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!