Practical guides for common developer tools
Short, technical articles that explain how these tools work, where they fit in real debugging workflows, and what mistakes to avoid.
Find a guide and tool for your debugging task
cURL works but fetch fails
Keep YAML and JSON value types intact
JSON response has the wrong shape
Inspect JWT claims and expiry
Decode Base64 text
Check regex matches and flags
Inspect SQL joins and filters
Compare timestamp seconds and milliseconds
cURL Works but fetch Fails: Compare CORS, Cookies and JSON
Convert a cURL request to fetch, compare method, headers and body, and separate browser CORS failures from HTTP errors and JSON parsing failures.
YAML to JSON: Preserve Strings, Booleans and Leading Zeros
Convert YAML configuration to JSON without losing string IDs, leading zeros or null values. Test types, duplicate keys and a data-only round trip with a reproducible fixture.
Decode Double-Encoded JSON in an API Response
Identify a JSON object wrapped inside a JSON string, decode it in two steps, and fix the serializer that produced escaped quotes.
HAR Status 0 vs HTTP 500: Find Where an API Request Failed
Use browser network captures to distinguish an absent HTTP response, a CORS failure and a server 500, then correlate the request with logs.
URL Encoding explained
Understand URL encoding, percent escapes, query strings, and how to debug encoded URLs safely.
Regex basics for developers
A practical introduction to regular expressions for validation, extraction, log search, and text debugging.
Common JSON syntax errors and how to fix them
A practical guide to the JSON mistakes developers see most often: trailing commas, single quotes, comments, unescaped characters, and broken nesting.
Debug API JSON Responses: HTML Errors, Empty Bodies and Wrong Types
Debug JSON parsing failures with repeatable examples for HTML error responses, 204 empty bodies, string-versus-object payloads and valid JSON that violates an API contract.
Why formatting SQL queries helps debugging
Learn how SQL formatting makes long queries easier to review, compare, optimize, and explain during backend debugging.
How to prettify application logs for debugging
A practical workflow for cleaning log output, extracting stack traces, formatting JSON logs, and sharing useful debugging notes safely.
How to decode a JWT token
Learn how to decode JWT header and payload claims in the browser, read exp and iat values, and avoid common token mistakes.
How to convert Unix timestamp to date
Convert Unix seconds or milliseconds into readable dates and understand timezone differences in API logs and JWT claims.
How to encode and decode Base64
Understand Base64 encoding, decode strings safely in the browser, and connect decoded output to JSON, JWT, and file workflows.
How to Analyze HAR Files for API Debugging
A practical workflow for reading HAR files, finding slow requests, spotting 4xx/5xx failures, and sharing safe network summaries.
How to Read Java Stacktraces and Find Root Causes
Learn how to identify Caused by chains, application frames, framework noise, and the line of code most likely responsible for a Java failure.
Common JWT Security Mistakes Developers Should Avoid
A developer checklist for JWT algorithms, expiry, issuer, audience, signature verification, token storage, and safe debugging.
How to Detect Breaking Changes in OpenAPI / Swagger Files
A practical review process for comparing OpenAPI specs and identifying endpoint, method, response, and schema changes that can break clients.
SQL Query Debugging Checklist
A checklist for formatting SQL, finding dangerous updates, checking joins, reviewing filters, and preparing safer database debugging sessions.
How to Debug API Logs Using Correlation IDs
Use request IDs, trace IDs, and correlation IDs to connect API failures across logs, HAR files, stacktraces, and service boundaries.
Cron Expression Examples for Developers
Common cron examples for developer jobs, backups, reports, retries, and operational schedules, with cautions about timezone behavior.
JSON Schema Validation Explained
Understand how JSON Schema describes payload shape, required fields, types, arrays, objects, and practical API validation limits.