Messages Overview

Messages are the core building blocks of a chat application. This page covers sending, retrieving, updating, and deleting messages, as well as how Stream processes and formats message content.

Sending a Message

To send a message to a channel, use the sendMessage method:

const message = await channel.sendMessage({
  text: "Hello, world!",
});

Server-side SDKs require a user_id parameter to specify who is sending the message. Client-side SDKs set this automatically based on the connected user.

Message Parameters

NameTypeDescriptionDefaultOptional
textstringThe message text. Supports markdown and automatic URL enrichment.
attachmentsarrayA list of attachments (audio, video, image, text). Maximum 30 attachments per message with a combined size limit of 5KB.
user_idobjectRequired for server-side SDKs. Set automatically in client-side mode.
mentioned_usersarrayA list of user IDs mentioned in the message. You receive back the full user data in the response. Maximum 25 users.
custom dataobjectExtra data for the message. Must not exceed 5KB in size.
skip_pushboolIf true, do not send a push notification for this message.false
restricted_visibilityarraySend the message only to specific channel members, identified by their user IDs.

Sending Messages with Attachments

Messages can include attachments such as images, videos, audio files, and custom content. The following example shows how to send a message with an image attachment and user mentions:

const message = await channel.sendMessage(
  {
    text: "@Josh Check out this image!",
    attachments: [
      {
        type: "image",
        asset_url: "https://bit.ly/2K74TaG",
        thumb_url: "https://bit.ly/2Uumxti",
        myCustomField: 123,
      },
    ],
    mentioned_users: [josh.id],
    priority: "high",
  },
  { skip_push: true },
);

Supported Attachment Types

Stream’s UI components support the following attachment types by default:

  • Audio: Audio files and recordings
  • Video: Video files
  • Image: Photos and images
  • Text: Text-based attachments

You can define custom attachment types as long as you implement the frontend rendering logic to handle them. Common use cases include embedding products (with photos, descriptions, and links) or sharing user locations.

The React tutorial explains how to customize the Attachment component.

Message Processing

When you send a message, Stream performs several processing steps:

  1. Markdown parsing: The message text is parsed for markdown formatting.
  2. URL enrichment: The first URL in the message text is scraped for Open Graph data, adding preview information automatically.
  3. Slash commands: Commands like /giphy, /ban, and /flag are processed and executed.

URL Enrichment

When a message contains a URL, Stream automatically scrapes the page for Open Graph metadata and creates an attachment with the preview information:

const response = await channel.sendMessage({
  text: "Check this out https://imgur.com/r/bears/4zmGbMN",
});

The resulting message includes an automatically generated attachment:

{
  "id": "message-id",
  "text": "Check this out https://imgur.com/r/bears/4zmGbMN",
  "attachments": [
    {
      "type": "image",
      "author_name": "Imgur",
      "title": "An update: Dushi made it safe to Bear Sanctuary",
      "title_link": "https://imgur.com/4zmGbMN",
      "text": "1678 views on Imgur",
      "image_url": "https://i.imgur.com/4zmGbMN.jpg?fb",
      "thumb_url": "https://i.imgur.com/4zmGbMN.jpg?fb",
      "og_scrape_url": "https://imgur.com/r/bears/4zmGbMN"
    }
  ]
}

URL Attachment Fields

NameTypeDescription
typestringThe attachment type based on the URL resource: audio, image, or video
author_namestringThe name of the author
titlestringThe attachment title
title_linkstringThe link the attachment points to
textstringThe attachment description text
image_urlstringThe URL to the attached image
thumb_urlstringThe URL to the attachment thumbnail
asset_urlstringThe URL to the audio, video, or image resource
og_scrape_urlstringThe original URL that was scraped

The Open Graph scraper uses this user agent: getstream.io/opengraph-bot facebookexternalhit/1.1. If you control the target website, ensure this user agent is not blocked for optimal results.

Message Response Structure

The API returns a message object containing all information about the message, including the author, attachments, reactions, and metadata.

Message Fields

Field NameDescription
idUnique message identifier. Maximum 255 characters; cannot contain , or %.
textThe raw message text
htmlSafe HTML generated from the text. Can only be set via server-side APIs or import.
typeMessage type: regular, ephemeral, error, reply, system, or deleted
cidThe channel ID in the format type:id
userThe author user object
attachmentsList of attachments (maximum 30)
mentioned_usersUsers mentioned in the message
reaction_countsReaction counts by type (deprecated, use reaction_groups)
reaction_scoresReaction scores by type
reaction_groupsReaction statistics grouped by type with count, scores, and timestamps
latest_reactionsThe 10 most recent reactions
own_reactionsReactions added by the current user
reply_countNumber of replies to this message
thread_participantsUsers who have participated in the thread
parent_idID of the parent message if this is a reply
quoted_message_idID of a quoted message
pinnedWhether the message is pinned
pinned_atWhen the message was pinned
pinned_byUser who pinned the message
pin_expiresWhen the pin expires (null for no expiration)
silentWhether this is a silent message (no push notifications)
created_atWhen the message was created
updated_atWhen the message was last updated
deleted_atWhen the message was deleted
message_text_updated_atWhen the message text was last updated

Message Types

TypeDescription
regularA standard message posted to the channel. This is the default type.
ephemeralA temporary message delivered only to one user. Not stored in channel history. Used by commands like /giphy.
errorAn error message from a failed command. Ephemeral and only delivered to one user.
replyA message in a reply thread. Messages with a parent_id are automatically this type.
systemA message generated by a system event, such as updating the channel or muting a user.
deletedA soft-deleted message.

Retrieving a Message

Use getMessage to retrieve a single message by its ID:

const message = await client.getMessage(messageID);

// For soft-deleted messages, retrieve the original content (server-side only)
const deletedMessage = await serverClient.getMessage(messageID, {
  show_deleted_message: true,
});

Get Message Options

NameTypeDescriptionDefaultOptional
show_deleted_messagebooleanIf true, returns the original content of a soft-deleted messagefalse

The show_deleted_message option is only available for server-side calls.

Updating a Message

To update a message, call updateMessage with a message object that includes the message ID:

const message = { id: messageId, text: "Updated message text" };
const updated = await client.updateMessage(message);

Partial Update

Use partial updates to modify specific fields without replacing the entire message. This is useful when you want to retain existing custom data:

// Update text
await client.partialUpdateMessage(originalMessage.id, {
  set: { text: "Updated text" },
});

// Remove a custom field
await client.partialUpdateMessage(originalMessage.id, {
  unset: ["color"],
});

// Update nested properties
await client.partialUpdateMessage(originalMessage.id, {
  set: { "details.status": "complete" },
});

Deleting a Message

Messages can be deleted in three ways:

  • Soft delete: The message is marked as deleted but data is preserved. Can be undeleted.
  • Hard delete: The message and all related data (reactions, replies) are permanently removed.
  • Delete for me: The message is marked as deleted only for the current user. Other channel members are not affected.

Deleting a message does not delete its file attachments. See deleting attachments for more information.

// Soft delete
await client.deleteMessage(messageID);

// Hard delete
await client.deleteMessage(messageID, { hardDelete: true });

// Delete for me
await client.deleteMessage(messageID, { deleteForMe: true });

Delete Type Comparison

BehaviorSoft DeleteHard DeleteDelete for Me
Can be done client-side
Message type set to “deleted”-
Data preserved-✓ (for user)
Reactions and replies kept-
Can be undeleted--
Affects other users-
Recoverable--

Delete for me is limited to 100 messages per user per channel. Contact support to increase this limit.

Undeleting a Message

Soft-deleted messages can be restored using a server-side call:

await client.undeleteMessage(messageID, userID);

Messages can be undeleted if:

  • The message was soft-deleted (not hard-deleted)
  • The channel has not been deleted
  • It is not a reply to a deleted message (the parent must be undeleted first)
  • The user performing the undelete is valid