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Understand HTTP.
Debug it with confidence.

HTTPClarity is a permanently free, knowledge-first guide to learning how HTTP works, finding precise protocol answers, diagnosing failures, and observing controlled behavior.

Start learningOpen the Lab
Conditional requestRead about 304

Request

GET /guide/caching HTTP/1.1
Host: example.com
If-None-Match: "v42"

Response

HTTP/1.1 304 Not Modified
ETag: "v42"
Cache-Control: max-age=60

The validator matched, so the server sends no body and the cache reuses its stored copy.

Choose the route that matches the job

Learn in sequence, look up an exact detail, investigate a symptom, or prepare for a guided experiment.

  1. LearnFollow concepts from messages and connections through caching, negotiation, and browser behavior.
  2. ReferenceCheck the meaning and constraints of methods, status codes, fields, and directives.
  3. TroubleshootWork from observable evidence toward the responsible browser, server, proxy, or cache layer.
  4. LabUse bounded, deterministic scenarios to see protocol behavior without turning the site into an arbitrary request proxy.

Understand before reaching for a tool

Explanations lead with the direct answer, distinguish protocol rules from common implementation behavior, and point back to primary specifications.

A Lab with deliberate boundaries

Lab scenarios expose only reviewed behaviors with bounded inputs and outputs. HTTPClarity will not fetch arbitrary URLs, retain request histories, or act as a general-purpose API client.