Developer tools that run in your browser
Runs in your browser · nothing uploaded
DevKit is a small set of utilities for everyday debugging: pretty-print JSON, compare two texts, experiment with regular expressions, and encode values for APIs or URLs. Everything runs locally so pasted payloads stay on your machine.
Use the tools when you need a quick answer without opening an IDE, and read the guides when you want the “why” behind formatting, diffs, and common regex mistakes.
JSON Formatter
Format, minify, and validate JSON instantly.
Diff Checker
Highlight added and removed lines between two texts.
Regex Tester
Debug patterns, flags, matches, and capture groups.
Base64 Encode Decode
Encode and decode Base64 strings in the browser.
URL Encode Decode
Encode and decode URI components safely.
JWT Decode
Inspect JWT header and payload locally — no verification.
Hash Generator
SHA-256 / SHA-384 / SHA-512 hashes via Web Crypto.
UUID Generator
Generate RFC UUID v4 values with crypto.randomUUID().
Guides
Short explainers for formatting JSON safely, reading diffs, and avoiding common regex mistakes — written to sit next to the tools, not replace your IDE.
- How to Pretty-Print and Validate JSON
Why formatted JSON matters for debugging APIs, how minified payloads differ, and how to catch syntax errors early.
- Regex Testing Basics for Developers
A practical intro to testing regular expressions: flags, capture groups, and how to avoid catastrophic patterns.
- JSON Minify vs Pretty Print: When to Use Each
How minified and formatted JSON differ in size and readability, and where each belongs in development and production.
- How to Read a Text Diff (Unified and Side-by-Side)
Understand added and removed lines, hunk headers, and context lines so code and config diffs become useful instead of noisy.
- Common Regex Mistakes (and How to Fix Them)
Greedy quantifiers, unescaped metacharacters, flag mismatches, and other patterns that break in production but look fine in isolation.
- When to Use Base64 (and When Not To)
What Base64 is for, why it is not encryption, and how a browser encoder helps during API and data-URL debugging.
- URL Encoding Basics for Query Strings
Why spaces become %20, when to encodeURIComponent, and how to debug broken redirects without guessing.
Why keep these utilities in the browser?
Opening a full IDE for a one-line encode or a quick JSON format is slow when you are already in a ticket, chat, or docs tab. DevKit keeps those micro-tasks local: paste, transform, copy. There is no account wall and no server round-trip for the tool logic itself.
That matters when payloads include tokens, customer identifiers, or staging secrets you would rather not upload to a random online formatter. Treat every paste as sensitive anyway — Base64 is not encryption — but local processing removes one unnecessary hop.
Use the guides when you want the reasoning behind a workflow, and the tools when you already know what you need and just want the answer fast.