Mastodon scheduler that follows your server’s limits
PostQuest is a Mastodon scheduler for accounts on any server. You write the post, add images, a GIF, video, or audio, and pick a time. PostQuest reads your server’s own limits, such as its character limit and file sizes, and checks the post against them before it is scheduled.
Mastodon’s web app has no schedule button, even though the Mastodon API supports scheduled posts. PostQuest gives you that scheduling on a calendar shared with Bluesky, Threads, X, and LinkedIn.
- Accounts
- Accounts on any Mastodon server
- Post types
- Text Post, Link Post, Photo Post, Carousel Post, GIF Post, Video Post, Audio Post
- Caption limit
- 500 characters (instance default)
- Depends on the account
- Price
- From $15 a month
- Seven-day free trial, no card required
Last verified
What you can schedule on Mastodon
PostQuest checks every Mastodon post against these limits before it is scheduled. They come from the same rules that power the composer, last checked against Mastodon’s API documentation on September 11, 2026.
| Format | Files | Limits |
|---|---|---|
| Text Post | No media | Caption only |
| Link Post | No media | Caption only |
| Photo Post | 1 file | Up to 16 MB (instance default) · JPEG, PNG, WebP (instance default) |
| Carousel Post | 2–4 files | Up to 16 MB (instance default) · JPEG, PNG, WebP (instance default) |
| GIF Post | 1 file | Up to 16 MB (instance default) · GIF (instance default) |
| Video Post | 1 file | Up to 40 MB (instance default) · MP4, MOV, WebM (instance default) |
| Audio Post | 1 file | Up to 40 MB (instance default) · MP3, OGG, WAV, FLAC, Opus, AAC, M4A, 3GP (instance default) |
Captions can be up to 500 characters (instance default), depending on the account. Hashtags: no hard limit. See every dimension, aspect ratio, and codec on the Mastodon post size and specs page.
Mastodon’s web app vs PostQuest
Mastodon’s API can schedule a post at least 5 minutes ahead, with up to 25 scheduled posts a day and 300 in total, but the official web interface has no option to schedule. Mastodon’s maintainers said in August 2026 that scheduling is in progress alongside a composer rework.
| Feature | Mastodon’s web app | PostQuest |
|---|---|---|
| Price | Free | From $15 a month after a seven-day trial |
| Scheduling | API only; no button in the web app | Any future date and time on a calendar |
| Limits | Set by each server | Read from your server and checked before scheduling |
| Formats | Text, up to 4 images, or one video, audio file, or GIF | Text, link, 1 to 4 images, GIF, video, and audio posts |
| Other networks | Mastodon only | Nine more, including Bluesky, Threads, and X |
| AI assistants | Not part of this comparison | Claude and ChatGPT draft and schedule over MCP, with your approval |
Until Mastodon’s web app ships scheduling, posting at a set time means calling the API yourself or using a scheduler. Use PostQuest if you want Mastodon on a calendar with your other networks and every post checked against your server’s limits.
Which Mastodon accounts can you connect?
Enter your server’s address, sign in there, and approve PostQuest. Limits come from that server, so a server with a 5,000-character limit gets the full length.
- Each Mastodon account counts as one account on your plan, whichever server it lives on.
- You can connect accounts on different servers and post to them together.
- If you revoke PostQuest in your server’s settings, the account shows Reconnect. Failed posts can be retried once it is reconnected.
How to schedule Mastodon posts in PostQuest
Step 1: Connect your Mastodon account
Open Connections, choose Mastodon, enter your server’s address, and approve PostQuest on your server.
Step 2: Write the post
Select the Mastodon account in the composer. The counter uses your server’s character limit, which is 500 on most servers.
Step 3: Add media
Attach up to four images, or one GIF, video, or audio file. PostQuest checks file types and sizes against your server’s settings.
Step 4: Check the requirements
Open Media requirements to see the limits PostQuest read from your server, such as file sizes and image resolution.
Step 5: Choose a time and schedule
Pick a date and time in your workspace time zone and click Schedule. You can change the post until it publishes.
Schedule Mastodon posts from Claude or ChatGPT
Connect PostQuest to Claude or ChatGPT over MCP and ask for posts in plain language. The assistant creates drafts by default; scheduling, publishing, and deleting need your explicit approval.
“Write a Mastodon post about our open-source release with three hashtags and save it as a draft.”
“Post this announcement to Mastodon, Bluesky, and Threads with a version for each, and validate all three.”
“Schedule the approved Mastodon post for Wednesday at 9 a.m. UTC.”
Why a Mastodon post fails, and how to fix it
PostQuest catches these before scheduling, so you fix them in the composer instead of finding a failed post later.
- Text over your server’s limit
- Most Mastodon servers allow 500 characters, and some allow more. Shorten the Mastodon version to the limit PostQuest shows for your server.
- More than four images
- Mastodon posts take up to four images. Pick the strongest four or split them across two posts.
- Images mixed with a video or GIF
- A Mastodon post can have up to four images or a single video, GIF, or audio file, not a mix. Post the video on its own.
- A file over your server’s size limit
- Servers set their own file limits; many allow 16 MB for images and 40 MB for video. Compress the file or post a shorter clip.
- The account needs reconnecting
- If PostQuest’s access was revoked on your server, reconnect the account in Connections, then retry the failed post.
Pricing
Every plan includes all ten networks, the calendar, pre-publish checks, the public API, and the MCP connection for Claude and ChatGPT. Start with a seven-day free trial; no card required.
Solo
$15 / month
or $150 billed yearly
8 connected accounts, 1 workspace
Pro
$29 / month
or $290 billed yearly
20 connected accounts, 3 workspaces
Agency
$69 / month
or $690 billed yearly
60 connected accounts, 15 workspaces
Mastodon scheduler FAQ
Can you schedule posts on Mastodon?
Mastodon’s API supports scheduled posts, but the official web app has no schedule option yet. To schedule without writing code, use a scheduler such as PostQuest, which stores the post and publishes it to your server at the time you choose.
Does PostQuest work with any Mastodon server?
Yes. Enter your server’s address when you connect, sign in there, and approve PostQuest. PostQuest reads that server’s character and media limits, so the checks match your server rather than a fixed default.
What is Mastodon’s character limit?
The default is 500 characters, but each server can set its own. PostQuest shows the limit your server reports in the composer’s character counter.
Is there a free Mastodon scheduler?
Mastodon’s web app can’t schedule, but you can call the API yourself for free. PostQuest has a seven-day free trial but no free plan; it is built for Mastodon alongside other networks.
Can Claude or ChatGPT schedule Mastodon posts?
Yes, through PostQuest’s MCP connection. The assistant can draft Mastodon posts, check them against your server’s limits, and schedule them once you approve.
Keep planning
- Mastodon image and video specs for every format PostQuest publishes.
- Connect Claude to PostQuest to draft posts from a conversation.
Schedule your first Mastodon post
Connect Mastodon, write once, and let PostQuest check the post before it goes on the calendar.