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Free open-source tools for developers. No key or signup.

Every tool on this page is also a free JSON API — a plain GET request with no API key, no account and no tracking. Use them in the browser, from a terminal, or wire them into an AI agent through the MCP server. Repository results are cached for six hours and refreshed in the background, so repeat LOC and star-history calls return quickly.

GitHub/GitLab Star History

Shows star history graph of multiple github and gitlab repositories.

GET /v1/stars
Count LOC online

Online tool for counting lines of code from github/gitlab repositories.

GET /v1/loc
Random Data API

Random integers, shuffled lists and names. No key needed.

GET /v1/random
IP GeoLocation

Free API that retrieves geolocation information from any IPv4, IPv6 or hostname.
JSON and XML are supported
No key or signup needed

GET /v1/geolocation
CORS Proxy

To bypass same-origin policy related to AJAX requests to third party services allowing access to resources from any website.
SSRF-guarded (private IPs blocked, max 5MB).

GET /v1/proxy
HTTP Headers

Inspect the HTTP headers that the server returns when requesting a URL.
Follow redirects included.

GET /v1/headers
Weather API

The API retrieves the actual temperature based on your public IP geolocation or from the city passed as a parameter.

GET /v1/weather
TLS & Cert Checker

TLS version, cipher and certificate expiry for any domain. Catch expired certs before your users do.

GET /v1/tls

Free developer tools and APIs, no key required

These tools cover the things you actually look up during development: how big a codebase really is, how a project's popularity is trending, whether a site's certificate and headers are healthy, and enough geolocation and weather data to build a demo without signing up for anything.

Understand a codebase

Count LOC breaks any public GitHub or GitLab repository down by language, splitting lines of code from blanks and comments and skipping vendor, build and generated directories. Add detail=1 and you also get a per-file list and a breakdown by file extension, which is often more revealing than the language mix. Read the LOC guide for the details.

Track project growth

Star History plots cumulative stars from the repository's creation to today, compares up to six repositories at once, and exports an SVG you can embed in a README with one line of Markdown. See how to add a live chart to your README.

Keep a domain healthy

Use the TLS checker for protocol version, cipher strength and days until a certificate expires, and the HTTP headers checker for HSTS, CSP and the whole redirect chain. The security headers checklist explains what each one actually prevents.

Build demos without signing up

Geolocate an IP with the IP geolocation API, fetch current conditions from the weather API, and generate test data with the random data API — up to 10,000 values per request from the operating system CSPRNG.

Frequently asked questions

Do these tools need an API key?

No. Every endpoint is a plain GET request with no authentication. Add the MCP server at /mcp if you want an AI agent to call them as native tools.

What are the rate limits?

30 requests per minute per IP address, and 300 per minute for the random-data endpoints. LOC and star-history results are cached for six hours; other endpoints should be cached by your application when appropriate.

Is the CORS proxy safe?

It resolves every hostname, rejects private and link-local ranges, and re-validates every redirect hop, so it is protected against SSRF. Still, do not route production traffic or credentials through any third-party proxy.

Can I use these from a script or an app?

Yes. Every tool is a REST endpoint returning JSON, and there is an OpenAPI spec at /openapi.json plus a machine-readable index at /api.json.

Read the guides · API index · OpenAPI spec · llms.txt


Guides & tutorials — how-to articles with runnable code examples

For AI agents & developers

Every tool is a plain GET JSON API — no key, no signup.

MCP server: https://freetools.one/mcp

{
  "mcpServers": {
    "freetools": { "url": "https://freetools.one/mcp" }
  }
}