Sharing Files

With file attachments, you can share additional information that will help your team to visually understand your ideas. Sharing videos, voice recordings, screenshots, and photos will make your messages more effective and clear.

Attach Files to Messages

You can attach files to messages in the following ways:

  • Use the attachment icon - select the paperclip icon inside the message input box
  • Drag and drop
  • Paste from the clipboard

Preview File Attachments

Mattermost has a built-in file previewer that you can use to:

  • Download files
  • Share public links
  • View media

Select the thumbnail of an attached file to open it in the file previewer.

Downloading Files

You can download an attached file by selecting the download icon next to the file thumbnail.

Viewing Media

The following media formats are supported on most browsers:

  • Images: BMP, GIF, JPG, JPEG, PNG, SVG
  • Video: MP4
  • Audio: MP3, M4A
  • Files: PDF, TXT

Other document previews (such as Word, Excel, or PPT) are not yet supported.

Attachment Limits and Sizes

The ability to attach a maximum of 10 files per post is available today for Cloud deployments and will be available for self-hosted deployments in Mattermost Server v5.32 and later.

The default maximum file size is 50 MB, but this can be changed by the System Admin.