The developer toolbox that never sees your code.
34 free tools for formatting, converting, inspecting and sharing developer data. Every one of them runs entirely in your browser — no account, no upload, no tracking cookie, and nothing you paste is ever transmitted.
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The tools people reach for first, and the one that gets shared the most.
Code Snapshot Turn a code snippet, diff, JSON payload or terminal output into a clean, shareable PNG… JSON Formatter & Validator Format, validate and minify JSON in your browser. Catch syntax errors with the exact line… JSON Diff & Comparator Compare two JSON documents by structure rather than by text. Reports added, removed and… Regex Tester & Explainer Test a regular expression against sample text with every match highlighted, the capture… JWT Decoder & Inspector Decode JSON Web Tokens in your browser and inspect the header, payload, signature and… QR Code Generator Create QR codes for URLs, text, WiFi credentials, vCards and more, with custom colours and…
Why every tool here runs in your browser
A JSON formatter that runs on a server is a formatter that has seen your credentials, your customer records and your internal API responses. These tools use the same JavaScript engine your application would use, inside the page you are already reading. Open your network panel and you will see the page load and nothing else.
Format & Validate
JSON Repair Fix invalid JSON automatically. Recovers from trailing commas, single quotes, unquoted… JSON Schema Validator Validate a JSON document against a JSON Schema and see every violation with its path, the… JSON Formatter & Validator Format, validate and minify JSON in your browser. Catch syntax errors with the exact line… YAML → JSON Converter Convert YAML to JSON instantly in your browser. Handles anchors, multi-line strings, flow… XML Formatter & Minifier Pretty-print or minify XML in your browser. Validates well-formedness, reports the exact… SQL Formatter Format SQL into readable, consistently indented queries. Supports SELECT, JOIN, CTEs… CSV → JSON Converter Convert CSV to JSON in your browser with control over delimiters, quote handling and type… JSON → CSV Converter Convert a JSON array or object into CSV with flattened nested keys, custom delimiters and a… HTML Entity Encoder Encode text to HTML entities or decode entities back to plain text. Handles named entities…
Developer Utilities
cURL Converter Convert a cURL command into fetch, JavaScript, Python requests, Go, PHP, Ruby, Rust or… Case Converter Convert text between camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE… .gitignore Generator Generate a .gitignore file for your stack, with sensible defaults, editor files, OS files… Regex Tester & Explainer Test a regular expression against sample text with every match highlighted, the capture… Cron Expression Builder Build a cron expression from plain English, see the next run times, and get the equivalent… Unix Timestamp Converter Convert Unix timestamps to human-readable dates and back, in seconds, milliseconds… JSON Schema Generator Generate a JSON Schema from a sample document, with inferred types, required fields and… Text Diff Checker Compare two blocks of text line by line and word by word, with additions, deletions and… JSON Diff & Comparator Compare two JSON documents by structure rather than by text. Reports added, removed and… .env Editor & Parser Parse a .env file, mask secret values, spot duplicates and invalid keys, and copy a… UTM Campaign Builder Build campaign URLs with correct UTM parameters, validate them and check whether a link is… HTTP Status Code Reference A complete reference of HTTP status codes: what each one means, when to use it, and how… Markdown Live Preview Write Markdown on the left and see the rendered result on the right, with GitHub-flavoured… WCAG Contrast Checker Check a foreground and background colour pair against WCAG 2.2 AA and AAA contrast… Nano ID Generator Generate Nano ID style identifiers with a custom alphabet and length, using crypto-grade… Find & Replace Tool Find and replace text with plain strings or regular expressions, case sensitivity and… Date Difference Calculator Calculate the exact difference between two dates in days, hours, minutes and seconds, with…
Encode & Hash
Base64 Encoder & Decoder Encode text to Base64 or decode Base64 back to text, with URL-safe output, UTF-8 handling… URL Encoder & Query Parser Percent-encode or decode URLs, and parse a query string into readable key and value pairs… Hash Generator Generate SHA-256, SHA-384 and SHA-512 digests, plus HMAC signatures, directly in your… JWT Decoder & Inspector Decode JSON Web Tokens in your browser and inspect the header, payload, signature and… UUID Generator Generate UUID v4 (random) and UUID v7 (time-ordered) identifiers in bulk, with options for… Checksum Calculator Compute CRC32, Adler-32, Fletcher-16 and CRC-16 checksums of any text in your browser, with…
Guides
Longer explanations for the concepts behind the tools.
How to Read a JSON Web Token (JWT) 6 min read · A practical guide to reading a JSON Web Token: what the header and… Twelve Regular Expressions Worth Knowing by Heart 8 min read · Twelve regular expressions for the tasks that come up in every project… Cron Expressions: A Cheat Sheet and Its Traps 7 min read · The five fields of a Unix cron expression, the day-of-month and… UTC vs Local Time: The Bugs It Causes 6 min read · Why storing local time is a bug waiting to happen, how daylight saving… WCAG Contrast Ratios for Developers 5 min read · What the contrast requirements actually are, which ones apply to your UI… Handling Environment Variables Safely 6 min read · How to keep credentials out of version control and out of your shell…
A tool that earns its place in your workflow
Every tool here does one job, loads instantly and gives you a result you can copy. No dashboard, no onboarding, no paywall halfway through.
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