API Tester
Send HTTP requests and inspect responses
What is API Tester?
API Tester is a free developer utility from Farvixo that lets you send HTTP requests and inspect responses. Your input is processed locally in the browser — nothing is sent to a server, which matters when the payload is a token, a config file or production data. Free, unlimited, no sign-up.
How to use API Tester
Paste your snippet into API Tester. It stays on your device, which matters when you are handling tokens, config or production data.
API Tester processes the input instantly and points at the exact line when something is malformed, so you can fix it rather than hunt for it.
Copy the result to your clipboard or download it. Free, unlimited and no sign-up.
Frequently Asked Questions
Is it safe to use a real API token here?
Yes. Requests are sent directly from your browser to the API — they do not pass through our servers, and nothing is logged. A tool that proxied your request would see your token, which is exactly what this design avoids.
Why do I get a CORS error?
Because the request comes from a browser, and the API you are calling has not allowed this origin. That is the API's policy, not a fault in the tool. Testing such an API needs a server-side client like curl, which is not subject to CORS.
Which methods and body types are supported?
GET, POST, PUT, PATCH, DELETE and HEAD, with custom headers and JSON, form or raw bodies. Response status, headers, timing and body are all shown.
Can I save requests for later?
Requests live in the page only, so closing the tab clears them — a direct consequence of storing nothing on our side. Keep anything you need to reuse in your own notes or a desktop client.
Can I test an API that needs authentication?
Yes — add an Authorization header like any other. Because requests go straight from your browser to the API, your token is never seen by us.
What you can use API Tester for
- Inspecting or reformatting an API payload while debugging
- Decoding a token or encoded value without pasting it into an unknown website
- Generating test data or identifiers during development
- Validating a config file before it is committed or deployed
API Tester at a glance
- Tool
- API Tester — Developer Tools
- Purpose
- Send HTTP requests and inspect responses
- Input
- Text or values you enter directly
- Output
- Processed output you can copy to the clipboard or download
- Processing
- In your browser — files are never uploaded to a server
- Price
- Free, unlimited, no account required
- Limitations
- Bounded by your device's memory and CPU rather than a server quota
Tips for better results
- Because processing is local, it is safe to paste real credentials or production payloads here — nothing is transmitted or logged.
- When parsing fails, the reported line and column point at the first invalid token, which is usually just after the real mistake.
- Bookmark the tool page directly; it loads without an account and works offline once cached.
Common problems and how to fix them
Parsing fails on valid-looking input
Usually a trailing comma, a smart quote pasted from a document, or an unescaped backslash. Check the reported position first.
Output has unexpected whitespace or line endings
The source used CRLF line endings or a non-breaking space. Normalise the input before processing.
Non-English characters come out wrong
The input was not UTF-8. Re-save the source as UTF-8 and paste it again.
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