API Builder & Tester
Send HTTP requests from your browser — custom headers, bodies, params, saved collections, and one-click cURL/Fetch/Axios snippets. Developers debug a REST endpoint without leaving the tab — runs locally, free to start.
How to Use the API Builder & Tester
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See allAPI Request Builder
Build HTTP requests with method, URL, headers, and body — then generate matching curl commands. Prototype endpoints without leaving the tab — local, free, no signup.
API Tester
Test any HTTP endpoint by sending GET, POST, PUT, or DELETE requests directly from your browser. View response status, headers, and body.
Code to cURL Converter
Convert fetch, XHR, and HTTP client snippets to equivalent curl commands — headers and auth preserved for terminal debugging sessions.
Image to Base64
Encode images to Base64 data URIs for CSS embedding and API payloads. Inline a logo without extra requests — local encoding, free, no signup.
Secure Note Sharer
Share secrets securely via self-decrypting note links — AES ciphertext in the URL fragment, key in the link query. Send passwords without trusting inboxes — local crypto-js AES, free, no signup.
Frequently Asked Questions
How do I debug a failing API call fastest?
Reproduce it here first: set method, URL, headers, and body, then send and read the status plus timing. A 401 means auth headers are wrong, 422 means the body shape is off — fix in the builder, then copy the working cURL snippet into your codebase.
Are my API keys and tokens safe here?
Yes — requests fire from your browser with the Fetch API, so keys, tokens, and bodies never pass through our servers. Collections save to your browser's local storage only. Still, use test keys over production secrets when screen-sharing.
What auth methods are supported?
Anything you can express as custom headers — paste Bearer tokens, Basic credentials, or API keys as header rows and send. A typical debug run: add the Authorization header, hit send, confirm 200, then generate the Axios snippet for your app.
Can I save and organize request collections?
Yes — save requests into named collections in local storage, grouped by project or API, and reload them without retyping. Export the generated cURL per request for teammates; collections themselves stay on your machine.
Are there usage limits on API Builder?
There is no per-use counter: requests fire from your browser, collections live in localStorage, and snippets copy to clipboard — all with no caps. The only gate is the Pro page lock for anonymous visitors: sign in free for full access. No credits or downloads are ever involved.
What guards exist before a request goes out?
Bodies marked JSON must parse or sending stops with an error; requests abort after 20 seconds. The History panel keeps your last 50 calls with method, status, and time.
Related Developer Tools
API Request Builder
Build HTTP requests with method, URL, headers, and body — then generate matching curl commands. Prototype endpoints without leaving the tab — local, free, no signup.
API Tester
Test any HTTP endpoint by sending GET, POST, PUT, or DELETE requests directly from your browser. View response status, headers, and body.
Last updated October 2026