HTTP:COLON – A quick HTTP header/directive inspector and reference
Hi HN -- I built HTTP:COLON, a small, open-source web tool for quickly checking a site’s HTTP response headers and learning what they mean as you go. Link: https://httpcolon.dev/ What it does - Enter a URL and fetch its response headers - Groups common headers into handy buckets (cache, content, security) - Includes short docs/tooltips for headers and directives so you can look things up while debugging. I find hovering on highlighted headers quite useful! Supports different HTTP methods (GET/POST/PUT/DELETE) Deep links - You can link directly to a host,…
In plain words
HTTP:COLON is an open-source web tool that inspects HTTP response headers from any URL and explains what they mean. Users enter a domain, select an HTTP method, and see headers organized by category—cache, content, and security—with built-in documentation and tooltips for quick reference while debugging. It supports GET, POST, PUT, and DELETE requests, and allows deep linking directly to specific domains for instant inspection. The tool is designed for developers who need fast answers about HTTP headers without switching between multiple resources.
written from the facts on this page · September 2026
From the sources
In the maker’s words, at launch
Hi HN -- I built HTTP:COLON, a small, open-source web tool for quickly checking a site’s HTTP response headers and learning what they mean as you go. Link: https://httpcolon.dev/ What it does - Enter a URL and fetch its response headers - Groups common headers into handy buckets (cache, content, security) - Includes short docs/tooltips for headers and directives so you can look things up while debugging. I find hovering on highlighted headers quite useful! Supports different HTTP methods (GET/POST/PUT/DELETE) Deep links - You can link directly to a host, e.g. https://httpcolon.dev/www.google.com (or any domain) to jump straight into inspecting it. Why I made it - I kept bouncing between DevTools, MDN, and random blog posts while debugging caching + security headers. I wanted one place that’s quick for “what am I getting back?” and “what does this header/directive do?” It’s in beta, and I’d love feedback on: - Missing features you’d want for day-to-day debugging (export/share formats, comparisons, presets, etc.) Thanks!
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