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About
API21 is a local API client for iPhone. Build a request, hit Send, and inspect the response — without a laptop, and without an account.
Collections, folders, and tabs keep your APIs organized. Environments swap {{variables}} across URL, params, headers, body, and auth. Pre-request and post-response scripts can set headers and save values back into the active environment. Workflows chain saved requests and run them top to bottom.
Import a Postman collection, a Postman environment, an Apifox project, or an API21 export. Export your workspace as JSON when you want it on another device. Everything stays on this phone.
REQUESTS • Methods, URL, query params, and headers • Body: JSON, XML, text, form-data, x-www-form-urlencoded, GraphQL, msgpack, and binary • Auth: Bearer, Basic, API Key, OAuth 2.0, and Digest • Open several requests in tabs
RESPONSE • Status, time, and size • Pretty, Raw, and Headers • Find inside the response body
WORKSPACE • Collections and folders • Environments with {{variable}} interpolation • Pre-request and post-response scripts • Workflows that run saved requests in order • Search by name, URL, or method • Send history
YOUR DATA • Stored on device • Import Postman, Apifox, or API21 JSON • Export environments, APIs, or the full workspace
Built for people who already live in request editors and want the same workflow in their pocket.
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What's New in API 21
1.0
September 30, 2026



