Tool
Base64 Encode and Decode
Turn text, files and images into Base64 and back. UTF-8, emoji and URL-safe Base64 are handled correctly, and nothing leaves your browser.
- Base64
- Encoder
- Runs offline
Tools
Small utilities for development and QA, running entirely in your browser. More are on the way.
15 tools
Tool
Cron Expression Explainer
Read any cron expression in plain English and see exactly when it runs next — for Unix cron, GitHub Actions, Kubernetes CronJobs and Quartz.
- Cron
- Date & Time
- Runs offline
Tool
Diff Checker
Compare two texts, files or JSON documents and see exactly what changed, down to the word. Nothing you paste leaves your browser.
- Diff
- Runs offline
- Text
Tool
Hash Generator
Hash text or a file with SHA-256, SHA-512, SHA-1 and MD5, sign it with HMAC, and check a download against its published checksum. Files never leave your computer.
- Hash
- Runs offline
- Security
Tool
HTML Entity Encode and Decode
Escape text so it shows as text inside HTML, and turn entities like & and é back into characters.
- Encoder
- HTML
- Runs offline
Tool
JSON Formatter & Validator
Format, validate, unescape and repair JSON. Big numbers stay exactly as written, and nothing you paste leaves your browser.
- Formatter
- JSON
- Runs offline
Tool
JSON to Pydantic
Paste a JSON response and get Pydantic v2 models, dataclasses or TypedDicts — camelCase keys mapped to snake_case fields, optional fields worked out from your samples.
- Converter
- JSON
- Runs offline
- +1
Tool
JSON to TypeScript
Paste a JSON response and get TypeScript interfaces, type aliases or a Zod schema — nested types named, optional fields worked out from your samples.
- Converter
- JSON
- Runs offline
- +1
Tool
JWT Decoder
Decode a JSON Web Token, see at a glance whether it has expired, and verify its signature. Your token never leaves your browser.
- JWT
- Runs offline
- Security
Tool
Regex Tester
Test regular expressions in JavaScript and Python with the real engines: every match and group highlighted, replacements previewed, and the two flavours compared side by side.
- JavaScript
- Runs offline
- Python
- +1
Tool
Unicode Escape and Unescape
Turn \u00e9-style escapes back into readable text, escape text for JavaScript, JSON, Python or HTML, and see every character's code point.
- Encoder
- Runs offline
- Unicode
Tool
Unix Timestamp Converter
Convert Unix time to a date in any time zone, and a date back to Unix time. Seconds, milliseconds, microseconds or nanoseconds — the unit is detected for you.
- Converter
- Date & Time
- Runs offline
Tool
URL Encode and Decode
Percent-encode text for URLs and query strings, decode it back, and see a URL's parameters as a table.
- Encoder
- Runs offline
- URL
Tool
UUID Generator
Generate UUID v4, time-ordered UUID v7, ULID and Nano ID — one or a thousand at a time — and inspect any UUID to read its version and timestamp.
- Generator
- Runs offline
- UUID
Tool
Code playground
Run Python, JavaScript and TypeScript in your browser. Your code is never sent to us.
- JavaScript
- Runs offline
- Playground
- +2