API Tester & HTTP Client
Test REST APIs and HTTP endpoints with this privacy-first API testing tool. Send GET, POST, PUT, PATCH, DELETE requests with custom headers, authentication, and request bodies. Generate code in 16+ programming languages including JavaScript, Python, PHP, Go, Ruby, and more. Perfect for API development, debugging, and integration testing.
Request Configuration
Response
No response yet
Configure your request and click "Send Request"
Privacy & Features
Privacy First: All requests are proxied through our server. It logs only the target host, HTTP method and your IP address for abuse monitoring; request bodies, header values and responses are not logged or stored. Requests to private or local addresses are blocked and each request times out after 10 seconds.
Request History: Your last 20 requests are saved locally in your browser using localStorage, with credentials (tokens, API keys, passwords) removed. Clear history anytime.
Full HTTP Support: Test any HTTP method (GET, POST, PUT, PATCH, DELETE, HEAD, OPTIONS) with custom headers, query parameters, and request bodies.
About API Tester & HTTP Client
The API Tester & HTTP Client is a comprehensive tool for testing REST APIs and HTTP endpoints directly in your browser. Send requests with any HTTP method, configure custom headers and query parameters, add authentication (Bearer token, API key), and inspect detailed responses including status codes, headers, body content, and performance metrics. Generate code snippets in 16+ programming languages including C#/.NET, Curl/Bash, Dart/Flutter, Go, Java, JavaScript, Kotlin, Node.js, Perl, PHP, PowerShell, Python, R, Ruby, Rust, and Swift. Features an intuitive auto-expanding interface for headers and parameters, multiple body formats (JSON, Plain Text, Raw Text, Form Data), and local request history. Requests are sent through Toolsana's server, which forwards them to the target URL (so browser CORS limits don't apply); the server keeps only minimal abuse-monitoring logs, not your request data.
Why use a API Tester & HTTP Client?
Testing APIs traditionally requires desktop applications or command-line tools like cURL. This browser-based API tester provides a lightweight alternative with code generation for 16 languages. Instantly generate production-ready HTTP request code in 16 programming languages - perfect for documentation, tutorials, or implementing API calls in your projects. View formatted JSON responses, measure response times, inspect headers, and keep a local history of recent requests in your browser (credentials are removed before saving). The auto-expanding interface eliminates manual row management for headers and parameters. Supports GET, POST, PUT, PATCH, DELETE, HEAD and OPTIONS, multiple body formats (JSON, Plain Text, Raw Text, Form Data), and Bearer token or API key authentication. Requests are forwarded by our server, which does not store request bodies, header values or responses.
Who is it for?
Essential for frontend and backend developers testing API endpoints, DevOps engineers debugging microservices, QA testers validating API integrations, and API developers building and documenting REST APIs. Perfect for technical writers creating API documentation with code examples, developers learning new programming languages, teams sharing API integration code across multiple tech stacks, and anyone who needs a quick browser-based HTTP client with built-in code generation for 16 languages.
How to use the tool
Enter your API endpoint URL in the URL field
Select the HTTP method (GET, POST, PUT, PATCH, DELETE, HEAD, OPTIONS)
Add custom headers in the Headers tab - rows expand automatically as you type
Configure query parameters in the Params tab with auto-expanding rows
Add request body in the Body tab (JSON, Plain Text, Raw Text, or Form Data as a URL-encoded string; ignored for GET and HEAD)
Set up authentication in the Auth tab (Bearer token or API key)
Click 'Send Request' to execute the API call
View response status, time, size, headers, and formatted body content
Click 'Generate Code' to create the request in your preferred language
Select from 16 programming languages and switch between them instantly
Copy generated code to implement the API call in your application
Access recent requests from history to replay or modify previous tests
Frequently Asked Questions
How do I test an API endpoint?
Enter the URL, choose the HTTP method (GET, POST, PUT, PATCH, DELETE, HEAD or OPTIONS), and add headers (Content-Type, Authorization), query parameters, a body (JSON, plain text, raw text or URL-encoded form data) and, if needed, a Bearer token or API key, then click Send Request. The tool sends the request through our server (to bypass browser CORS limitations) and displays the response: status code, headers, body and timing. The server blocks private and local addresses and gives up after 10 seconds. Useful for: ad-hoc API debugging, verifying endpoints before writing client code, generating request code in 16 languages.
Is the request sent through a server?
Yes — our backend acts as an HTTP client on your behalf. Reason: browser-based fetch is subject to CORS; many APIs you'd want to test don't return CORS headers for `*` origin. The backend isn't subject to CORS (server-to-server requests don't enforce it). For abuse monitoring, the server logs the target host (not the full URL or query string), the HTTP method, your IP address, whether a body was sent and how many custom headers there were. We don't store request bodies, header values, auth tokens, or response bodies. **Caveat**: if your test request includes secrets (API keys, OAuth tokens, passwords), they transit our backend in cleartext (we use HTTPS, but they're decrypted to forward). For high-security testing, use curl locally.
What's the difference between this and curl?
Functional equivalence; ergonomic difference. **curl**: command-line, scriptable, runs entirely locally (your machine is the HTTP client). **API Tester** (this tool): web UI, no setup, runs through our backend. Use this tool for ad-hoc one-off tests where convenience matters. Use curl when: (1) testing from a script, (2) sensitive credentials (don't transit through a third-party backend), (3) testing private or local addresses (this tool blocks them), (4) testing from a specific network context. Generate curl commands from your test inputs with the 'Curl/Bash' option in Generate Code or the [Curl Command Generator](/tools/curl-command-generator/).
When should I use something other than this tool?
This tool is a lightweight web UI for one-off requests: no collections, environments, automated tests or team sharing. It does not send file uploads (multipart), follow multi-step auth flows, or reach private networks. For long-term API development, complex test suites or team collaboration, a desktop API client or scripted tests in your codebase fit better. Use this tool for: quick debugging, generating request code in 16 languages, no-install scenarios.
How do I send authentication?
Patterns supported. **Bearer token (OAuth/JWT)**: choose 'Bearer Token' in the Auth tab and paste the token; the tool sets `Authorization: Bearer …`. **API key in header**: choose 'API Key' and enter the header name and value, or add a custom header such as `X-API-Key: YOUR_KEY`. **API key in query string**: add it as a query parameter or to the URL like `?api_key=YOUR_KEY`. **Basic auth**: there is no Basic Auth section; add the header `Authorization: Basic <base64 of user:password>` yourself. **Cookies**: add a `Cookie` header. Multi-step auth flows (OAuth redirects) aren't supported by a single-request tester.
Does this support all HTTP methods?
It supports GET, POST, PUT, PATCH, DELETE, HEAD and OPTIONS. Custom or non-standard methods are not available. Bodies are sent for every method except GET and HEAD. Some methods have conventions: GET typically has no body (some servers reject GETs with bodies); HEAD returns headers only (same as GET); OPTIONS is used for CORS preflight. For verifying CORS configuration, use [CORS Header Checker](/tools/cors-header-checker/) — purpose-built for that scenario.
How do I send a JSON body?
Choose the JSON body type and enter a valid JSON string: `{"key": "value"}`; the tool sets `Content-Type: application/json` for you. Verify the JSON syntax with [JSON Formatter](/tools/json-formatter/) before sending — APIs reject malformed JSON. For complex bodies, draft in JSON Formatter, copy here. Multipart file uploads aren't supported. The 'Form Data' body type sends an `application/x-www-form-urlencoded` string that you type in yourself, such as `name=Ada&role=admin`.
Can I save and reuse test requests?
The tool keeps your last 20 requests in your browser's local storage (not on our server) so you can reload and modify them; credentials such as tokens, API keys and passwords are removed before saving, so you need to re-enter them. There are no saved collections. For reproducible testing, generate a curl command (via Generate Code or the [Curl Command Generator](/tools/curl-command-generator/)) and store it in your team's documentation, README, or a shell script. For automated CI testing, write integration tests in your codebase with your test framework.
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