Mastodon is the one network on this list that can schedule a post by itself: the web app has a "schedule" option and the API has a scheduled_at field. So the first question is whether you need a tool at all.
When Mastodon's own scheduling is enough
If you post to Mastodon only, from one account, a few times a week, use the built-in option and stop reading. It works, it keeps the post on your instance, and it needs no third party.
A tool earns its place when the same post also goes to Bluesky, Threads, LinkedIn and Instagram, when you run more than one account or instance, when you want a queue with fixed slots, when someone else needs to approve the post, or when you want the figures from all networks in one place.
How a tool connects to your instance
Every Mastodon server is its own site, so a tool has to register itself with your instance first and then send you through that instance's authorisation page. You type the instance address (mastodon.social, fosstodon.org, your own), approve the scopes, and come back. The tool stores a token for that instance only. Preflight registers on the fly, so any instance works, including one you run yourself.
Limits differ by instance
This is the part most tools get wrong. The default limits are 500 characters, four attachments, 16 MB per picture and 99 MB per video, but they are instance configuration: many servers allow 1,000 or 5,000 characters, some allow more or larger files. The instance reports its own limits through its API, and a tool that assumes 500 blocks posts your server would take.
Counting is also particular. Mastodon counts graphemes, every link counts as 23 characters regardless of length, and a mention @[email protected] counts only the @user part. A tool that counts raw characters shows the wrong number on any post with a link.
Preflight reads each instance's limits when the account connects and counts the way Mastodon does, so the number next to the box is the number the server will see.
What a post can carry
| Default; your instance may differ | |
|---|---|
| Text | 500 characters, counted as above |
| Attachments | 4 pictures, or 1 video, with alt text each |
| Picture | 16 MB |
| Video | 99 MB |
| Visibility | Public, unlisted, followers only, direct |
| Content warning | A spoiler line; the body is folded behind it |
| Sensitive media | A flag that blurs attachments until tapped |
| Language | Declared per post; affects who sees it in filtered timelines |
| Threads | Reply chains |
| Editing | Yes, after publishing |
| Polls | Yes in the API; most schedulers do not expose them |
Preflight exposes visibility, the content warning, the sensitive flag and the language per post, and lets a thread be written as a chain. Mixing pictures and a video in one post is refused by the server, so it is refused in the composer first.
Comments and figures
Replies are readable and answerable from the inbox; you can favourite a reply as your account. Figures available: favourites, replies and boosts, and daily follower counts. Mastodon has no views counter.
Which schedulers support Mastodon
Preflight, Buffer, Publer, Postiz, Typefully, Mixpost and Hypefury post to Mastodon in 2026. Metricool, Later, PostFast, Post Bridge, SocialPilot and Hootsuite do not; SocialBee offers a reminder rather than a post. Of those that do, check three things: whether any instance can be connected, whether the character count follows your instance's limit, and whether links count as 23.
Questions people ask
- Does Mastodon have a built-in scheduler?
- Yes. The web app can schedule a post and the API has scheduled_at. It covers one account on one instance; cross-posting, queues and approvals need a tool.
- Is the Mastodon character limit 500?
- By default. Each instance sets its own; many allow more. Links count as 23 characters whatever their length, and the domain part of a mention is not counted.
- Can a scheduler connect to a self-hosted Mastodon instance?
- If it registers its app with the instance dynamically, yes. Preflight does; some tools support only a fixed list of instances.