HTTP Request/Response Workbench

Trace method semantics, headers, status codes, bodies, caching, and timing in one HTTP exchange

Interactive HTTP request/response animation showing request line, headers, body, response status, cache validation, redirect/throttle behavior, and timing phases from DNS through download.

HTTP semantics Headers and body Timing waterfall

HTTP request/response workbench

Follow one exchange from connection setup through request fields, server processing, status code, response headers, and body transfer. Switch scenarios to compare caching, creation, redirects, and rate limits.

GET /api/device/42request line

200 OKresponse status

229 mstotal timing

safe + idempotentmethod semantics

Scenario

Request Controls

Connection profile new HTTPS New HTTPS connection Reused HTTP/1.1 connection HTTP/2 existing connection

Server think time 84 ms

Response body size 2.4 KB

Ready: inspect connection setup

Watch For

HTTP defines message semantics. DNS, TCP, and TLS affect timing, but they are connection setup around the HTTP exchange.

MethodGET is safe; POST is not idempotent; PUT is idempotent but not safe.

StatusThe status line tells the client how to interpret the response.

HeadersMetadata controls media type, caching, authentication, and retries.

TimingConnection reuse can remove DNS, TCP, and TLS setup from later requests.

Exchange Flow

connection setup

1. ResolveDNS/TCP/TLS

2. Requestmethod headers body

3. Processserver checks

4. Responsestatus headers body

5. Reusecache or connection

HTTP Messages

GET /api/device/42 HTTP/1.1Host, Accept, Authorization

HTTP/1.1 200 OKContent-Type, Cache-Control, ETag

Timing Waterfall

Readouts

GETmethod and resource intent

200 OKresponse class and result

response bodypayload direction and size

cacheable with ETagfreshness or validation behavior

new HTTPSconnection profile

229 mstotal request time

Diagnosis

Step Transcript

Quick Reference

RequestRequest line, header fields, and optional content tell the server what action the client wants.

ResponseStatus code, reason phrase, headers, and optional content tell the client what happened.

SemanticsSafe means read-only intent. Idempotent means repeated identical requests have the same intended effect.

How To Read The Animation

The blue token is the request and the orange token is the response. The small edge node represents DNS and connection setup; it is not part of HTTP semantics, but it can dominate timing on constrained IoT links.

A 304 response normally has no representation body; the client reuses a cached representation. A 307 redirect preserves the method, unlike older redirect patterns that some clients historically rewrote.

Technical Accuracy Notes

This workbench follows the HTTP core model in RFC 9110: methods have semantics independent of any specific transport connection, and status codes communicate the result of applying those semantics.

The timing numbers are a teaching model. Real timing depends on DNS cache state, TCP/TLS version, HTTP/2 or HTTP/3 reuse, congestion, server work, payload size, compression, and radio sleep behavior.

Primary references: RFC 9110 HTTP Semantics, RFC 9111 HTTP Caching, and RFC 6585 Additional HTTP Status Codes.