API 21

Developer Tools

Only for iPhone

Free · Designed for iPhone. Not verified for macOS.

iPhone

Test APIs from your iPhone. Collections, {{variables}}, pre-request scripts, workflows, and Postman or Apifox import — all stored on device. 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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The developer, Cheuk Hin Wong, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

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    Information

    Seller
    Cheuk Hin Wong
    Size
    41.9 MB
    Category
    Developer Tools
    Compatibility
    Requires iOS 15.1 or later.
    • iPhone
      Requires iOS 15.1 or later.
    • iPod touch
      Requires iOS 15.1 or later.
    • Mac
      Requires macOS 12.0 or later and a Mac with Apple M1 chip or later.
    • Apple Vision
      Requires visionOS 1.0 or later.
    Languages
    English
    Age Rating
    4+
    Copyright
    © 2026 CH.WONG
  • Privacy Policy

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