Yappy developer portal

Yappy is a macOS app, but the facts about it are a public API. Releases, docs, FAQ, and pricing are all queryable — no account, no key, no sales call — so an agent answering "what is the current Yappy version" or "will this run offline" reads structured data instead of scraping a marketing page.

The two surfaces

Both read the same data. Pick whichever your client already speaks.

Sixty-second start

# the current release, straight from the same appcast the app's updater reads
curl -s https://yappy.biz/api/v1/releases/latest

# search the documentation
curl -s "https://yappy.biz/api/v1/search?q=accessibility+permission&limit=3"

# the full machine-readable contract
curl -s https://yappy.biz/openapi.json | jq '.paths | keys'

No Authorization header. That is not an oversight — this data is public, and making agents mint a token to read a changelog helps nobody.

Connect the MCP server

{
  "mcpServers": {
    "yappy": { "type": "http", "url": "https://yappy.biz/mcp" }
  }
}

Streamable HTTP transport, seven tools, three resources, no auth. Details on the MCP page.

Guides

• REST API — pagination, versioning, batching, async jobs
• MCP server — tools, resources, annotations, MCP Apps
• Authentication — OAuth 2.1, PKCE, scopes, agent auth
• Errors — the RFC 9457 problem shape and every code
• Rate limits — headers, ceilings, backoff
• Versioning and deprecation — what breaks, and the 180 days of notice
• Sandbox — a test environment that touches nothing real
• API reference — endpoint by endpoint
• OpenAPI 3.1 — generate a client from it

Self-serve credentials

Anonymous access covers reads. If you want a higher rate ceiling or the write scopes, register a client without talking to anyone:

curl -sX POST https://yappy.biz/oauth/register \
  -H 'content-type: application/json' \
  -d '{"client_name":"my-agent","grant_types":["client_credentials"]}'

That is RFC 7591 dynamic client registration. The walkthrough an agent should follow is [/auth.md](https://yappy.biz/auth.md), and the discovery documents are at [/.well-known/oauth-authorization-server](https://yappy.biz/.well-known/oauth-authorization-server) and [/.well-known/oauth-protected-resource](https://yappy.biz/.well-known/oauth-protected-resource).

What this API is not

It does not transcribe audio. Yappy's speech recognition runs on the user's own Mac, on purpose, and there is no hosted endpoint to send a recording to. If your user wants dictation, the answer is to install the app — not to call us.

Stability

/api/v1 is versioned in the path. Breaking changes get a new major version; v1 gets at least 180 days of Deprecation and Sunset headers before it stops answering. Additive fields can appear at any time, so parse leniently. The full versioning and deprecation policy is written down, and GET /api/v1 reports the current status under versioning.