JSON Studio
Format, validate and minify JSON with precise error locations and a collapsible tree.
Toolkit
79 free tools for developers, students and everyday life. They run entirely in your browser — no sign-up, nothing you type leaves your device, and they keep working offline once loaded.
Small, fast tools for everyday engineering work — formatting, decoding, converting and checking.
For developers: all tools
30 tools shown
JSON → Types
Generate TypeScript interfaces, Zod schemas or JSON Schema from a sample payload.
Data Converter
Convert between JSON, YAML and CSV in either direction.
SQL Formatter
Pretty-print SQL for PostgreSQL, MySQL, SQLite and more.
Diff Checker
Compare two texts line by line or word by word.
JWT Decoder
Decode JWTs, explain the claims, check expiry and verify HMAC signatures locally.
Encode / Decode
Base64, Base64URL, URL, HTML entities, hex and Unicode escapes.
Hash Generator
MD5, SHA-1, SHA-256, SHA-384, SHA-512 and HMAC for text or files.
UUID & ID Generator
Generate UUID v4/v7, ULIDs and nano IDs in bulk; decode the timestamp inside v7 and ULID.
Password Generator
Strong passwords and passphrases from the browser’s secure random source, with entropy.
URL Inspector
Break a URL into parts, edit query parameters as a table and rebuild it.
cURL Converter
Turn a curl command into fetch, axios, Python requests or Go code.
HTTP Status Codes
Every status code with plain-English meaning and when to use it.
Browser & Device Inspector
Viewport, pixel ratio, user agent, time zone, features and your IP as this server sees it.
QR Code Generator
QR codes for links, Wi-Fi and contacts, downloadable as SVG or PNG.
Color Lab
Convert HEX, RGB, HSL and OKLCH, check WCAG contrast and generate tint scales.
Gradient Generator
Build linear, radial and conic CSS gradients visually.
Shadow Generator
Layered CSS box shadows with a live preview.
Fluid Type & Units
Convert px, rem and em, and build clamp() values for fluid typography.
Timestamp Converter
Unix seconds or milliseconds to dates and back, with relative time.
Time Zone Planner
Find overlapping working hours across cities — Dhaka, London and anywhere else.
Cron Explainer
Explain cron expressions in plain English and preview the next runs.
Regex Tester
Test regular expressions with live highlighting, groups and replace preview.
Text Studio
Count words and reading time, convert case and clean up lists.
Markdown Preview
Write GitHub-flavoured Markdown with a live, sanitised preview.
Image Converter
Resize, compress and convert images to WebP, AVIF, JPEG or PNG — metadata stripped.
Git Command Finder
Describe what you want to do and get the right git commands, with warnings.
chmod Calculator
Unix permissions between symbolic and octal notation.
Number Base Converter
Binary, octal, decimal and hex with a bit view and two’s complement.
Prompt Builder
Compose structured LLM prompts with roles, context, examples and output format — with a token estimate.