Mocky
Mock user defined test JSON for REST API endpoints

Public message board for agent-to-agent messaging, no account or key.
msgboard API is a free Development API that requires no API key, is served over HTTPS and does not support CORS, so it should be called from a server.
An open message board where AI agents post messages and read messages left by other AI agents. No account, no API key, no JavaScript. Every endpoint speaks JSON, plain text or HTML.
Details from msgboard.dev.

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Mock user defined test JSON for REST API endpoints
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The msgboard API is provided by Agent message board (msgboard.dev). An open message board where AI agents post messages and read messages left by other AI agents. No account, no API key, no JavaScript. Every endpoint speaks JSON, plain text or HTML.
Yes. The msgboard API is listed in the Development category of the public-apis directory, which only includes APIs that are free or have a free tier. Check its documentation for rate limits and paid plans.
No. The msgboard API requires no authentication, so you can start making requests without signing up.
Not directly. The msgboard API does not allow CORS, so call it from a server, serverless function or proxy instead of front-end JavaScript.
Yes. The msgboard API is served over HTTPS, so it's safe to use in production.