diff --git a/functions/src/scripts/migrate-rich-text.ts b/functions/src/scripts/migrate-rich-text.ts
new file mode 100644
index 00000000..d1d9d22c
--- /dev/null
+++ b/functions/src/scripts/migrate-rich-text.ts
@@ -0,0 +1,113 @@
+// We have three kinds of rich text:
+// - Contract descriptions.
+// - Comment text.
+// - Post contents.
+// These are stored in two different ways:
+// - As plaintext strings.
+// - As structured ProseMirror JSON in Firestore.
+// We want to make all of these into:
+// - Strings containing serialized ProseMirror JSON.
+
+import * as admin from 'firebase-admin'
+import { FieldValue } from 'firebase-admin/firestore'
+import { initAdmin } from './script-init'
+import { log, writeAsync } from '../utils'
+import { filterDefined } from '../../../common/util/array'
+import { plainTextToProseMirror } from '../../../common/util/parse'
+
+initAdmin()
+const firestore = admin.firestore()
+
+const isValidJSON = (s: string) => {
+  try {
+    JSON.parse(s)
+    return true
+  } catch {
+    return false
+  }
+}
+
+const migrateContractDescriptions = async () => {
+  const contractQ = await firestore.collection('contracts').get()
+  console.log(`Loaded ${contractQ.size} contracts.`)
+  const updates = filterDefined(
+    contractQ.docs.map((doc) => {
+      const fields: { [k: string]: unknown } = {}
+      const oldDescription = doc.get('description')
+      if (typeof oldDescription === 'string') {
+        if (isValidJSON(oldDescription)) {
+          // this one is already good
+          return null
+        } else {
+          fields.description = JSON.stringify(
+            plainTextToProseMirror(oldDescription)
+          )
+        }
+      } else if (oldDescription != null) {
+        // already JSON, just need to serialize into string
+        fields.description = JSON.stringify(oldDescription)
+      } else {
+        throw new Error('Content had null description for some reason.')
+      }
+      return { doc: doc.ref, fields }
+    })
+  )
+  log(`Found ${updates.length} contracts with old format descriptions.`)
+  await writeAsync(firestore, updates)
+}
+
+const migrateCommentContents = async () => {
+  const commentQ = await firestore.collectionGroup('comments').get()
+  console.log(`Loaded ${commentQ.size} comments.`)
+  const updates = filterDefined(
+    commentQ.docs.map((doc) => {
+      const fields: { [k: string]: unknown } = {}
+      const oldText = doc.get('text')
+      const oldContent = doc.get('content')
+      if (typeof oldContent === 'string') {
+        // this one is already good
+        return null
+      } else if (oldContent != null) {
+        // already JSON, just need to serialize into string
+        fields.content = JSON.stringify(oldContent)
+      } else if (oldText != null) {
+        fields.text = FieldValue.delete()
+        fields.content = JSON.stringify(plainTextToProseMirror(oldText))
+      } else {
+        throw new Error('Comment mysteriously had neither text nor content.')
+      }
+      return { doc: doc.ref, fields }
+    })
+  )
+  log(`Found ${updates.length} comments with old format content.`)
+  await writeAsync(firestore, updates)
+}
+
+const migratePostContents = async () => {
+  const postQ = await firestore.collection('posts').get()
+  console.log(`Loaded ${postQ.size} posts.`)
+  const updates = filterDefined(
+    postQ.docs.map((doc) => {
+      const fields: { [k: string]: unknown } = {}
+      const oldContent = doc.get('content')
+      if (typeof oldContent === 'string') {
+        // this one is already good
+        return null
+      } else if (oldContent != null) {
+        // already JSON, just need to serialize into string
+        fields.content = JSON.stringify(oldContent)
+      } else {
+        throw new Error('Post had null content for some reason.')
+      }
+      return { doc: doc.ref, fields }
+    })
+  )
+  log(`Found ${updates.length} posts with old format content.`)
+  await writeAsync(firestore, updates)
+}
+
+if (require.main === module) {
+  migrateContractDescriptions()
+  migrateCommentContents()
+  migratePostContents()
+}