Files & attachments

You can attach files to any message — in a channel, a DM, or a thread.

Attaching

Four ways to add files while composing:

• Click the paperclip in the composer.
• Drag and drop files onto the composer.
• Paste an image (a screenshot, or a copied file) into the composer.
• Press ⌘/Ctrl + Shift + A.

Files stage as chips under the composer; they're sent when you send the message, so you can add a few and write a note to go with them — or send them on their own, since a message with files doesn't need any text. You can attach up to 10 files to one message, each up to 10 MB.

Every upload is scanned before it's kept. Programs and installers (.exe, .msi, .dmg, .apk, and the like) are always refused, scripts (.sh, .ps1, .js) are refused by default, and so is anything that trips the virus scanner — you'll see a short message saying why, and nothing is stored. If a scan can't run at all the upload is refused rather than kept unchecked. Which script types are allowed is an operator setting, so your workspace may differ; programs and installers are refused everywhere and can't be switched on.

To share something that's blocked, put it in an archive (.zip, .tar.gz) — the archive isn't unpacked, so what's inside is between you and whoever opens it.

Viewing & downloading

Everyone who can see the message can get its files. Images show an inline preview on the message, with the filename and a Download button underneath. Other files show a chip with the name and size — click it to download.

For safety, downloads always save the file rather than opening it in the browser, so a shared file can never run as a page in chat.

Deleting

Deleting a message also removes the files attached to it. Files inherit the message's privacy: a file in a private channel or DM is reachable only by that room's members.