Best Mastodon API for public profile data

What to require of any vendor here

• Ask what it does with a handle that has no instance. `@name` alone identifies nobody on a federated network — the same local name exists on hundreds of servers, belonging to different people. The correct answer is to refuse it; guessing an instance returns a stranger's data silently.
• Ask which server it reads. Any instance that has seen an account holds a cached copy, and those copies lag. A vendor that queries whichever server is convenient is measuring cache freshness, not the account.
• Ask what it puts in the verified field. Mastodon verifies that an account controls a link, not who the person is. A boolean there asserts an identity check the protocol never performs.

Where the number actually lives

We read followers_count from the account's own instance (official API, no key) — the account's own instance. Handle format: **`user@instance`, and the instance is required.** Mastodon is federated: `Gargron` alone identifies nobody, because a different person can hold that name on every server. A handle without an instance is refused with 400 rather than completed with a default server — completing it would return somebody else's profile with `success: true`. The instance must be a public DNS name: IP literals, ports and paths are refused. The handle comes back fully qualified, so the response value is a valid next request.

What you are handing over

The request goes to the account's origin instance, which is the authoritative one, and every instance runs its own version of the software. Keeping that working across thousands of servers is the part you are handing over.

What this does not return

• No handle without an instance. On a federated network @name alone identifies nobody, so a handle with no instance is refused with 400 instead of guessed.
• No numeric id. The id is the ActivityPub uri, because the numeric id is local to one server — the same account has a different one on every instance.
• No verified flag. Mastodon verifies links, not identity, so verified is null rather than reporting a link check as an identity check.

Our endpoints for this platform — 2

• mastodon/profile — Public profile on mastodon, with the exact follower count.
• mastodon/posts — Recent posts from a public profile on mastodon.

Shape, parameters and the errors each one returns are in the endpoint reference, and this platform has its own page with the recorded response.

What the alternatives cost

We do not restate competitor prices here. The vendor pages carry them — 35 of them — each price read on that vendor's own page, with the date we read it. Readings run from 2026-09-05 to 2026-10-03.

A price copied into a second place is a price that will disagree with itself the first time a vendor changes one. Verify on their page before deciding — we are an interested party.