Intercom's limit on individual attachments is 100MB for uploads through the Messenger, with currently no cap on how many you can upload. Incoming emails are limited to 20MB including attachments, and anything larger is rejected. Emails you send with attached files have a 20MB limit too, counted across all the files together.
The limit depends on the channel
A customer sends a screen recording in chat and it arrives fine. The same customer emails it and it bounces. That's not a glitch: Intercom sets different limits for the Messenger and for email. Here's the full set, as of Nov 2026.
| Item | Limit | Applies to |
|---|---|---|
| Individual attachment via Messenger | 100MB | Uploads in the Messenger |
| Number of attachments | No limit currently | Messenger uploads |
| Files sent at once in the Messenger | Up to 10 | One send |
| Incoming email including attachments | 20MB; larger is rejected | Email to Intercom |
| Outgoing email with attached files | 20MB total across all files | Your own outgoing emails |
| Messenger attachment link life | 30 minutes | Messenger and chat uploads |
| Email attachment link life | Around 6 months | Email attachments |
Five times the room in chat as in email
The Intercom Help Center sets the Messenger limit at 100MB per file and the email limit at 20MB for the whole message, attachments included. The email limit is on the total, not per file, so three 8MB PDFs in one email won't go through even though each one is small. If a customer needs to send something big, point them to the Messenger.
For your own outgoing emails, the same 20MB total applies. If you need to share a large file, send a link to it instead of attaching it.
Which files get through
By default, customers can send attachments, including images, through the Messenger, email, the API and Facebook. PDFs, images, videos and text files are supported out of the box.
If you can't open a file, its type may not be allowed. You can allow that file type under Settings, Workspace, Security, General, Receiving attachments, and the change applies only to future emails, not ones already received. Executable files such as exe, bat and msi are unsupported, and no workspace can allow them.
Every uploaded attachment is scanned for viruses. If one's detected, the file is quarantined and can't be accessed, which is why a customer's file sometimes appears but won't open.
Links that expire, files that don't
Attachment links behave differently by channel. Messenger and chat uploads now get links that expire after 30 minutes, while email attachments use a longer-lived signed link that lasts around 6 months. The expiry only affects the link. The file itself isn't deleted, and Intercom keeps stored attachments indefinitely by default. Linked attachments aren't indexed by search engines by default either.
That short Messenger expiry matters if you copy attachment links into another system, such as a bug tracker. After half an hour the link stops working, so download the file and attach it there instead of pasting the URL.
Sending files in the Messenger
- Attach and send up to 10 images or files at once.
- Attachments start uploading the moment you insert them, so wait for the upload to finish before you hit send on a big file.
- A gallery shows every photo, video and file in a conversation, which saves scrolling to find the one you need.
How Jira handles file sizes
Jira has a default attachment size of 1 GB per file and a maximum of 2 GB per file, set by an admin. That's useful to know if your support team passes customer files on to developers. If you're comparing support tools more widely, my guide to the best help desk software for small businesses is a good start.
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My advice for teams handling customer files
Tell customers to send large files through the Messenger, not email, and keep your own outgoing emails well under 20MB in total. If you move files into other tools, download them rather than copying the 30-minute link. And if a file won't open, check whether its type needs allowing before assuming it's broken. For a look at other options, my roundups of Intercom alternatives and Help Scout alternatives cover the field.
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Frequently asked questions
What is the Intercom attachment size limit?
100MB per individual attachment in the Messenger.
What is the email limit?
20MB for an incoming email, including its attachments.
Is there a limit on the number of attachments?
Intercom says there's currently none for Messenger uploads.
Why can't I open a file?
Its type may be blocked, so allow it in the security settings. If it's an executable type, it can't be allowed.
Do attachment links expire?
Messenger links expire after 30 minutes, and email links last around 6 months.
