupLink } from 'common/group'
-import { uniq } from 'lodash'
-import { Contract } from 'common/contract'
-import { User } from 'common/user'
-import { filterDefined } from 'common/util/array'
-import {
-  DEV_HOUSE_LIQUIDITY_PROVIDER_ID,
-  HOUSE_LIQUIDITY_PROVIDER_ID,
-} from 'common/antes'
-
-initAdmin()
-
-const adminFirestore = admin.firestore()
-
-const convertCategoriesToGroupsInternal = async (categories: string[]) => {
-  for (const category of categories) {
-    const markets = await getValues<Contract>(
-      adminFirestore
-        .collection('contracts')
-        .where('lowercaseTags', 'array-contains', category.toLowerCase())
-    )
-    const slug = category.toLowerCase() + CATEGORIES_GROUP_SLUG_POSTFIX
-    const oldGroup = await getValues<Group>(
-      adminFirestore.collection('groups').where('slug', '==', slug)
-    )
-    if (oldGroup.length > 0) {
-      console.log(`Found old group for ${category}`)
-      await adminFirestore.collection('groups').doc(oldGroup[0].id).delete()
-    }
-
-    const allUsers = await getValues<User>(adminFirestore.collection('users'))
-    const groupUsers = filterDefined(
-      allUsers.map((user: User) => {
-        if (!user.followedCategories || user.followedCategories.length === 0)
-          return user.id
-        if (!user.followedCategories.includes(category.toLowerCase()))
-          return null
-        return user.id
-      })
-    )
-
-    const manifoldAccount = isProd()
-      ? HOUSE_LIQUIDITY_PROVIDER_ID
-      : DEV_HOUSE_LIQUIDITY_PROVIDER_ID
-    const newGroupRef = await adminFirestore.collection('groups').doc()
-    const newGroup: Group = {
-      id: newGroupRef.id,
-      name: category,
-      slug,
-      creatorId: manifoldAccount,
-      createdTime: Date.now(),
-      anyoneCanJoin: true,
-      memberIds: [manifoldAccount],
-      about: 'Default group for all things related to ' + category,
-      mostRecentActivityTime: Date.now(),
-      contractIds: markets.map((market) => market.id),
-      chatDisabled: true,
-    }
-
-    await adminFirestore.collection('groups').doc(newGroupRef.id).set(newGroup)
-    // Update group with new memberIds to avoid notifying everyone
-    await adminFirestore
-      .collection('groups')
-      .doc(newGroupRef.id)
-      .update({
-        memberIds: uniq(groupUsers),
-      })
-
-    for (const market of markets) {
-      if (market.groupLinks?.map((l) => l.groupId).includes(newGroup.id))
-        continue // already in that group
-
-      const newGroupLinks = [
-        ...(market.groupLinks ?? []),
-        {
-          groupId: newGroup.id,
-          createdTime: Date.now(),
-          slug: newGroup.slug,
-          name: newGroup.name,
-        } as GroupLink,
-      ]
-      await adminFirestore
-        .collection('contracts')
-        .doc(market.id)
-        .update({
-          groupSlugs: uniq([...(market.groupSlugs ?? []), newGroup.slug]),
-          groupLinks: newGroupLinks,
-        })
-    }
-  }
-}
-
-async function convertCategoriesToGroups() {
-  // const defaultCategories = Object.values(DEFAULT_CATEGORIES)
-  const moreCategories = ['world', 'culture']
-  await convertCategoriesToGroupsInternal(moreCategories)
-}
-
-if (require.main === module) {
-  convertCategoriesToGroups()
-    .then(() => process.exit())
-    .catch(console.log)
-}
diff --git a/functions/src/scripts/convert-tag-to-group.ts b/functions/src/scripts/convert-tag-to-group.ts
index 48f14e27..3240357e 100644
--- a/functions/src/scripts/convert-tag-to-group.ts
+++ b/functions/src/scripts/convert-tag-to-group.ts
@@ -4,21 +4,23 @@ import * as admin from 'firebase-admin'
 import { initAdmin } from './script-init'
 import { isProd, log } from '../utils'
 import { getSlug } from '../create-group'
-import { Group } from '../../../common/group'
+import { Group, GroupLink } from '../../../common/group'
+import { uniq } from 'lodash'
+import { Contract } from 'common/contract'
 
-const getTaggedContractIds = async (tag: string) => {
+const getTaggedContracts = async (tag: string) => {
   const firestore = admin.firestore()
   const results = await firestore
     .collection('contracts')
     .where('lowercaseTags', 'array-contains', tag.toLowerCase())
     .get()
-  return results.docs.map((d) => d.id)
+  return results.docs.map((d) => d.data() as Contract)
 }
 
 const createGroup = async (
   name: string,
   about: string,
-  contractIds: string[]
+  contracts: Contract[]
 ) => {
   const firestore = admin.firestore()
   const creatorId = isProd()
@@ -36,21 +38,60 @@ const createGroup = async (
     about,
     createdTime: now,
     mostRecentActivityTime: now,
-    contractIds: contractIds,
     anyoneCanJoin: true,
-    memberIds: [],
+    totalContracts: contracts.length,
+    totalMembers: 1,
   }
-  return await groupRef.create(group)
+  await groupRef.create(group)
+  // create a GroupMemberDoc for the creator
+  const memberDoc = groupRef.collection('groupMembers').doc(creatorId)
+  await memberDoc.create({
+    userId: creatorId,
+    createdTime: now,
+  })
+
+  // create GroupContractDocs for each contractId
+  await Promise.all(
+    contracts
+      .map((c) => c.id)
+      .map((contractId) =>
+        groupRef.collection('groupContracts').doc(contractId).create({
+          contractId,
+          createdTime: now,
+        })
+      )
+  )
+  for (const market of contracts) {
+    if (market.groupLinks?.map((l) => l.groupId).includes(group.id)) continue // already in that group
+
+    const newGroupLinks = [
+      ...(market.groupLinks ?? []),
+      {
+        groupId: group.id,
+        createdTime: Date.now(),
+        slug: group.slug,
+        name: group.name,
+      } as GroupLink,
+    ]
+    await firestore
+      .collection('contracts')
+      .doc(market.id)
+      .update({
+        groupSlugs: uniq([...(market.groupSlugs ?? []), group.slug]),
+        groupLinks: newGroupLinks,
+      })
+  }
+  return { status: 'success', group: group }
 }
 
 const convertTagToGroup = async (tag: string, groupName: string) => {
   log(`Looking up contract IDs with tag ${tag}...`)
-  const contractIds = await getTaggedContractIds(tag)
-  log(`${contractIds.length} contracts found.`)
-  if (contractIds.length > 0) {
+  const contracts = await getTaggedContracts(tag)
+  log(`${contracts.length} contracts found.`)
+  if (contracts.length > 0) {
     log(`Creating group ${groupName}...`)
     const about = `Contracts that used to be tagged ${tag}.`
-    const result = await createGroup(groupName, about, contractIds)
+    const result = await createGroup(groupName, about, contracts)
     log(`Done. Group: `, result)
   }
 }
diff --git a/functions/src/scripts/update-groups.ts b/functions/src/scripts/update-groups.ts
new file mode 100644
index 00000000..952a0d55
--- /dev/null
+++ b/functions/src/scripts/update-groups.ts
@@ -0,0 +1,109 @@
+import * as admin from 'firebase-admin'
+import { Group } from 'common/group'
+import { initAdmin } from 'functions/src/scripts/script-init'
+import { log } from '../utils'
+
+const getGroups = async () => {
+  const firestore = admin.firestore()
+  const groups = await firestore.collection('groups').get()
+  return groups.docs.map((doc) => doc.data() as Group)
+}
+
+const createContractIdForGroup = async (
+  groupId: string,
+  contractId: string
+) => {
+  const firestore = admin.firestore()
+  const now = Date.now()
+  const contractDoc = await firestore
+    .collection('groups')
+    .doc(groupId)
+    .collection('groupContracts')
+    .doc(contractId)
+    .get()
+  if (!contractDoc.exists)
+    await firestore
+      .collection('groups')
+      .doc(groupId)
+      .collection('groupContracts')
+      .doc(contractId)
+      .create({
+        contractId,
+        createdTime: now,
+      })
+}
+
+const createMemberForGroup = async (groupId: string, userId: string) => {
+  const firestore = admin.firestore()
+  const now = Date.now()
+  const memberDoc = await firestore
+    .collection('groups')
+    .doc(groupId)
+    .collection('groupMembers')
+    .doc(userId)
+    .get()
+  if (!memberDoc.exists)
+    await firestore
+      .collection('groups')
+      .doc(groupId)
+      .collection('groupMembers')
+      .doc(userId)
+      .create({
+        userId,
+        createdTime: now,
+      })
+}
+
+// eslint-disable-next-line @typescript-eslint/no-unused-vars
+async function convertGroupFieldsToGroupDocuments() {
+  const groups = await getGroups()
+  for (const group of groups) {
+    log('updating group', group.slug)
+    const groupRef = admin.firestore().collection('groups').doc(group.id)
+    const totalMembers = (await groupRef.collection('groupMembers').get()).size
+    const totalContracts = (await groupRef.collection('groupContracts').get())
+      .size
+    if (
+      totalMembers === group.memberIds?.length &&
+      totalContracts === group.contractIds?.length
+    ) {
+      log('group already converted', group.slug)
+      continue
+    }
+    const contractStart = totalContracts - 1 < 0 ? 0 : totalContracts - 1
+    const membersStart = totalMembers - 1 < 0 ? 0 : totalMembers - 1
+    for (const contractId of group.contractIds?.slice(
+      contractStart,
+      group.contractIds?.length
+    ) ?? []) {
+      await createContractIdForGroup(group.id, contractId)
+    }
+    for (const userId of group.memberIds?.slice(
+      membersStart,
+      group.memberIds?.length
+    ) ?? []) {
+      await createMemberForGroup(group.id, userId)
+    }
+  }
+}
+
+async function updateTotalContractsAndMembers() {
+  const groups = await getGroups()
+  for (const group of groups) {
+    log('updating group total contracts and members', group.slug)
+    const groupRef = admin.firestore().collection('groups').doc(group.id)
+    const totalMembers = (await groupRef.collection('groupMembers').get()).size
+    const totalContracts = (await groupRef.collection('groupContracts').get())
+      .size
+    await groupRef.update({
+      totalMembers,
+      totalContracts,
+    })
+  }
+}
+
+if (require.main === module) {
+  initAdmin()
+  // convertGroupFieldsToGroupDocuments()
+  updateTotalContractsAndMembers()
+}
diff --git a/web/components/contract-search.tsx b/web/components/contract-search.tsx
index f8b7622e..a0396d2e 100644
--- a/web/components/contract-search.tsx
+++ b/web/components/contract-search.tsx
@@ -282,8 +282,8 @@ function ContractSearchControls(props: {
       : DEFAULT_CATEGORY_GROUPS.map((g) => g.slug)
 
   const memberPillGroups = sortBy(
-    memberGroups.filter((group) => group.contractIds.length > 0),
-    (group) => group.contractIds.length
+    memberGroups.filter((group) => group.totalContracts > 0),
+    (group) => group.totalContracts
   ).reverse()
 
   const pillGroups: { name: string; slug: string }[] =
diff --git a/web/components/groups/contract-groups-list.tsx b/web/components/groups/contract-groups-list.tsx
index 7bbcfa7c..d39a35d3 100644
--- a/web/components/groups/contract-groups-list.tsx
+++ b/web/components/groups/contract-groups-list.tsx
@@ -7,13 +7,13 @@ import { Button } from 'web/components/button'
 import { GroupSelector } from 'web/components/groups/group-selector'
 import {
   addContractToGroup,
-  canModifyGroupContracts,
   removeContractFromGroup,
 } from 'web/lib/firebase/groups'
 import { User } from 'common/user'
 import { Contract } from 'common/contract'
 import { SiteLink } from 'web/components/site-link'
-import { useGroupsWithContract } from 'web/hooks/use-group'
+import { useGroupsWithContract, useMemberGroupIds } from 'web/hooks/use-group'
+import { Group } from 'common/group'
 
 export function ContractGroupsList(props: {
   contract: Contract
@@ -22,6 +22,15 @@ export function ContractGroupsList(props: {
   const { user, contract } = props
   const { groupLinks } = contract
   const groups = useGroupsWithContract(contract)
+  const memberGroupIds = useMemberGroupIds(user)
+
+  const canModifyGroupContracts = (group: Group, userId: string) => {
+    return (
+      group.creatorId === userId ||
+      group.anyoneCanJoin ||
+      memberGroupIds?.includes(group.id)
+    )
+  }
   return (
     <Col className={'gap-2'}>
       <span className={'text-xl text-indigo-700'}>
@@ -61,7 +70,7 @@ export function ContractGroupsList(props: {
             <Button
               color={'gray-white'}
               size={'xs'}
-              onClick={() => removeContractFromGroup(group, contract, user.id)}
+              onClick={() => removeContractFromGroup(group, contract)}
             >
               <XIcon className="h-4 w-4 text-gray-500" />
             </Button>
diff --git a/web/components/groups/edit-group-button.tsx b/web/components/groups/edit-group-button.tsx
index 834af5ec..6349ad3f 100644
--- a/web/components/groups/edit-group-button.tsx
+++ b/web/components/groups/edit-group-button.tsx
@@ -3,17 +3,16 @@ import clsx from 'clsx'
 import { PencilIcon } from '@heroicons/react/outline'
 
 import { Group } from 'common/group'
-import { deleteGroup, updateGroup } from 'web/lib/firebase/groups'
+import { deleteGroup, joinGroup } from 'web/lib/firebase/groups'
 import { Spacer } from '../layout/spacer'
 import { useRouter } from 'next/router'
 import { Modal } from 'web/components/layout/modal'
 import { FilterSelectUsers } from 'web/components/filter-select-users'
 import { User } from 'common/user'
-import { uniq } from 'lodash'
+import { useMemberIds } from 'web/hooks/use-group'
 
 export function EditGroupButton(props: { group: Group; className?: string }) {
   const { group, className } = props
-  const { memberIds } = group
   const router = useRouter()
 
   const [name, setName] = useState(group.name)
@@ -21,7 +20,7 @@ export function EditGroupButton(props: { group: Group; className?: string }) {
   const [open, setOpen] = useState(false)
   const [isSubmitting, setIsSubmitting] = useState(false)
   const [addMemberUsers, setAddMemberUsers] = useState<User[]>([])
-
+  const memberIds = useMemberIds(group.id)
   function updateOpen(newOpen: boolean) {
     setAddMemberUsers([])
     setOpen(newOpen)
@@ -33,11 +32,7 @@ export function EditGroupButton(props: { group: Group; className?: string }) {
   const onSubmit = async () => {
     setIsSubmitting(true)
 
-    await updateGroup(group, {
-      name,
-      about,
-      memberIds: uniq([...memberIds, ...addMemberUsers.map((user) => user.id)]),
-    })
+    await Promise.all(addMemberUsers.map((user) => joinGroup(group, user.id)))
 
     setIsSubmitting(false)
     updateOpen(false)
diff --git a/web/components/groups/group-chat.tsx b/web/components/groups/group-chat.tsx
deleted file mode 100644
index 9a60c9c7..00000000
--- a/web/components/groups/group-chat.tsx
+++ /dev/null
@@ -1,391 +0,0 @@
-import { Row } from 'web/components/layout/row'
-import { Col } from 'web/components/layout/col'
-import { PrivateUser, User } from 'common/user'
-import React, { useEffect, memo, useState, useMemo } from 'react'
-import { Avatar } from 'web/components/avatar'
-import { Group } from 'common/group'
-import { Comment, GroupComment } from 'common/comment'
-import { createCommentOnGroup } from 'web/lib/firebase/comments'
-import { CommentInputTextArea } from 'web/components/feed/feed-comments'
-import { track } from 'web/lib/service/analytics'
-import { firebaseLogin } from 'web/lib/firebase/users'
-import { useRouter } from 'next/router'
-import clsx from 'clsx'
-import { CopyLinkDateTimeComponent } from 'web/components/feed/copy-link-date-time'
-import { CommentTipMap, CommentTips } from 'web/hooks/use-tip-txns'
-import { Tipper } from 'web/components/tipper'
-import { sum } from 'lodash'
-import { formatMoney } from 'common/util/format'
-import { useWindowSize } from 'web/hooks/use-window-size'
-import { Content, useTextEditor } from 'web/components/editor'
-import { useUnseenNotifications } from 'web/hooks/use-notifications'
-import { ChevronDownIcon, UsersIcon } from '@heroicons/react/outline'
-import { setNotificationsAsSeen } from 'web/pages/notifications'
-import { usePrivateUser } from 'web/hooks/use-user'
-import { UserLink } from 'web/components/user-link'
-
-export function GroupChat(props: {
-  messages: GroupComment[]
-  user: User | null | undefined
-  group: Group
-  tips: CommentTipMap
-}) {
-  const { messages, user, group, tips } = props
-
-  const privateUser = usePrivateUser()
-
-  const { editor, upload } = useTextEditor({
-    simple: true,
-    placeholder: 'Send a message',
-  })
-  const [isSubmitting, setIsSubmitting] = useState(false)
-  const [scrollToBottomRef, setScrollToBottomRef] =
-    useState<HTMLDivElement | null>(null)
-  const [scrollToMessageId, setScrollToMessageId] = useState('')
-  const [scrollToMessageRef, setScrollToMessageRef] =
-    useState<HTMLDivElement | null>(null)
-  const [replyToUser, setReplyToUser] = useState<any>()
-
-  const router = useRouter()
-  const isMember = user && group.memberIds.includes(user?.id)
-
-  const { width, height } = useWindowSize()
-  const [containerRef, setContainerRef] = useState<HTMLDivElement | null>(null)
-  // Subtract bottom bar when it's showing (less than lg screen)
-  const bottomBarHeight = (width ?? 0) < 1024 ? 58 : 0
-  const remainingHeight =
-    (height ?? 0) - (containerRef?.offsetTop ?? 0) - bottomBarHeight
-
-  // array of groups, where each group is an array of messages that are displayed as one
-  const groupedMessages = useMemo(() => {
-    // Group messages with createdTime within 2 minutes of each other.
-    const tempGrouped: GroupComment[][] = []
-    for (let i = 0; i < messages.length; i++) {
-      const message = messages[i]
-      if (i === 0) tempGrouped.push([message])
-      else {
-        const prevMessage = messages[i - 1]
-        const diff = message.createdTime - prevMessage.createdTime
-        const creatorsMatch = message.userId === prevMessage.userId
-        if (diff < 2 * 60 * 1000 && creatorsMatch) {
-          tempGrouped.at(-1)?.push(message)
-        } else {
-          tempGrouped.push([message])
-        }
-      }
-    }
-
-    return tempGrouped
-  }, [messages])
-
-  useEffect(() => {
-    scrollToMessageRef?.scrollIntoView()
-  }, [scrollToMessageRef])
-
-  useEffect(() => {
-    if (scrollToBottomRef)
-      scrollToBottomRef.scrollTo({ top: scrollToBottomRef.scrollHeight || 0 })
-    // Must also listen to groupedMessages as they update the height of the messaging window
-  }, [scrollToBottomRef, groupedMessages])
-
-  useEffect(() => {
-    const elementInUrl = router.asPath.split('#')[1]
-    if (messages.map((m) => m.id).includes(elementInUrl)) {
-      setScrollToMessageId(elementInUrl)
-    }
-  }, [messages, router.asPath])
-
-  useEffect(() => {
-    // is mobile?
-    if (width && width > 720) focusInput()
-    // eslint-disable-next-line react-hooks/exhaustive-deps
-  }, [width])
-
-  function onReplyClick(comment: Comment) {
-    setReplyToUser({ id: comment.userId, username: comment.userUsername })
-  }
-
-  async function submitMessage() {
-    if (!user) {
-      track('sign in to comment')
-      return await firebaseLogin()
-    }
-    if (!editor || editor.isEmpty || isSubmitting) return
-    setIsSubmitting(true)
-    await createCommentOnGroup(group.id, editor.getJSON(), user)
-    editor.commands.clearContent()
-    setIsSubmitting(false)
-    setReplyToUser(undefined)
-    focusInput()
-  }
-  function focusInput() {
-    editor?.commands.focus()
-  }
-
-  return (
-    <Col ref={setContainerRef} style={{ height: remainingHeight }}>
-      <Col
-        className={
-          'w-full flex-1 space-y-2 overflow-x-hidden overflow-y-scroll pt-2'
-        }
-        ref={setScrollToBottomRef}
-      >
-        {groupedMessages.map((messages) => (
-          <GroupMessage
-            user={user}
-            key={`group ${messages[0].id}`}
-            comments={messages}
-            group={group}
-            onReplyClick={onReplyClick}
-            highlight={messages[0].id === scrollToMessageId}
-            setRef={
-              scrollToMessageId === messages[0].id
-                ? setScrollToMessageRef
-                : undefined
-            }
-            tips={tips[messages[0].id] ?? {}}
-          />
-        ))}
-        {messages.length === 0 && (
-          <div className="p-2 text-gray-500">
-            No messages yet. Why not{isMember ? ` ` : ' join and '}
-            <button
-              className={'cursor-pointer font-bold text-gray-700'}
-              onClick={focusInput}
-            >
-              add one?
-            </button>
-          </div>
-        )}
-      </Col>
-      {user && group.memberIds.includes(user.id) && (
-        <div className="flex w-full justify-start gap-2 p-2">
-          <div className="mt-1">
-            <Avatar
-              username={user?.username}
-              avatarUrl={user?.avatarUrl}
-              size={'sm'}
-            />
-          </div>
-          <div className={'flex-1'}>
-            <CommentInputTextArea
-              editor={editor}
-              upload={upload}
-              user={user}
-              replyToUser={replyToUser}
-              submitComment={submitMessage}
-              isSubmitting={isSubmitting}
-              submitOnEnter
-            />
-          </div>
-        </div>
-      )}
-
-      {privateUser && (
-        <GroupChatNotificationsIcon
-          group={group}
-          privateUser={privateUser}
-          shouldSetAsSeen={true}
-          hidden={true}
-        />
-      )}
-    </Col>
-  )
-}
-
-export function GroupChatInBubble(props: {
-  messages: GroupComment[]
-  user: User | null | undefined
-  privateUser: PrivateUser | null | undefined
-  group: Group
-  tips: CommentTipMap
-}) {
-  const { messages, user, group, tips, privateUser } = props
-  const [shouldShowChat, setShouldShowChat] = useState(false)
-  const router = useRouter()
-
-  useEffect(() => {
-    const groupsWithChatEmphasis = [
-      'welcome',
-      'bugs',
-      'manifold-features-25bad7c7792e',
-      'updates',
-    ]
-    if (
-      router.asPath.includes('/chat') ||
-      groupsWithChatEmphasis.includes(
-        router.asPath.split('/group/')[1].split('/')[0]
-      )
-    ) {
-      setShouldShowChat(true)
-    }
-    // Leave chat open between groups if user is using chat?
-    else {
-      setShouldShowChat(false)
-    }
-  }, [router.asPath])
-
-  return (
-    <Col
-      className={clsx(
-        'fixed right-0 bottom-[0px] h-1 w-full sm:bottom-[20px] sm:right-20 sm:w-2/3 md:w-1/2 lg:right-24 lg:w-1/3 xl:right-32 xl:w-1/4',
-        shouldShowChat ? 'p-2m z-10 h-screen bg-white' : ''
-      )}
-    >
-      {shouldShowChat && (
-        <GroupChat messages={messages} user={user} group={group} tips={tips} />
-      )}
-      <button
-        type="button"
-        className={clsx(
-          'fixed right-1 inline-flex items-center rounded-full border md:right-2 lg:right-5 xl:right-10' +
-            ' border-transparent p-3 text-white shadow-sm lg:p-4' +
-            ' focus:outline-none focus:ring-2  focus:ring-offset-2 ' +
-            ' bottom-[70px] ',
-          shouldShowChat
-            ? 'bottom-auto top-2 bg-gray-600 hover:bg-gray-400 focus:ring-gray-500 sm:bottom-[70px] sm:top-auto '
-            : ' bg-indigo-600  hover:bg-indigo-700 focus:ring-indigo-500'
-        )}
-        onClick={() => {
-          // router.push('/chat')
-          setShouldShowChat(!shouldShowChat)
-          track('mobile group chat button')
-        }}
-      >
-        {!shouldShowChat ? (
-          <UsersIcon className="h-10 w-10" aria-hidden="true" />
-        ) : (
-          <ChevronDownIcon className={'h-10 w-10'} aria-hidden={'true'} />
-        )}
-        {privateUser && (
-          <GroupChatNotificationsIcon
-            group={group}
-            privateUser={privateUser}
-            shouldSetAsSeen={shouldShowChat}
-            hidden={false}
-          />
-        )}
-      </button>
-    </Col>
-  )
-}
-
-function GroupChatNotificationsIcon(props: {
-  group: Group
-  privateUser: PrivateUser
-  shouldSetAsSeen: boolean
-  hidden: boolean
-}) {
-  const { privateUser, group, shouldSetAsSeen, hidden } = props
-  const notificationsForThisGroup = useUnseenNotifications(
-    privateUser
-    // Disabled tracking by customHref for now.
-    // {
-    //   customHref: `/group/${group.slug}`,
-    // }
-  )
-
-  useEffect(() => {
-    if (!notificationsForThisGroup) return
-
-    notificationsForThisGroup.forEach((notification) => {
-      if (
-        (shouldSetAsSeen && notification.isSeenOnHref?.includes('chat')) ||
-        // old style chat notif that simply ended with the group slug
-        notification.isSeenOnHref?.endsWith(group.slug)
-      ) {
-        setNotificationsAsSeen([notification])
-      }
-    })
-  }, [group.slug, notificationsForThisGroup, shouldSetAsSeen])
-
-  return (
-    <div
-      className={
-        !hidden &&
-        notificationsForThisGroup &&
-        notificationsForThisGroup.length > 0 &&
-        !shouldSetAsSeen
-          ? 'absolute right-4 top-4 h-3 w-3 rounded-full border-2 border-white bg-red-500'
-          : 'hidden'
-      }
-    ></div>
-  )
-}
-
-const GroupMessage = memo(function GroupMessage_(props: {
-  user: User | null | undefined
-  comments: GroupComment[]
-  group: Group
-  onReplyClick?: (comment: Comment) => void
-  setRef?: (ref: HTMLDivElement) => void
-  highlight?: boolean
-  tips: CommentTips
-}) {
-  const { comments, onReplyClick, group, setRef, highlight, user, tips } = props
-  const first = comments[0]
-  const { id, userUsername, userName, userAvatarUrl, createdTime } = first
-
-  const isCreatorsComment = user && first.userId === user.id
-  return (
-    <Col
-      ref={setRef}
-      className={clsx(
-        isCreatorsComment ? 'mr-2 self-end' : '',
-        'w-fit max-w-sm gap-1 space-x-3 rounded-md bg-white p-1 text-sm text-gray-500 transition-colors duration-1000  sm:max-w-md sm:p-3 sm:leading-[1.3rem]',
-        highlight ? `-m-1 bg-indigo-500/[0.2] p-2` : ''
-      )}
-    >
-      <Row className={'items-center'}>
-        {!isCreatorsComment && (
-          <Col>
-            <Avatar
-              className={'mx-2 ml-2.5'}
-              size={'xs'}
-              username={userUsername}
-              avatarUrl={userAvatarUrl}
-            />
-          </Col>
-        )}
-        {!isCreatorsComment ? (
-          <UserLink username={userUsername} name={userName} />
-        ) : (
-          <span className={'ml-2.5'}>{'You'}</span>
-        )}
-        <CopyLinkDateTimeComponent
-          prefix={'group'}
-          slug={group.slug}
-          createdTime={createdTime}
-          elementId={id}
-        />
-      </Row>
-      <div className="mt-2 text-base text-black">
-        {comments.map((comment) => (
-          <Content
-            key={comment.id}
-            content={comment.content || comment.text}
-            smallImage
-          />
-        ))}
-      </div>
-      <Row>
-        {!isCreatorsComment && onReplyClick && (
-          <button
-            className={
-              'self-start py-1 text-xs font-bold text-gray-500 hover:underline'
-            }
-            onClick={() => onReplyClick(first)}
-          >
-            Reply
-          </button>
-        )}
-        {isCreatorsComment && sum(Object.values(tips)) > 0 && (
-          <span className={'text-primary'}>
-            {formatMoney(sum(Object.values(tips)))}
-          </span>
-        )}
-        {!isCreatorsComment && <Tipper comment={first} tips={tips} />}
-      </Row>
-    </Col>
-  )
-})
diff --git a/web/components/groups/groups-button.tsx b/web/components/groups/groups-button.tsx
index bb94c9ed..810a70bc 100644
--- a/web/components/groups/groups-button.tsx
+++ b/web/components/groups/groups-button.tsx
@@ -1,10 +1,10 @@
 import clsx from 'clsx'
 import { User } from 'common/user'
-import { useEffect, useState } from 'react'
+import { useState } from 'react'
 import { useUser } from 'web/hooks/use-user'
 import { withTracking } from 'web/lib/service/analytics'
 import { Row } from 'web/components/layout/row'
-import { useMemberGroups } from 'web/hooks/use-group'
+import { useMemberGroups, useMemberIds } from 'web/hooks/use-group'
 import { TextButton } from 'web/components/text-button'
 import { Group } from 'common/group'
 import { Modal } from 'web/components/layout/modal'
@@ -17,9 +17,7 @@ import toast from 'react-hot-toast'
 export function GroupsButton(props: { user: User }) {
   const { user } = props
   const [isOpen, setIsOpen] = useState(false)
-  const groups = useMemberGroups(user.id, undefined, {
-    by: 'mostRecentChatActivityTime',
-  })
+  const groups = useMemberGroups(user.id)
 
   return (
     <>
@@ -91,34 +89,12 @@ export function JoinOrLeaveGroupButton(props: {
 }) {
   const { group, small, className } = props
   const currentUser = useUser()
-  const [isMember, setIsMember] = useState<boolean>(false)
-  useEffect(() => {
-    if (currentUser && group.memberIds.includes(currentUser.id)) {
-      setIsMember(group.memberIds.includes(currentUser.id))
-    }
-  }, [currentUser, group])
-
-  const onJoinGroup = () => {
-    if (!currentUser) return
-    setIsMember(true)
-    joinGroup(group, currentUser.id).catch(() => {
-      setIsMember(false)
-      toast.error('Failed to join group')
-    })
-  }
-  const onLeaveGroup = () => {
-    if (!currentUser) return
-    setIsMember(false)
-    leaveGroup(group, currentUser.id).catch(() => {
-      setIsMember(true)
-      toast.error('Failed to leave group')
-    })
-  }
-
+  const memberIds = useMemberIds(group.id)
+  const isMember = memberIds?.includes(currentUser?.id ?? '') ?? false
   const smallStyle =
     'btn !btn-xs border-2 border-gray-500 bg-white normal-case text-gray-500 hover:border-gray-500 hover:bg-white hover:text-gray-500'
 
-  if (!currentUser || isMember === undefined) {
+  if (!currentUser) {
     if (!group.anyoneCanJoin)
       return <div className={clsx(className, 'text-gray-500')}>Closed</div>
     return (
@@ -130,6 +106,16 @@ export function JoinOrLeaveGroupButton(props: {
       </button>
     )
   }
+  const onJoinGroup = () => {
+    joinGroup(group, currentUser.id).catch(() => {
+      toast.error('Failed to join group')
+    })
+  }
+  const onLeaveGroup = () => {
+    leaveGroup(group, currentUser.id).catch(() => {
+      toast.error('Failed to leave group')
+    })
+  }
 
   if (isMember) {
     return (
diff --git a/web/hooks/use-group.ts b/web/hooks/use-group.ts
index aeeaf2ab..001c29c3 100644
--- a/web/hooks/use-group.ts
+++ b/web/hooks/use-group.ts
@@ -2,16 +2,21 @@ import { useEffect, useState } from 'react'
 import { Group } from 'common/group'
 import { User } from 'common/user'
 import {
+  GroupMemberDoc,
+  groupMembers,
   listenForGroup,
+  listenForGroupContractDocs,
   listenForGroups,
+  listenForMemberGroupIds,
   listenForMemberGroups,
   listenForOpenGroups,
   listGroups,
 } from 'web/lib/firebase/groups'
-import { getUser, getUsers } from 'web/lib/firebase/users'
+import { getUser } from 'web/lib/firebase/users'
 import { filterDefined } from 'common/util/array'
 import { Contract } from 'common/contract'
 import { uniq } from 'lodash'
+import { listenForValues } from 'web/lib/firebase/utils'
 
 export const useGroup = (groupId: string | undefined) => {
   const [group, setGroup] = useState<Group | null | undefined>()
@@ -43,29 +48,12 @@ export const useOpenGroups = () => {
   return groups
 }
 
-export const useMemberGroups = (
-  userId: string | null | undefined,
-  options?: { withChatEnabled: boolean },
-  sort?: { by: 'mostRecentChatActivityTime' | 'mostRecentContractAddedTime' }
-) => {
+export const useMemberGroups = (userId: string | null | undefined) => {
   const [memberGroups, setMemberGroups] = useState<Group[] | undefined>()
   useEffect(() => {
     if (userId)
-      return listenForMemberGroups(
-        userId,
-        (groups) => {
-          if (options?.withChatEnabled)
-            return setMemberGroups(
-              filterDefined(
-                groups.filter((group) => group.chatDisabled !== true)
-              )
-            )
-          return setMemberGroups(groups)
-        },
-        sort
-      )
-    // eslint-disable-next-line react-hooks/exhaustive-deps
-  }, [options?.withChatEnabled, sort?.by, userId])
+      return listenForMemberGroups(userId, (groups) => setMemberGroups(groups))
+  }, [userId])
   return memberGroups
 }
 
@@ -77,16 +65,8 @@ export const useMemberGroupIds = (user: User | null | undefined) => {
 
   useEffect(() => {
     if (user) {
-      const key = `member-groups-${user.id}`
-      const memberGroupJson = localStorage.getItem(key)
-      if (memberGroupJson) {
-        setMemberGroupIds(JSON.parse(memberGroupJson))
-      }
-
-      return listenForMemberGroups(user.id, (Groups) => {
-        const groupIds = Groups.map((group) => group.id)
+      return listenForMemberGroupIds(user.id, (groupIds) => {
         setMemberGroupIds(groupIds)
-        localStorage.setItem(key, JSON.stringify(groupIds))
       })
     }
   }, [user])
@@ -94,26 +74,29 @@ export const useMemberGroupIds = (user: User | null | undefined) => {
   return memberGroupIds
 }
 
-export function useMembers(group: Group, max?: number) {
+export function useMembers(groupId: string | undefined) {
   const [members, setMembers] = useState<User[]>([])
   useEffect(() => {
-    const { memberIds } = group
-    if (memberIds.length > 0) {
-      listMembers(group, max).then((members) => setMembers(members))
-    }
-  }, [group, max])
+    if (groupId)
+      listenForValues<GroupMemberDoc>(groupMembers(groupId), (memDocs) => {
+        const memberIds = memDocs.map((memDoc) => memDoc.userId)
+        Promise.all(memberIds.map((id) => getUser(id))).then((users) => {
+          setMembers(users)
+        })
+      })
+  }, [groupId])
   return members
 }
 
-export async function listMembers(group: Group, max?: number) {
-  const { memberIds } = group
-  const numToRetrieve = max ?? memberIds.length
-  if (memberIds.length === 0) return []
-  if (numToRetrieve > 100)
-    return (await getUsers()).filter((user) =>
-      group.memberIds.includes(user.id)
-    )
-  return await Promise.all(group.memberIds.slice(0, numToRetrieve).map(getUser))
+export function useMemberIds(groupId: string | null) {
+  const [memberIds, setMemberIds] = useState<string[]>([])
+  useEffect(() => {
+    if (groupId)
+      return listenForValues<GroupMemberDoc>(groupMembers(groupId), (docs) => {
+        setMemberIds(docs.map((doc) => doc.userId))
+      })
+  }, [groupId])
+  return memberIds
 }
 
 export const useGroupsWithContract = (contract: Contract) => {
@@ -128,3 +111,16 @@ export const useGroupsWithContract = (contract: Contract) => {
 
   return groups
 }
+
+export function useGroupContractIds(groupId: string) {
+  const [contractIds, setContractIds] = useState<string[]>([])
+
+  useEffect(() => {
+    if (groupId)
+      return listenForGroupContractDocs(groupId, (docs) =>
+        setContractIds(docs.map((doc) => doc.contractId))
+      )
+  }, [groupId])
+
+  return contractIds
+}
diff --git a/web/lib/firebase/groups.ts b/web/lib/firebase/groups.ts
index 4d22e0ee..ef67ff14 100644
--- a/web/lib/firebase/groups.ts
+++ b/web/lib/firebase/groups.ts
@@ -1,13 +1,17 @@
 import {
+  collection,
+  collectionGroup,
   deleteDoc,
   deleteField,
   doc,
   getDocs,
+  onSnapshot,
   query,
+  setDoc,
   updateDoc,
   where,
 } from 'firebase/firestore'
-import { sortBy, uniq } from 'lodash'
+import { uniq } from 'lodash'
 import { Group, GROUP_CHAT_SLUG, GroupLink } from 'common/group'
 import {
   coll,
@@ -18,8 +22,15 @@ import {
 } from './utils'
 import { Contract } from 'common/contract'
 import { updateContract } from 'web/lib/firebase/contracts'
+import { db } from 'web/lib/firebase/init'
+import { filterDefined } from 'common/util/array'
+import { getUser } from 'web/lib/firebase/users'
 
 export const groups = coll<Group>('groups')
+export const groupMembers = (groupId: string) =>
+  collection(groups, groupId, 'groupMembers')
+export const groupContracts = (groupId: string) =>
+  collection(groups, groupId, 'groupContracts')
 
 export function groupPath(
   groupSlug: string,
@@ -33,6 +44,9 @@ export function groupPath(
   return `/group/${groupSlug}${subpath ? `/${subpath}` : ''}`
 }
 
+export type GroupContractDoc = { contractId: string; createdTime: number }
+export type GroupMemberDoc = { userId: string; createdTime: number }
+
 export function updateGroup(group: Group, updates: Partial<Group>) {
   return updateDoc(doc(groups, group.id), updates)
 }
@@ -57,6 +71,13 @@ export function listenForGroups(setGroups: (groups: Group[]) => void) {
   return listenForValues(groups, setGroups)
 }
 
+export function listenForGroupContractDocs(
+  groupId: string,
+  setContractDocs: (docs: GroupContractDoc[]) => void
+) {
+  return listenForValues(groupContracts(groupId), setContractDocs)
+}
+
 export function listenForOpenGroups(setGroups: (groups: Group[]) => void) {
   return listenForValues(
     query(groups, where('anyoneCanJoin', '==', true)),
@@ -68,6 +89,12 @@ export function getGroup(groupId: string) {
   return getValue<Group>(doc(groups, groupId))
 }
 
+export function getGroupContracts(groupId: string) {
+  return getValues<{ contractId: string; createdTime: number }>(
+    groupContracts(groupId)
+  )
+}
+
 export async function getGroupBySlug(slug: string) {
   const q = query(groups, where('slug', '==', slug))
   const docs = (await getDocs(q)).docs
@@ -81,33 +108,32 @@ export function listenForGroup(
   return listenForValue(doc(groups, groupId), setGroup)
 }
 
-export function listenForMemberGroups(
+export function listenForMemberGroupIds(
   userId: string,
-  setGroups: (groups: Group[]) => void,
-  sort?: { by: 'mostRecentChatActivityTime' | 'mostRecentContractAddedTime' }
+  setGroupIds: (groupIds: string[]) => void
 ) {
-  const q = query(groups, where('memberIds', 'array-contains', userId))
-  const sorter = (group: Group) => {
-    if (sort?.by === 'mostRecentChatActivityTime') {
-      return group.mostRecentChatActivityTime ?? group.createdTime
-    }
-    if (sort?.by === 'mostRecentContractAddedTime') {
-      return group.mostRecentContractAddedTime ?? group.createdTime
-    }
-    return group.mostRecentActivityTime
-  }
-  return listenForValues<Group>(q, (groups) => {
-    const sorted = sortBy(groups, [(group) => -sorter(group)])
-    setGroups(sorted)
+  const q = query(
+    collectionGroup(db, 'groupMembers'),
+    where('userId', '==', userId)
+  )
+  return onSnapshot(q, { includeMetadataChanges: true }, (snapshot) => {
+    if (snapshot.metadata.fromCache) return
+
+    const values = snapshot.docs.map((doc) => doc.ref.parent.parent?.id)
+
+    setGroupIds(filterDefined(values))
   })
 }
 
-export async function listenForGroupsWithContractId(
-  contractId: string,
+export function listenForMemberGroups(
+  userId: string,
   setGroups: (groups: Group[]) => void
 ) {
-  const q = query(groups, where('contractIds', 'array-contains', contractId))
-  return listenForValues<Group>(q, setGroups)
+  return listenForMemberGroupIds(userId, (groupIds) => {
+    return Promise.all(groupIds.map(getGroup)).then((groups) => {
+      setGroups(filterDefined(groups))
+    })
+  })
 }
 
 export async function addUserToGroupViaId(groupId: string, userId: string) {
@@ -121,19 +147,18 @@ export async function addUserToGroupViaId(groupId: string, userId: string) {
 }
 
 export async function joinGroup(group: Group, userId: string): Promise<void> {
-  const { memberIds } = group
-  if (memberIds.includes(userId)) return // already a member
-
-  const newMemberIds = [...memberIds, userId]
-  return await updateGroup(group, { memberIds: uniq(newMemberIds) })
+  // create a new member document in grouoMembers collection
+  const memberDoc = doc(groupMembers(group.id), userId)
+  return await setDoc(memberDoc, {
+    userId,
+    createdTime: Date.now(),
+  })
 }
 
 export async function leaveGroup(group: Group, userId: string): Promise<void> {
-  const { memberIds } = group
-  if (!memberIds.includes(userId)) return // not a member
-
-  const newMemberIds = memberIds.filter((id) => id !== userId)
-  return await updateGroup(group, { memberIds: uniq(newMemberIds) })
+  // delete the member document in groupMembers collection
+  const memberDoc = doc(groupMembers(group.id), userId)
+  return await deleteDoc(memberDoc)
 }
 
 export async function addContractToGroup(
@@ -141,7 +166,6 @@ export async function addContractToGroup(
   contract: Contract,
   userId: string
 ) {
-  if (!canModifyGroupContracts(group, userId)) return
   const newGroupLinks = [
     ...(contract.groupLinks ?? []),
     {
@@ -158,25 +182,18 @@ export async function addContractToGroup(
     groupLinks: newGroupLinks,
   })
 
-  if (!group.contractIds.includes(contract.id)) {
-    return await updateGroup(group, {
-      contractIds: uniq([...group.contractIds, contract.id]),
-    })
-      .then(() => group)
-      .catch((err) => {
-        console.error('error adding contract to group', err)
-        return err
-      })
-  }
+  // create new contract document in groupContracts collection
+  const contractDoc = doc(groupContracts(group.id), contract.id)
+  await setDoc(contractDoc, {
+    contractId: contract.id,
+    createdTime: Date.now(),
+  })
 }
 
 export async function removeContractFromGroup(
   group: Group,
-  contract: Contract,
-  userId: string
+  contract: Contract
 ) {
-  if (!canModifyGroupContracts(group, userId)) return
-
   if (contract.groupLinks?.map((l) => l.groupId).includes(group.id)) {
     const newGroupLinks = contract.groupLinks?.filter(
       (link) => link.slug !== group.slug
@@ -188,25 +205,9 @@ export async function removeContractFromGroup(
     })
   }
 
-  if (group.contractIds.includes(contract.id)) {
-    const newContractIds = group.contractIds.filter((id) => id !== contract.id)
-    return await updateGroup(group, {
-      contractIds: uniq(newContractIds),
-    })
-      .then(() => group)
-      .catch((err) => {
-        console.error('error removing contract from group', err)
-        return err
-      })
-  }
-}
-
-export function canModifyGroupContracts(group: Group, userId: string) {
-  return (
-    group.creatorId === userId ||
-    group.memberIds.includes(userId) ||
-    group.anyoneCanJoin
-  )
+  // delete the contract document in groupContracts collection
+  const contractDoc = doc(groupContracts(group.id), contract.id)
+  await deleteDoc(contractDoc)
 }
 
 export function getGroupLinkToDisplay(contract: Contract) {
@@ -222,3 +223,8 @@ export function getGroupLinkToDisplay(contract: Contract) {
     : sortedGroupLinks?.[0] ?? null
   return groupToDisplay
 }
+
+export async function listMembers(group: Group) {
+  const members = await getValues<GroupMemberDoc>(groupMembers(group.id))
+  return await Promise.all(members.map((m) => m.userId).map(getUser))
+}
diff --git a/web/pages/create.tsx b/web/pages/create.tsx
index 23a88ec0..b5892ccf 100644
--- a/web/pages/create.tsx
+++ b/web/pages/create.tsx
@@ -20,7 +20,7 @@ import {
 import { formatMoney } from 'common/util/format'
 import { removeUndefinedProps } from 'common/util/object'
 import { ChoicesToggleGroup } from 'web/components/choices-toggle-group'
-import { canModifyGroupContracts, getGroup } from 'web/lib/firebase/groups'
+import { getGroup } from 'web/lib/firebase/groups'
 import { Group } from 'common/group'
 import { useTracking } from 'web/hooks/use-tracking'
 import { useWarnUnsavedChanges } from 'web/hooks/use-warn-unsaved-changes'
@@ -139,7 +139,7 @@ export function NewContract(props: {
   useEffect(() => {
     if (groupId)
       getGroup(groupId).then((group) => {
-        if (group && canModifyGroupContracts(group, creator.id)) {
+        if (group) {
           setSelectedGroup(group)
           setShowGroupSelector(false)
         }
diff --git a/web/pages/group/[...slugs]/index.tsx b/web/pages/group/[...slugs]/index.tsx
index 9012b585..4626aa77 100644
--- a/web/pages/group/[...slugs]/index.tsx
+++ b/web/pages/group/[...slugs]/index.tsx
@@ -14,13 +14,14 @@ import {
   getGroupBySlug,
   groupPath,
   joinGroup,
+  listMembers,
   updateGroup,
 } from 'web/lib/firebase/groups'
 import { Row } from 'web/components/layout/row'
 import { firebaseLogin, getUser, User } from 'web/lib/firebase/users'
 import { Col } from 'web/components/layout/col'
 import { useUser } from 'web/hooks/use-user'
-import { listMembers, useGroup, useMembers } from 'web/hooks/use-group'
+import { useGroup, useGroupContractIds, useMembers } from 'web/hooks/use-group'
 import { scoreCreators, scoreTraders } from 'common/scoring'
 import { Leaderboard } from 'web/components/leaderboard'
 import { formatMoney } from 'common/util/format'
@@ -157,7 +158,6 @@ export default function GroupPage(props: {
   const {
     contractsCount,
     creator,
-    members,
     traderScores,
     topTraders,
     creatorScores,
@@ -174,6 +174,7 @@ export default function GroupPage(props: {
 
   const user = useUser()
   const isAdmin = useAdmin()
+  const members = useMembers(group?.id) ?? props.members
 
   useSaveReferral(user, {
     defaultReferrerUsername: creator.username,
@@ -183,9 +184,8 @@ export default function GroupPage(props: {
   if (group === null || !groupSubpages.includes(page) || slugs[2]) {
     return <Custom404 />
   }
-  const { memberIds } = group
   const isCreator = user && group && user.id === group.creatorId
-  const isMember = user && memberIds.includes(user.id)
+  const isMember = user && members.map((m) => m.id).includes(user.id)
 
   const leaderboard = (
     <Col>
@@ -347,8 +347,7 @@ function GroupOverview(props: {
           {isCreator ? (
             <EditGroupButton className={'ml-1'} group={group} />
           ) : (
-            user &&
-            group.memberIds.includes(user?.id) && (
+            user && (
               <Row>
                 <JoinOrLeaveGroupButton group={group} />
               </Row>
@@ -425,7 +424,7 @@ function GroupMemberSearch(props: { members: User[]; group: Group }) {
   let { members } = props
 
   // Use static members on load, but also listen to member changes:
-  const listenToMembers = useMembers(group)
+  const listenToMembers = useMembers(group.id)
   if (listenToMembers) {
     members = listenToMembers
   }
@@ -547,6 +546,7 @@ function AddContractButton(props: { group: Group; user: User }) {
   const [open, setOpen] = useState(false)
   const [contracts, setContracts] = useState<Contract[]>([])
   const [loading, setLoading] = useState(false)
+  const groupContractIds = useGroupContractIds(group.id)
 
   async function addContractToCurrentGroup(contract: Contract) {
     if (contracts.map((c) => c.id).includes(contract.id)) {
@@ -634,7 +634,9 @@ function AddContractButton(props: { group: Group; user: User }) {
               hideOrderSelector={true}
               onContractClick={addContractToCurrentGroup}
               cardHideOptions={{ hideGroupLink: true, hideQuickBet: true }}
-              additionalFilter={{ excludeContractIds: group.contractIds }}
+              additionalFilter={{
+                excludeContractIds: groupContractIds,
+              }}
               highlightOptions={{
                 contractIds: contracts.map((c) => c.id),
                 highlightClassName: '!bg-indigo-100 border-indigo-100 border-2',
@@ -653,7 +655,7 @@ function JoinGroupButton(props: {
 }) {
   const { group, user } = props
   function addUserToGroup() {
-    if (user && !group.memberIds.includes(user.id)) {
+    if (user) {
       toast.promise(joinGroup(group, user.id), {
         loading: 'Joining group...',
         success: 'Joined group!',
diff --git a/web/pages/groups.tsx b/web/pages/groups.tsx
index 9ef2d8ff..dfb19c69 100644
--- a/web/pages/groups.tsx
+++ b/web/pages/groups.tsx
@@ -7,7 +7,12 @@ import { Col } from 'web/components/layout/col'
 import { Row } from 'web/components/layout/row'
 import { Page } from 'web/components/page'
 import { Title } from 'web/components/title'
-import { useGroups, useMemberGroupIds, useMembers } from 'web/hooks/use-group'
+import {
+  useGroupContractIds,
+  useGroups,
+  useMemberGroupIds,
+  useMemberIds,
+} from 'web/hooks/use-group'
 import { useUser } from 'web/hooks/use-user'
 import { groupPath, listAllGroups } from 'web/lib/firebase/groups'
 import { getUser, User } from 'web/lib/firebase/users'
@@ -18,7 +23,6 @@ import { Avatar } from 'web/components/avatar'
 import { JoinOrLeaveGroupButton } from 'web/components/groups/groups-button'
 import { searchInAny } from 'common/util/parse'
 import { SEO } from 'web/components/SEO'
-import { UserLink } from 'web/components/user-link'
 
 export async function getStaticProps() {
   let groups = await listAllGroups().catch((_) => [])
@@ -73,10 +77,7 @@ export default function Groups(props: {
 
   // List groups with the highest question count, then highest member count
   // TODO use find-active-contracts to sort by?
-  const matches = sortBy(groups, [
-    (group) => -1 * group.contractIds.length,
-    (group) => -1 * group.memberIds.length,
-  ]).filter((g) =>
+  const matches = sortBy(groups, []).filter((g) =>
     searchInAny(
       query,
       g.name,
@@ -87,10 +88,7 @@ export default function Groups(props: {
 
   const matchesOrderedByRecentActivity = sortBy(groups, [
     (group) =>
-      -1 *
-      (group.mostRecentChatActivityTime ??
-        group.mostRecentContractAddedTime ??
-        group.mostRecentActivityTime),
+      -1 * (group.mostRecentContractAddedTime ?? group.mostRecentActivityTime),
   ]).filter((g) =>
     searchInAny(
       query,
@@ -124,37 +122,6 @@ export default function Groups(props: {
           <Tabs
             currentPageForAnalytics={'groups'}
             tabs={[
-              ...(user && memberGroupIds.length > 0
-                ? [
-                    {
-                      title: 'My Groups',
-                      content: (
-                        <Col>
-                          <input
-                            type="text"
-                            onChange={(e) => debouncedQuery(e.target.value)}
-                            placeholder="Search your groups"
-                            className="input input-bordered mb-4 w-full"
-                          />
-
-                          <div className="flex flex-wrap justify-center gap-4">
-                            {matchesOrderedByRecentActivity
-                              .filter((match) =>
-                                memberGroupIds.includes(match.id)
-                              )
-                              .map((group) => (
-                                <GroupCard
-                                  key={group.id}
-                                  group={group}
-                                  creator={creatorsDict[group.creatorId]}
-                                />
-                              ))}
-                          </div>
-                        </Col>
-                      ),
-                    },
-                  ]
-                : []),
               {
                 title: 'All',
                 content: (
@@ -178,6 +145,31 @@ export default function Groups(props: {
                   </Col>
                 ),
               },
+              {
+                title: 'My Groups',
+                content: (
+                  <Col>
+                    <input
+                      type="text"
+                      onChange={(e) => debouncedQuery(e.target.value)}
+                      placeholder="Search your groups"
+                      className="input input-bordered mb-4 w-full"
+                    />
+
+                    <div className="flex flex-wrap justify-center gap-4">
+                      {matchesOrderedByRecentActivity
+                        .filter((match) => memberGroupIds.includes(match.id))
+                        .map((group) => (
+                          <GroupCard
+                            key={group.id}
+                            group={group}
+                            creator={creatorsDict[group.creatorId]}
+                          />
+                        ))}
+                    </div>
+                  </Col>
+                ),
+              },
             ]}
           />
         </Col>
@@ -188,6 +180,7 @@ export default function Groups(props: {
 
 export function GroupCard(props: { group: Group; creator: User | undefined }) {
   const { group, creator } = props
+  const groupContracts = useGroupContractIds(group.id)
   return (
     <Col className="relative min-w-[20rem]  max-w-xs gap-1 rounded-xl bg-white p-8 shadow-md hover:bg-gray-100">
       <Link href={groupPath(group.slug)}>
@@ -205,7 +198,7 @@ export function GroupCard(props: { group: Group; creator: User | undefined }) {
       <Row className="items-center justify-between gap-2">
         <span className="text-xl">{group.name}</span>
       </Row>
-      <Row>{group.contractIds.length} questions</Row>
+      <Row>{groupContracts.length} questions</Row>
       <Row className="text-sm text-gray-500">
         <GroupMembersList group={group} />
       </Row>
@@ -221,23 +214,11 @@ export function GroupCard(props: { group: Group; creator: User | undefined }) {
 
 function GroupMembersList(props: { group: Group }) {
   const { group } = props
-  const maxMembersToShow = 3
-  const members = useMembers(group, maxMembersToShow).filter(
-    (m) => m.id !== group.creatorId
-  )
-  if (group.memberIds.length === 1) return <div />
+  const memberIds = useMemberIds(group.id)
+  if (memberIds.length === 1) return <div />
   return (
     <div className="text-neutral flex flex-wrap gap-1">
-      <span className={'text-gray-500'}>Other members</span>
-      {members.slice(0, maxMembersToShow).map((member, i) => (
-        <div key={member.id} className={'flex-shrink'}>
-          <UserLink name={member.name} username={member.username} />
-          {members.length > 1 && i !== members.length - 1 && <span>,</span>}
-        </div>
-      ))}
-      {group.memberIds.length > maxMembersToShow && (
-        <span> & {group.memberIds.length - maxMembersToShow} more</span>
-      )}
+      <span>{memberIds.length} members</span>
     </div>
   )
 }
diff --git a/web/pages/tournaments/index.tsx b/web/pages/tournaments/index.tsx
index b1f84473..9bfdfb89 100644
--- a/web/pages/tournaments/index.tsx
+++ b/web/pages/tournaments/index.tsx
@@ -122,7 +122,7 @@ export async function getStaticProps() {
   const markets = Object.fromEntries(groups.map((g, i) => [g.id, contracts[i]]))
 
   const groupMap = keyBy(groups, 'id')
-  const numPeople = mapValues(groupMap, (g) => g?.memberIds.length)
+  const numPeople = mapValues(groupMap, (g) => g?.totalMembers)
   const slugs = mapValues(groupMap, 'slug')
 
   return { props: { markets, numPeople, slugs }, revalidate: 60 * 10 }