Nesake API Tester
Nesake API Tester is a browser-based tool for building and sending HTTP requests to REST APIs and reading back the response — status code, headers, timing, and body — without installing anything or creating an account. It covers the everyday jobs of API work: constructing a request with query parameters, headers, and authentication, sending it, and making sense of what comes back, whether that's formatted JSON, plain text, or an error.
What is an API Tester?
Most modern applications talk to each other over HTTP using REST APIs: one program sends a request to a URL with a method (GET, POST, and so on), optional headers and a body, and the server sends back a response with a status code and usually a JSON payload. An API tester lets you construct that request by hand — instead of writing code just to check whether an endpoint works, what shape its response takes, or whether your authentication header is correct — and inspect the result directly.
Supported HTTP Methods
Retrieve a resource without changing anything on the server.
Create a new resource or trigger an action, usually with a body.
Replace a resource entirely with the data you send.
Apply a partial update to an existing resource.
Remove a resource identified by the URL.
Like GET, but returns only headers, no body.
Ask the server which methods and headers a URL supports.
Authentication
The Auth tab supports the three schemes most APIs use day to day. Bearer Token sends your token in an Authorization: Bearer <token> header, the pattern used by most modern OAuth-style and JWT-based APIs. Basic Auth combines a username and password into a UTF-8-safe base64-encoded Authorization header, still common on internal and legacy services. API Key auth sends a key either as a custom header or a properly encoded query parameter, matching how most SaaS APIs authenticate developer requests. All three accept {{variables}} resolved from your active environment, so a token never has to be pasted in plain text into a saved request.
Useful API Testing Features
Beyond sending requests, the tool includes JSON formatting and validation, cURL import and generation, code generation into several languages, local request history with full request replay, collections with import/export for organizing saved requests, and environments for switching between values like a dev and production base_url without editing the request itself.
Example
Click "Ping (GET)" above the request builder, or send this request yourself, to see a real round trip:
Request
GET https://httpbin.org/get?source=nesake-api-tester Accept: application/json
Response — 200 OK
{
"args": {
"source": "nesake-api-tester"
},
"headers": {
"Accept": "application/json",
"Host": "httpbin.org"
},
"origin": "203.0.113.42",
"url": "https://httpbin.org/get?source=nesake-api-tester"
}
httpbin.org is a public testing service that echoes back exactly what it received — the query string, headers, and requester IP — so it's a reliable way to confirm the tool is sending what you think it's sending before you point it at a real API. The response above is representative; your own IP address and request headers will differ.
Sample requests to get started
If you're new to the tool, the buttons above the request bar load ready-to-send examples so you don't have to build one from scratch to see how it works. Five are REST examples; two appear when you switch to SOAP mode:
Ping (GET)
A plain GET request to a public echo service — the fastest way to confirm requests are actually leaving your browser.
POST Example
Sends a small JSON body to httpbin.org and shows it reflected back in the response.
JSON Example
Fetches a real user record so you can see JSON pretty-printing and collapsing in action.
Bearer Auth Example
Demonstrates the Authorization header being attached automatically from the Auth tab.
Query Parameters Example
Shows params entered in the Params tab being assembled into the URL's query string.
SOAP Example (Calculator)
Switches to SOAP mode and loads a real SOAP 1.1 request against the well-known public "Calculator" demo service (Add operation) — endpoint, SOAPAction, and envelope all pre-filled.
SOAP + WS-Security Example
Same demo service (Multiply operation), with the WS-Security UsernameToken option turned on so you can see it merged into the envelope's Header in the Body (Envelope) tab's preview. The Calculator service doesn't actually check these credentials — it's here to show the header being built correctly, not to demonstrate authentication.
These examples depend on third-party public APIs (httpbin.org, jsonplaceholder.typicode.com) staying available — the tool itself doesn't depend on them, and you can build and send any request manually. The SOAP examples specifically point at http://www.dneonline.com/calculator.asmx, a long-standing public demo service that is plain HTTP (not HTTPS) and, like most legacy SOAP/ASMX services, may not send CORS headers — if this page is itself loaded over HTTPS, or the service doesn't allow cross-origin requests, sending the example may fail even though the request is built correctly. That's a property of the demo service, not a bug in the tool; you can still inspect and edit everything it built.
Browser CORS Limitations
A page running in your browser can only call an API directly if that API's server explicitly allows cross-origin requests via CORS headers. This is a browser security restriction, not a Nesake limitation, and it applies to every browser-based API tool, not just this one. If a request fails, Nesake API Tester reports it as a browser request failure that may be caused by CORS, network connectivity, DNS, TLS, or the target server — rather than assuming it's definitely CORS — since a generic failed fetch can't be distinguished from the browser's error message alone. No server-side proxy is deployed for this tool at present; this page is built so one could be added later without changing how you use it.