JWT explained: how to decode tokens safely
Learn JSON Web Token structure, common claims, and why decoding is not the same as verification.
2026-06-01 · 6 min read
Guides
Original tutorials and reference articles for developers and automation engineers. Each guide links to related Flashman tools you can use immediately in your browser.
23 guides · also read our blog
JSON formatting and validation: a practical guide
How to pretty-print, minify, and validate JSON for APIs, configs, and logs—without leaking data.
2026-06-01 · 5 min read
Base64 encoding explained (and why it is not encryption)
What Base64 is for, when to use it, and common pitfalls with Unicode and padding.
2026-05-28 · 4 min read
YAML vs JSON: when to use each format
Compare readability, tooling, and trade-offs for configuration and APIs.
2026-05-28 · 5 min read
Cron expressions: schedule jobs with confidence
Understand five-field cron syntax and avoid timezone surprises in production.
2026-05-25 · 5 min read
URL encoding: common mistakes and fixes
Percent-encoding rules for query strings, paths, and plus signs in form data.
2026-05-25 · 4 min read
Why client-side developer tools protect your data
How in-browser processing reduces leak risk for tokens, configs, and customer data.
2026-05-20 · 4 min read
MATLAB & Simulink: JSON workflows for engineers
Bridge JSON configuration and MATLAB matrices or structs for automation and calibration.
2026-05-20 · 6 min read
SHA hashing explained for developers
What SHA-256 and SHA-512 do, when to use them, and what hashing is not.
2026-05-18 · 4 min read
Markdown writing guide: syntax, preview, and export
Learn Markdown basics — headings, lists, code blocks, tables — and how to preview or export to PDF in your browser.
2026-06-02 · 7 min read
Regex testing workflow: match with confidence
How to prototype regular expressions safely before shipping validation logic.
2026-05-18 · 5 min read
QR codes for developers: URLs, Wi-Fi, and vCard
When to use QR codes, what to encode, and how to generate them safely for apps and documentation.
2026-06-03 · 5 min read
Hex, RGB, and contrast: a color guide for UI work
Convert between color formats, check contrast, and avoid common mistakes in design systems.
2026-06-03 · 6 min read
UUIDs and correlation IDs in distributed systems
Generate UUID v4 values, trace requests across services, and avoid ID collisions.
2026-06-04 · 5 min read
Password generators: length, entropy, and storage
Create strong passwords in the browser and learn why generation is only half the problem.
2026-06-04 · 5 min read
Unix timestamps and ISO dates: conversion guide
Convert epoch seconds, milliseconds, and ISO-8601 strings without timezone bugs.
2026-06-05 · 5 min read
Text and JSON diff: compare changes with confidence
Side-by-side diffs for configs, API payloads, and code review prep.
2026-06-05 · 5 min read
XML formatting and minification for configs and APIs
Pretty-print XML, validate structure, and ship readable configs to operations teams.
2026-06-06 · 5 min read
SQL formatting for readable queries and code review
Indent SELECT statements, align JOINs, and share queries your team can maintain.
2026-06-06 · 4 min read
CSS beautify and minify for production bundles
Format messy CSS for debugging and minify for faster page loads.
2026-06-07 · 4 min read
HTML entities: encode text for safe markup
Escape &, <, >, and quotes to prevent XSS and fix broken HTML snippets.
2026-06-07 · 4 min read
camelCase, snake_case, and kebab-case: naming guide
Convert identifiers between conventions for JSON, APIs, CSS, and databases.
2026-06-08 · 4 min read
Binary, octal, decimal, and hex conversion
Convert between number bases for low-level debugging, flags, and hardware docs.
2026-06-08 · 5 min read