Developer Tools That Just Work
Format, validate, encode, decode, generate, and transform data with fast browser-based developer utilities. Fast, private developer tools that just work.
Popular Tools
JSON Formatter
Format, beautify, minify, and validate JSON instantly in your browser.
JWT Decoder
Decode JWT headers, payloads, and claims — entirely in your browser.
Base64 Encoder / Decoder
Encode and decode Base64 text with full UTF-8 support.
UUID Generator
Generate cryptographically secure UUID v4 identifiers in bulk.
Regex Tester
Test regular expressions with live matches, groups, and highlighting.
SQL Formatter
Format and beautify SQL queries with configurable indentation.
Categories
Browse tools by what you need to get done.
Data & JSON
Format, validate, and convert structured data like JSON, YAML, and XML.
4 tools
Security & Encoding
Decode JWTs, generate hashes, and encode or decode Base64, URLs, and HTML.
6 tools
Generators
Generate UUIDs, signed JWTs, and cron expressions in seconds.
3 tools
Testing & Development
Test regular expressions and format SQL with professional editors.
2 tools
Date & Time
Convert Unix timestamps and work with dates across formats.
1 tool
All Tools
JSON Formatter
Format, beautify, minify, and validate JSON instantly in your browser.
JSON Validator
Validate JSON syntax and get precise line and column error information.
YAML ↔ JSON Converter
Convert YAML to JSON and JSON to YAML with instant error feedback.
XML Formatter
Format, minify, and validate XML documents with pretty indentation.
JWT Decoder
Decode JWT headers, payloads, and claims — entirely in your browser.
JWT Generator
Create and sign JSON Web Tokens with HS256, HS384, or HS512.
Base64 Encoder / Decoder
Encode and decode Base64 text with full UTF-8 support.
Hash Generator
Generate SHA-1, SHA-256, SHA-384, and SHA-512 hashes with Web Crypto.
URL Encoder / Decoder
Percent-encode and decode URLs and query string components.
HTML Encoder / Decoder
Convert text to HTML entities and decode entities back to text.
UUID Generator
Generate cryptographically secure UUID v4 identifiers in bulk.
Cron Generator
Build cron expressions visually and translate them to plain English.
Regex Tester
Test regular expressions with live matches, groups, and highlighting.
SQL Formatter
Format and beautify SQL queries with configurable indentation.
Unix Timestamp Converter
Convert Unix timestamps to dates and dates to timestamps, live.
Why Developer Toolbox?
Your data should stay yours. Whenever technically possible, everything is processed entirely in your browser.
Fast
Tools load instantly and run at native browser speed. No round trips, no queues, no waiting.
Private
Your data is processed locally in your browser. Payloads, tokens, and queries never touch a server.
Free
Every tool is free to use, with no artificial limits, trials, or feature gates.
No account required
Open a tool and start working. No sign-up, no email, no onboarding.
Frequently Asked Questions
Is my data uploaded when I use these tools?
No. Every tool on Developer Toolbox processes data locally in your browser using JavaScript and native browser APIs. Your JSON, tokens, queries, and text never leave your machine.
Do I need an account?
No. All tools work immediately without registration. Preferences like theme, favorites, and recently used tools are stored only in your browser's local storage.
Are the tools really free?
Yes. All 15 tools are completely free with no usage limits. The site is supported by unobtrusive advertising.
Can I use these tools offline?
Once a tool page has loaded, the processing itself happens locally. A full offline mode (PWA) is on our roadmap.
How do I quickly find a tool?
Press Cmd+K (macOS) or Ctrl+K (Windows/Linux) anywhere on the site to open the command palette, then type the tool name or a keyword like "json" or "jwt".