The dev toolbox.
Always local.
Twelve hand-picked utilities that replace half a tab of online tools. JSON, JWT, regex, hashes, Base64, UUIDs, timestamps. All client-side, all the time.
No payload leaves your browser. Paste production tokens with confidence.If you spend half your day in the network tab and the other half explaining strings to junior devs, this is your shortcut. Every tool here is the same algorithm openssl, jq or jsonlint runs, just without the middleman. Paste, inspect, copy. Do not log into anything.
The dev essentials
12 toolsJSON Formatter and Validator
Pretty-print and validate JSON live as you paste. Spot a missing comma in milliseconds, no upload to a third-party.
Regex Tester (JavaScript Flavor)
Test JavaScript regexes against real input with match highlighting and capture-group breakdown. Catches catastrophic backtracking before you ship it.
JWT Decoder
Decode header and payload of any JWT to inspect claims, scopes and expiry. Signature stays unverified, this is a debug tool not a validator.
Base64 Encoder and Decoder
UTF-8 safe Base64 with URL-safe variant. Useful for inspecting JWT segments, building data URIs, debugging Basic auth.
URL Encoder and Decoder
Component vs full URI mode. Decide whether you want :/?#&= encoded as well or left alone. No more guessing what your endpoint expects.
UUID v4 Generator
Bulk generation of cryptographically random UUID v4 (uses crypto.randomUUID). Handy for seeding test fixtures and migrations.
SHA Hash Generator
Live SHA-1, SHA-256, SHA-384 and SHA-512 via Web Crypto Subtle. The same digests as openssl or sha256sum byte-for-byte.
Unix Timestamp Converter
Drops a Unix timestamp or ISO string and shows seconds, milliseconds, ISO, UTC, local and relative. Auto-detects the input format.
CSV ↔ JSON Converter
Bidirectional CSV ↔ JSON with quoted-field support. The fastest way to inspect a spreadsheet export as an API payload.
HTML Tag Stripper
DOMParser-backed HTML to plain text. Drops scripts, styles and noscript. Use it to extract readable copy from a CMS export.
Text Diff Comparator
Line-level LCS diff between two texts with green / red colour coding. Faster than firing up git for a quick review.
Color Converter (Hex / RGB / HSL)
Hex / rgb / hsl with alpha and live swatch. Round-trip a brand colour through any CSS notation without breaking.
Power workflows
Pretty + minify in one tab
Paste a minified JSON, hit Format, copy. Then switch the action to Minify, copy the compact version. Keep both ready for a PR description.
JWT debug pipeline
Copy the JWT into the decoder, take the iat / exp / nbf numbers from the payload, paste them into Timestamp Converter for human-readable expiry. No backend roundtrip.
CSV to clean data fixture
CSV → JSON, then JSON Formatter to pretty-print, then Find and Replace to scrub PII before committing the fixture.