🧰 Engineering Essentials · Diagnostic Foundations

Debug HTTP APIs methodically

Request-level forensics: headers, status semantics, timing, and auth layers isolated step by step.

foundation~25 minAll Software Engineers

Steps

1Reproduce with curl/httpie outside your app — isolate client vs server
2Read status codes literally: 4xx yours, 5xx theirs, 3xx follow redirects explicitly
3Diff working vs failing requests header-by-header; auth and content-type first
4Trace DNS→TLS→TTFB timings to locate network-layer stalls
5Check response bodies for error envelopes even inside 200s
6Capture evidence (verbose output) before changing anything

Common Pitfalls

▲Postman-vs-curl discrepancies from auto-set headers
▲Proxies/VPNs silently rewriting requests mid-flight

Commands

Install with skills CLI

$ npx skills add aniruddhaadak80/skills --skill diagnostic-foundations-http-api-debugging

Install globally

$ npx skills add aniruddhaadak80/skills --skill diagnostic-foundations-http-api-debugging -g

Tags

#http#debugging#api#engineering-essentials#diagnostic-foundations

Install this skill

$ npx skills add aniruddhaadak80/skills --skill diagnostic-foundations-http-api-debugging -a opencode

SKILL.md

# Debug HTTP APIs methodically

> Request-level forensics: headers, status semantics, timing, and auth layers isolated step by step.

## When to Use This Skill

Request-level forensics: headers, status semantics, timing, and auth layers isolated step by step.

## Steps

1. Reproduce with curl/httpie outside your app — isolate client vs server
2. Read status codes literally: 4xx yours, 5xx theirs, 3xx follow redirects explicitly
3. Diff working vs failing requests header-by-header; auth and content-type first
4. Trace DNS→TLS→TTFB timings to locate network-layer stalls
5. Check response bodies for error envelopes even inside 200s
6. Capture evidence (verbose output) before changing anything

## Common Pitfalls

- Postman-vs-curl discrepancies from auto-set headers
- Proxies/VPNs silently rewriting requests mid-flight

View source on GitHub ↗

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