- JSON Tree Visualizer
Explore JSON as a searchable, collapsible tree with paths, details, and statistics.
- Regex Tester & Explainer
Test regular expressions with live match highlighting and a plain-English breakdown of the pattern.
- JSON Formatter & Validator
Validate, pretty-print, and minify JSON with clear error messages. Runs entirely in your browser.
- JWT Decoder
Decode JSON Web Tokens client-side: header, payload, claims explained, and expiry status. Nothing leaves your browser.
- JSON to TypeScript
Paste JSON and generate TypeScript interfaces with nested types and optional keys — entirely in your browser.
- JS Date Formatter
Pick locale and date parts, see live Intl output, and copy snippets for Intl, date-fns, or Temporal.
- JS Equality Explorer
Compare two values with ==, ===, and Object.is — see the coercion steps and classic gotcha presets.
- Number Format Playground
Tweak Intl.NumberFormat options for locale, currency, and notation — live output plus a copy-paste snippet.
- String Case Converter
Convert one string to camelCase, snake_case, kebab-case, and six more cases with copy buttons per row.
- URL Parser & Builder
Paste a URL to see every part labeled — protocol, host, path, query params, hash. Edit any piece and copy the result.
- Encode / Decode
Encode or decode Base64, URL components, and HTML entities in your browser. Unicode-safe Base64 included.
- ID Generator
Generate UUID v4, nanoid, or ULID strings in your browser — with collision-probability math for nanoid.
- Event Loop Visualizer
Step through JavaScript event loop examples: call stack, microtask queue, macrotask queue, and console output.
- tsconfig.json Generator
Answer six questions and get a commented tsconfig.json for TypeScript 5.x — browser, Node, or library setups.
- String Escape / Unescape
Escape and unescape JavaScript strings, JSON strings, hex bytes, and Unicode sequences — with a swap button.
- String Inspector
Why .length lies: UTF-16 units vs code points vs graphemes vs UTF-8 bytes, plus hidden-character detection and clean copy.
- Number Base Converter
Live conversion between binary, octal, decimal, and hex — BigInt-backed, with two’s complement and a nibble explainer.
- Array Method Chooser
Pick a goal, get the right array method with a snippet, mutating badges, gotchas, and a searchable full reference.
- Promise Combinator Chooser
Promise.all vs allSettled vs race vs any — answer three questions, then watch simulated promises settle on a timeline.
- Date Duration Calculator
Diff two dates, add or subtract durations, or count down — with business days and vanilla/date-fns/Temporal snippets.
- Sort Comparator Builder
Build multi-key JS sort comparators visually, preview on your JSON, and copy clean compare functions.
- UUID Inspector
Paste a UUID or ULID: version, variant, embedded timestamps decoded — and why v7 is the DB-friendly choice.
- JWT Generator & Signer
Build and sign HS256 JWTs with Web Crypto, or verify a token against a secret. Secrets never leave your browser.
- JSON to Zod Schema
Paste JSON, get a Zod v4 schema — nested objects, unions, nullable fields, optional email and datetime detection.
- JSON Schema Validator
Validate a JSON document against a JSON Schema in your browser — every error with its path, keyword, and message.
- TypeScript Utility Types Explorer
Partial, Pick, Omit, Record, ReturnType and friends — before/after examples, when to use each, and how they work.
- JSONPath Tester
Test JSONPath expressions against your JSON — wildcards, recursive descent, slices, and filters, with matched paths shown.
- Keyboard Event Codes
Press any key and see event.key, event.code, and modifiers live — with a reference table and copy-ready JS snippets.
- ESLint Flat Config Generator
Answer a few questions, get a commented eslint.config.js for JS or TS, React, Vue, or Astro — plus the exact install command.
- Vite Config Generator
Generate a commented vite.config.ts with path aliases, dev proxy, build options, and Vitest setup for your framework.