diff --git a/functions/src/emails.ts b/functions/src/emails.ts
index 3dd0873f..a7ca2845 100644
--- a/functions/src/emails.ts
+++ b/functions/src/emails.ts
@@ -1,9 +1,7 @@
-import * as admin from 'firebase-admin'
-
 import { Contract } from '../../common/contract'
 import { User } from '../../common/user'
 import { sendTemplateEmail } from './send-email'
-import { getUser } from './utils'
+import { getPrivateUser, getUser } from './utils'
 
 type market_resolved_template = {
   name: string
@@ -21,13 +19,17 @@ export const sendMarketResolutionEmail = async (
   contract: Contract,
   resolution: 'YES' | 'NO' | 'CANCEL' | 'MKT'
 ) => {
+  const privateUser = await getPrivateUser(userId)
+  if (
+    !privateUser ||
+    privateUser.unsubscribedFromResolutionEmails ||
+    !privateUser.email
+  )
+    return
+
   const user = await getUser(userId)
   if (!user) return
 
-  const fbUser = await admin.auth().getUser(userId)
-  const email = fbUser.email
-  if (!email) return
-
   const outcome = toDisplayResolution[resolution]
 
   const subject = `Resolved ${outcome}: ${contract.question}`
@@ -45,7 +47,12 @@ export const sendMarketResolutionEmail = async (
   // https://app.mailgun.com/app/sending/domains/mg.manifold.markets/templates/edit/market-resolved/initial
   // Mailgun username: james@mantic.markets
 
-  await sendTemplateEmail(email, subject, 'market-resolved', templateData)
+  await sendTemplateEmail(
+    privateUser.email,
+    subject,
+    'market-resolved',
+    templateData
+  )
 }
 
 const toDisplayResolution = { YES: 'YES', NO: 'NO', CANCEL: 'N/A', MKT: 'MKT' }
diff --git a/functions/src/index.ts b/functions/src/index.ts
index 534e72cf..0b4ef72c 100644
--- a/functions/src/index.ts
+++ b/functions/src/index.ts
@@ -10,5 +10,6 @@ export * from './stripe'
 export * from './sell-bet'
 export * from './create-contract'
 export * from './create-user'
+export * from './unsubscribe'
 export * from './update-contract-metrics'
 export * from './update-user-metrics'
diff --git a/functions/src/unsubscribe.ts b/functions/src/unsubscribe.ts
new file mode 100644
index 00000000..d556f4ba
--- /dev/null
+++ b/functions/src/unsubscribe.ts
@@ -0,0 +1,33 @@
+import * as functions from 'firebase-functions'
+import * as admin from 'firebase-admin'
+import * as _ from 'lodash'
+import { getPrivateUser } from './utils'
+import { PrivateUser } from '../../common/user'
+
+export const unsubscribe = functions
+  .runWith({ minInstances: 1 })
+  .https.onRequest(async (req, res) => {
+    let id = req.query.id as string
+    if (!id) return
+
+    let privateUser = await getPrivateUser(id)
+
+    if (privateUser) {
+      let { username } = privateUser
+
+      const update: Partial<PrivateUser> = {
+        unsubscribedFromResolutionEmails: true,
+      }
+
+      await firestore.collection('private-users').doc(id).update(update)
+
+      res.send(
+        username +
+          ', you have been unsubscribed from market resolution emails on Manifold Markets.'
+      )
+    } else {
+      res.send('This user is not currently subscribed or does not exist.')
+    }
+  })
+
+const firestore = admin.firestore()
diff --git a/functions/src/utils.ts b/functions/src/utils.ts
index e6ecd7cf..1a52d116 100644
--- a/functions/src/utils.ts
+++ b/functions/src/utils.ts
@@ -1,7 +1,7 @@
 import * as admin from 'firebase-admin'
 
 import { Contract } from '../../common/contract'
-import { User } from '../../common/user'
+import { PrivateUser, User } from '../../common/user'
 
 export const getValue = async <T>(collection: string, doc: string) => {
   const snap = await admin.firestore().collection(collection).doc(doc).get()
@@ -22,6 +22,10 @@ export const getUser = (userId: string) => {
   return getValue<User>('users', userId)
 }
 
+export const getPrivateUser = (userId: string) => {
+  return getValue<PrivateUser>('private-users', userId)
+}
+
 export const getUserByUsername = async (username: string) => {
   const snap = await firestore
     .collection('users')