Support replies in your app built with XMTP

Use the reply content type to support quote replies in your app. A reply is a method to directly respond to a specific message in a conversation. Users can select and reply to a particular message instead of sending a new one.

Use a local database for performance

Use a local database to store replies. This will enable your app to performantly display a reply with its referenced message when rendering message lists.

To learn more about using a local database, see Use local-first architecture.

Configure the content type

In some SDKs, the ReplyCodec is already included in the SDK. If not, you can install the package using the following command:

In the JavaScript SDK, you need to import this package first.

Bash

npm i @xmtp/content-type-reply

After importing the package, you can register the codec.

JavaScript

import { ContentTypeReply, ReplyCodec } from "@xmtp/content-type-reply";
// Create the XMTP client
const xmtp = await Client.create(signer, { env: "dev" });
xmtp.registerCodec(new ReplyCodec());

Send a reply

Once you've created a reply, you can send it. Replies are represented as objects with two keys:

reference: ID of the message being replied to
content: String representation of the reply

JavaScript

import { ContentTypeText } from "@xmtp/content-type-text";
import { ContentTypeReply } from "@xmtp/content-type-reply";
import type { Reply } from "@xmtp/content-type-reply";
 
const reply: Reply = {
  reference: someMessageID,
  contentType: ContentTypeText
  content: "I concur",
};
 
await conversation.send(reply, {
  contentType: ContentTypeReply,
});

Receive the content type

JavaScript

if (message.contentType.sameAs(ContentTypeReply)) {
  // We've got a reply.
  const reply: Reply = message.content;
}

To handle unsupported content types, refer to the fallback section.

Display the reply

How you choose to display replies in your app is up to you. It might be useful to look at the user experience for replies in popular apps such as Telegram and Discord. For example, in Discord, users can reply to individual messages, and the reply provides a link to the original message.

Note that the user experience of replies in iMessage and Slack follows more of a threaded pattern, where messages display in logical groupings, or threads. This reply content type doesn't support the threaded pattern. If you'd like to request support for a threaded reply pattern, post an XIP idea.