A Discord message is 2,000 characters and a file through a webhook is 10 MB. Those two numbers decide most failures, and neither can be raised by the person scheduling: the character limit is the same for every webhook, and the file limit is the one of a server that has no boost. Preflight posts through a webhook you create in the channel, which is the only way a scheduler can write to Discord without being a bot in your server.
Text
| Limit | |
|---|---|
| Message content | 2,000 characters |
| Webhook display name | 80 characters |
| Forum post title | 1 to 100 characters |
| Edit after publishing | Allowed; the new text is cut at 2,000 |
| Markdown | Allowed, and counts as characters |
A message over 2,000 is cut by Preflight at 2,000, and the composer says so before it goes. The count is characters, so a long link counts in full.
Files
| Rule | |
|---|---|
| Files per message | Up to 10 |
| One file | Up to 10 MB through a webhook on a server with no boost |
| All files together | Up to 25 MB per message |
| Picture formats | JPEG, PNG, WebP and GIF |
| Alt text | Up to 1,024 characters per file |
| Pictures and video together | Allowed |
Discord shows an attachment as a picture or a video by its file extension, so Preflight sends each file with the right one; a file named with no extension is shown as a download. A picture over the limit gets a smaller copy, up to 4,096 pixels on the long side, and your file is not changed.
Channels and forums
A webhook does not say what kind of channel it writes to. In an ordinary text channel a post is a message. In a forum channel a post can only be a new thread with a title, and Discord refuses a post that has none (its error 220001). Preflight lets you set a thread title; without one, it sends the first line of the post as the title, cut to 100 characters, so the post goes through instead of failing.
Options
| Option | What it does |
|---|---|
| Username | The name the post appears under, up to 80 characters |
| Avatar | A picture URL, which must start with https |
| Silent | The message arrives without a notification |
| Thread title | The title of a new forum post |
What a webhook cannot do
A webhook can write, edit and delete its own messages and nothing else. It cannot read the channel, so there are no views and no replies to fetch, and a deleted webhook answers with an error that Preflight reads as "reconnect this channel". If you delete the webhook in Discord, or the channel it belonged to, every post scheduled to it fails permanently.
Discord next to the others
Two thousand characters is shorter than Instagram's 2,200 and longer than Telegram's 1,024 caption, so one caption often needs a different Discord version. Connecting a webhook is on the Discord integration page, and the walkthrough is how to schedule Discord posts. Every network is on the limits page, and Discord is one channel on any plan, the free one included.
Figures from the Discord webhook documentation as Preflight enforces them, checked 29 October 2026.
Questions people ask
- What is the Discord message character limit?
- 2,000 characters for a message sent through a webhook, the way Preflight posts to Discord.
- How large a file can a Discord webhook send?
- 10 MB per file on a server with no boost, up to 10 files and 25 MB in total per message.
- Can I schedule a post to a Discord forum channel?
- Yes. A forum takes a post as a new thread with a title. Set a thread title, or Preflight uses the first line of the post, cut to 100 characters.
- Does Discord allow alt text on images?
- Yes, up to 1,024 characters per file, which Preflight sends as the attachment's description.
- Why did my Discord posts stop working?
- The webhook was deleted, or the channel it belonged to was. Discord then answers with an error that cannot be retried, and the channel has to be connected again.