diff --git a/web/components/contract-feed.tsx b/web/components/contract-feed.tsx
index 5a3be62f..bf5885b5 100644
--- a/web/components/contract-feed.tsx
+++ b/web/components/contract-feed.tsx
@@ -25,7 +25,7 @@ import {
 import { useUser } from '../hooks/use-user'
 import { Linkify } from './linkify'
 import { Row } from './layout/row'
-import { createComment } from '../lib/firebase/comments'
+import { createComment, MAX_COMMENT_LENGTH } from '../lib/firebase/comments'
 import { useComments } from '../hooks/use-comments'
 import { formatMoney } from '../../common/util/format'
 import { ResolutionOrChance } from './contract-card'
@@ -135,6 +135,7 @@ function FeedBet(props: { activityItem: any; feedType: FeedType }) {
                 className="textarea textarea-bordered w-full"
                 placeholder="Add a comment..."
                 rows={3}
+                maxLength={MAX_COMMENT_LENGTH}
                 onKeyDown={(e) => {
                   if (e.key === 'Enter' && (e.ctrlKey || e.metaKey)) {
                     submitComment()
diff --git a/web/lib/firebase/comments.ts b/web/lib/firebase/comments.ts
index 34e4bcfe..dfb9a01d 100644
--- a/web/lib/firebase/comments.ts
+++ b/web/lib/firebase/comments.ts
@@ -14,6 +14,8 @@ import { User } from '../../../common/user'
 import { Comment } from '../../../common/comment'
 export type { Comment }
 
+export const MAX_COMMENT_LENGTH = 10000
+
 export async function createComment(
   contractId: string,
   betId: string,
@@ -27,7 +29,7 @@ export async function createComment(
     contractId,
     betId,
     userId: commenter.id,
-    text,
+    text: text.slice(0, MAX_COMMENT_LENGTH),
     createdTime: Date.now(),
     userName: commenter.name,
     userUsername: commenter.username,