Devbelt — JSON, JWT, SQL & Regex Toolbox

20 offline developer tools in one popup: JSON/SQL formatter, JWT & Base64 decoder, regex tester, cron explainer, diff & more.

Devbelt puts twenty everyday developer tools in one popup — and keeps every byte you paste on your own machine. Every tool runs locally. Nothing you paste is uploaded, logged or analysed — the JSON formatter, the JWT decoder and the rest all work with your network unplugged. Devbelt asks for a single permission (storage, to remember your settings) and cannot see your tabs, your browsing history or the pages you visit. Paste a production token or a customer payload with a clear conscience. ━━━ FREE FOREVER ━━━ • JSON Formatter — beautify, minify or split to JSON Lines, sort keys, and get the exact line and column of the first error. Trailing commas, // comments, single quotes and Python's True/None are repaired automatically, so a copied log line or a pasted dict just works. • Base64 & Data URI — encode or decode, URL-safe alphabet, padding on or off, data: URIs. Auto mode works out which direction you meant. • URL Encode / Decode — component, whole-URL or form (+ for space) styles, one line at a time if you like. • Case Converter — camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE, dot.case, Title Case, Sentence case, slugs and more, all at once. Click any row to copy it. • Text Cleaner — trim, drop blank lines, collapse whitespace, dedupe, sort (A-Z, by length, natural, shuffle), number lines, add a prefix or suffix, re-join with any separator. ━━━ DEVBELT PRO ━━━ • SQL Formatter — reindent a one-line query, raise the keywords, or squash it all back down. Dialect-agnostic: Postgres, MySQL, SQLite, SQL Server. • Cron Explainer — plain-English description of any crontab or 6-field expression, plus the next runs in your own timezone. • Regex Tester — live match highlighting, capture groups, named groups, and replace with $1 references. • JWT Decoder — header, claims and signature laid out, expiry in human time, HS256/384/512 verification if you paste the secret. The token never leaves your browser. • Timestamp Converter — epoch seconds, milliseconds, microseconds, ISO 8601 or a plain date string, shown in local time and UTC with the week number and a relative reading. • Hash & HMAC — MD5, SHA-1, SHA-256, SHA-384 and SHA-512, hex or Base64, with HMAC when you add a key. • CSV ↔ JSON — either direction, delimiter detection, typed values, and a Markdown table on request. • JSON → Types — TypeScript interfaces, Go structs with json tags, or Python dataclasses, inferred from a sample payload with optional fields detected across array items. • YAML ↔ JSON — convert config either way, including multi-document files and block scalars. • Text Diff — line-by-line comparison of two blocks with a unified diff you can paste into a review. • Escape & Entities — HTML entities plus string escaping for JSON, JavaScript, SQL, the shell, regular expressions and \u sequences. • Colour Converter — HEX, RGB, HSL and OKLCH side by side, WCAG contrast against black and white, and a nine-step tint scale. • Number Base — binary, octal, decimal, hex and base 36, with bit width, two's complement and a byte-size reading. • URL Inspector — every part of a URL, a table of query parameters, nested encoded links spotted for you, and tracking parameters stripped on request. • ID & Mock Data — UUID v4, time-sortable UUID v7, ULID, Nano ID, random hex or Base64, passwords, lorem ipsum and mock JSON rows. ━━━ BUILT FOR KEYBOARDS ━━━ Alt+Shift+D opens Devbelt. Ctrl/⌘+K jumps to the search box; type two letters, press Enter, start pasting. Ctrl/⌘+Shift+C copies the result. Pin the tools you live in so they sit at the top. Dark, light or follow-the-browser themes. "Open in a full tab" gives long payloads room to breathe. ━━━ TRY BEFORE YOU BUY ━━━ Five tools are free forever — no trial, no nag screen, no sign-up. Want the rest? Start a 7-day trial of all twenty with just an email address — no card. Pro is a one-time purchase: pay once, keep it forever, nothing to cancel, and it unlocks on every browser you sign in to. Once you have it, your status is remembered on your device, so the tools keep working offline. ━━━ PRIVACY IN ONE LINE ━━━ The only thing Devbelt ever sends anywhere is "has this person paid?" — never a single character of what you paste.