diff --git a/js/conversation_controller.js b/js/conversation_controller.js
index 127e2946cf4..e0bcb33dbaa 100644
--- a/js/conversation_controller.js
+++ b/js/conversation_controller.js
@@ -8,6 +8,8 @@
 
   window.Whisper = window.Whisper || {};
 
+  const MAX_MESSAGE_BODY_LENGTH = 64 * 1024;
+
   const conversations = new Whisper.ConversationCollection();
   const inboxCollection = new (Backbone.Collection.extend({
     initialize() {
@@ -183,12 +185,25 @@
 
           this._initialFetchComplete = true;
           await Promise.all(
-            conversations.map(conversation => {
+            conversations.map(async conversation => {
               if (!conversation.get('lastMessage')) {
-                return conversation.updateLastMessage();
+                await conversation.updateLastMessage();
               }
 
-              return null;
+              // In case a too-large draft was saved to the database
+              const draft = conversation.get('draft');
+              if (draft && draft.length > MAX_MESSAGE_BODY_LENGTH) {
+                this.model.set({
+                  draft: draft.slice(0, MAX_MESSAGE_BODY_LENGTH),
+                });
+                await window.Signal.Data.updateConversation(
+                  conversation.id,
+                  conversation.attributes,
+                  {
+                    Conversation: Whisper.Conversation,
+                  }
+                );
+              }
             })
           );
           window.log.info('ConversationController: done with initial fetch');
diff --git a/js/views/conversation_view.js b/js/views/conversation_view.js
index 0ed600dbfe3..1fcbb131708 100644
--- a/js/views/conversation_view.js
+++ b/js/views/conversation_view.js
@@ -323,6 +323,7 @@
         onSubmit: message => this.sendMessage(message),
         onEditorStateChange: (msg, caretLocation) =>
           this.onEditorStateChange(msg, caretLocation),
+        onTextTooLong: () => this.showToast(Whisper.MessageBodyTooLongToast),
         onChooseAttachment: this.onChooseAttachment.bind(this),
         micCellEl,
         attachmentListEl,
diff --git a/ts/components/CompositionArea.tsx b/ts/components/CompositionArea.tsx
index 8ab0920cc5a..6d83d1a21a0 100644
--- a/ts/components/CompositionArea.tsx
+++ b/ts/components/CompositionArea.tsx
@@ -38,7 +38,11 @@ export type OwnProps = {
 
 export type Props = Pick<
   CompositionInputProps,
-  'onSubmit' | 'onEditorSizeChange' | 'onEditorStateChange' | 'startingText'
+  | 'onSubmit'
+  | 'onEditorSizeChange'
+  | 'onEditorStateChange'
+  | 'onTextTooLong'
+  | 'startingText'
 > &
   Pick<
     EmojiButtonProps,
@@ -76,6 +80,7 @@ export const CompositionArea = ({
   compositionApi,
   onEditorSizeChange,
   onEditorStateChange,
+  onTextTooLong,
   startingText,
   // EmojiButton
   onPickEmoji,
@@ -336,6 +341,7 @@ export const CompositionArea = ({
             onSubmit={handleSubmit}
             onEditorSizeChange={onEditorSizeChange}
             onEditorStateChange={onEditorStateChange}
+            onTextTooLong={onTextTooLong}
             onDirtyChange={setDirty}
             skinTone={skinTone}
             startingText={startingText}
diff --git a/ts/components/CompositionInput.tsx b/ts/components/CompositionInput.tsx
index d0b129f6d62..7645162244f 100644
--- a/ts/components/CompositionInput.tsx
+++ b/ts/components/CompositionInput.tsx
@@ -29,6 +29,7 @@ import {
 } from './emoji/lib';
 import { LocalizerType } from '../types/Util';
 
+const MAX_LENGTH = 64 * 1024;
 const colonsRegex = /(?:^|\s):[a-z0-9-_+]+:?/gi;
 const triggerEmojiRegex = /^(?:[-+]\d|[a-z]{2})/i;
 
@@ -43,6 +44,7 @@ export type Props = {
   onDirtyChange?(dirty: boolean): unknown;
   onEditorStateChange?(messageText: string, caretLocation: number): unknown;
   onEditorSizeChange?(rect: ContentRect): unknown;
+  onTextTooLong(): unknown;
   onPickEmoji(o: EmojiPickDataType): unknown;
   onSubmit(message: string): unknown;
 };
@@ -78,6 +80,43 @@ function getTrimmedMatchAtIndex(str: string, index: number, pattern: RegExp) {
   return null;
 }
 
+function getLengthOfSelectedText(state: EditorState): number {
+  const currentSelection = state.getSelection();
+  let length = 0;
+
+  const currentContent = state.getCurrentContent();
+  const startKey = currentSelection.getStartKey();
+  const endKey = currentSelection.getEndKey();
+  const startBlock = currentContent.getBlockForKey(startKey);
+  const isStartAndEndBlockAreTheSame = startKey === endKey;
+  const startBlockTextLength = startBlock.getLength();
+  const startSelectedTextLength =
+    startBlockTextLength - currentSelection.getStartOffset();
+  const endSelectedTextLength = currentSelection.getEndOffset();
+  const keyAfterEnd = currentContent.getKeyAfter(endKey);
+
+  if (isStartAndEndBlockAreTheSame) {
+    length +=
+      currentSelection.getEndOffset() - currentSelection.getStartOffset();
+  } else {
+    let currentKey = startKey;
+
+    while (currentKey && currentKey !== keyAfterEnd) {
+      if (currentKey === startKey) {
+        length += startSelectedTextLength + 1;
+      } else if (currentKey === endKey) {
+        length += endSelectedTextLength;
+      } else {
+        length += currentContent.getBlockForKey(currentKey).getLength() + 1;
+      }
+
+      currentKey = currentContent.getKeyAfter(currentKey);
+    }
+  }
+
+  return length;
+}
+
 function getWordAtIndex(str: string, index: number) {
   const start = str
     .slice(0, index + 1)
@@ -172,6 +211,7 @@ export const CompositionInput = ({
   onDirtyChange,
   onEditorStateChange,
   onEditorSizeChange,
+  onTextTooLong,
   onPickEmoji,
   onSubmit,
   skinTone,
@@ -298,6 +338,51 @@ export const CompositionInput = ({
     ]
   );
 
+  const handleBeforeInput = React.useCallback(
+    (): DraftHandleValue => {
+      if (!editorStateRef.current) {
+        return 'not-handled';
+      }
+
+      const editorState = editorStateRef.current;
+      const plainText = editorState.getCurrentContent().getPlainText();
+      const selectedTextLength = getLengthOfSelectedText(editorState);
+
+      if (plainText.length - selectedTextLength > MAX_LENGTH - 1) {
+        onTextTooLong();
+
+        return 'handled';
+      }
+
+      return 'not-handled';
+    },
+    [onTextTooLong, editorStateRef]
+  );
+
+  const handlePastedText = React.useCallback(
+    (pastedText: string): DraftHandleValue => {
+      if (!editorStateRef.current) {
+        return 'not-handled';
+      }
+
+      const editorState = editorStateRef.current;
+      const plainText = editorState.getCurrentContent().getPlainText();
+      const selectedTextLength = getLengthOfSelectedText(editorState);
+
+      if (
+        plainText.length + pastedText.length - selectedTextLength >
+        MAX_LENGTH
+      ) {
+        onTextTooLong();
+
+        return 'handled';
+      }
+
+      return 'not-handled';
+    },
+    [onTextTooLong, editorStateRef]
+  );
+
   const resetEditorState = React.useCallback(
     () => {
       const newEmptyState = EditorState.createEmpty(compositeDecorator);
@@ -694,6 +779,8 @@ export const CompositionInput = ({
                     onEscape={handleEscapeKey}
                     onTab={onTab}
                     handleKeyCommand={handleEditorCommand}
+                    handleBeforeInput={handleBeforeInput}
+                    handlePastedText={handlePastedText}
                     keyBindingFn={editorKeybindingFn}
                     spellCheck={true}
                     stripPastedStyles={true}
diff --git a/ts/util/lint/exceptions.json b/ts/util/lint/exceptions.json
index 0ba7a221427..74107b39cf4 100644
--- a/ts/util/lint/exceptions.json
+++ b/ts/util/lint/exceptions.json
@@ -164,7 +164,7 @@
     "rule": "jQuery-load(",
     "path": "js/conversation_controller.js",
     "line": "    async load() {",
-    "lineNumber": 169,
+    "lineNumber": 171,
     "reasonCategory": "falseMatch",
     "updated": "2019-07-31T00:19:18.696Z"
   },
@@ -172,7 +172,7 @@
     "rule": "jQuery-load(",
     "path": "js/conversation_controller.js",
     "line": "      this._initialPromise = load();",
-    "lineNumber": 204,
+    "lineNumber": 219,
     "reasonCategory": "falseMatch",
     "updated": "2019-07-31T00:19:18.696Z"
   },
@@ -7475,7 +7475,7 @@
     "rule": "DOM-innerHTML",
     "path": "ts/components/CompositionArea.tsx",
     "line": "  el.innerHTML = '';",
-    "lineNumber": 65,
+    "lineNumber": 69,
     "reasonCategory": "usageTrusted",
     "updated": "2019-08-01T14:10:37.481Z",
     "reasonDetail": "Our code, no user input, only clearing out the dom"