Mastodon
Everything you need to schedule posts on Mastodon: what you can do natively, text limits, image and video sizes, the schedulers that support it, and recent API changes.
Can you schedule natively?
PartlyMastodon's API supports scheduled posts at least 5 minutes ahead (up to 300 per account, 25 per day), but the official web interface has no scheduling control. Use an app or tool that calls the API.
Step-by-step guideText limits
| Field | Limit | How it counts |
|---|---|---|
| post | 500 characters | Every link counts as 23. 500 is the default. Each server can set its own limit. Source |
Image and video sizes
Only what Mastodon documents. "Not stated" means the platform doesn't publish that figure; we don't fill gaps from blogs. Ads specs are marked, because they can differ from normal posts.
-
Image
- Size
- Not stated
- Ratio
- Not stated
- Files
- PNG, JPG, HEIF, WEBP, AVIF
- Limits
- 16 MB max · up to 4 items
Details and sources
Mastodon user docs: up to 4 images per post, up to 16 MB each, downscaled to 8.3 megapixels (enough for 3840 x 2160). Animated GIFs up to 16 MB, one per post, converted to soundless MP4. Limits are per server: clients should read configuration.media_attachments (example mastodon.social values: image_size_limit 16777216 bytes, image_matrix_limit 33177600 px, description_limit 1500) and statuses.max_media_attachments (4).
-
Video
- Size
- Not stated
- Ratio
- Not stated
- Files
- MP4, M4V, MOV, WebM
- Limits
- 99 MB max · up to 1 items
Details and sources
Mastodon user docs: one video per post, up to 99 MB, transcoded to H.264 MP4 at up to 1300 kbps and 120 FPS. No maximum length documented. Example instance config: video_size_limit 103809024 bytes, video_frame_rate_limit 120, video_matrix_limit 8294400 px. Values vary by server.
How tools publish to Mastodon
What each tool's own pages state about Mastodon: 9 auto-publish. A blank cell means the pages do not say.
| Tool | Publishing | Post types | 1st comment | Limits and requirements |
|---|---|---|---|---|
| Buffer | Auto-publish | Daily limit 100 | ||
| CoSchedule | Needs: Choose the account's server when connecting | |||
| Fedica | Auto-publish | textthreadpollboost | Post language code can be set per scheduled post | |
| Jetpack Social | Auto-publish | 100 posts/day suggestion | ||
| Mixpost | post | Needs: Any fediverse instance; free Lite includes Mastodon profiles | ||
| Ocoya | textimagevideothread | 500 per post, 5,000 total; 4 images up to 16 MB; 1 video up to 99 MB | ||
| Postmypost | Daily publication limit 200 | |||
| PostSyncer | thread | |||
| PostyBirb | Needs: Listed among supported sites (also MissKey, Pixelfed) | |||
| Publer | textthreadlinkphoto up to 4videoGIFpollboost | Yes | Text 500 chars, more on some servers; photo caption 1,500; photos and GIFs under 8 MB; video under 99 MB; poll option 50 chars; threads up to 25 posts Needs: Some servers restrict automation | |
| Schedchie | Auto-publish | textimage | Character limit read from the user's server Needs: Works on any instance | |
| SocialBu | textattachmentcontent warningthread (up to 10 replies) | |||
| TimeToPost | Auto-publish | textlink | No media or reply threads; visibility defaults to followers-only Needs: OAuth on your chosen server | |
| TryPost | Auto-publish | |||
| Typefully | Auto-publish | postpollquote postimageGIFvideo | Images 5 MB free and 20 MB paid (JPG, PNG, GIF, WEBP, HEIC, HEIF, AVIF); video WEBM/MP4/M4V/MOV up to 40 MB, max 60 fps Needs: Cross-post an existing draft or create a Mastodon-only draft | |
| Upload-Post | Auto-publish | Needs: Access token credential | ||
| Viraly | Auto-publish | textimagevideocarousel |
Schedulers that publish to Mastodon
23 of the tools we track list Mastodon publishing. Cheapest first.
| Tool | From | Free plan |
|---|---|---|
| Publer | $4 / account / mo | Yes |
| Social Champ | $4 / account / mo | Yes |
| Buffer | $5 / channel / mo | Yes |
| Typefully | $8.25 / mo | Yes |
| TimeToPost | $9.60 / mo | No |
| Zoho Social | $10 / mo | Yes |
| Planly | $10 / mo | No |
| Postpone | $16 / mo | Yes |
| Upload-Post | $16 / mo | Yes |
| TryPost | $19 / mo | No |
| Viraly | $19 / mo | Yes |
| Mixpost | $20.75 / mo | Yes |
| SocialBu | $22 / mo | Yes |
| Postiz | $23 / mo | No |
| PostSyncer | $24 / mo | No |
| Ocoya | $29 / mo | No |
| CoSchedule | $29 / mo | Yes |
| FS Poster | Not published | No |
| PostyBirb | Not published | Yes |
| Jetpack Social | Not published | Yes |
| Schedchie | Not published | No |
| Fedica | Not published | No |
| Postmypost | Not published | No |