Free Developer Tools
JSON, regex, hashes, UTMs, cron — free developer utilities that respect your clipboard.
Debugging at 2am should not require signing up for a SaaS product. These free developer tools cover the daily grind: pretty-print and validate JSON, test regex with live highlighting, decode JWTs, convert timestamps, and translate cron expressions into plain English. Frontend work gets gradient and box-shadow generators with copy-paste CSS, plus meta tag and robots.txt builders for launch day.
Speed matters most in the tools you reach for dozens of times a day. A JSON formatter that validates as you paste, a regex tester that highlights matches live, a timestamp converter with a ‘now’ button — each one saves seconds, and seconds compound across a career. These utilities are deliberately boring in the best way: no accounts, no API keys, no telemetry phoning home with your proprietary payloads. Because everything executes locally, you can safely paste production tokens, customer data samples, and internal URLs without a second thought — a guarantee no server-side tool can honestly make. Bookmark the ones you use weekly; they load instantly and work the same everywhere.
Popular developers tools
- JSON Formatter — pretty-print, minify, and validate with clear errors
- Regex Tester — live match highlighting and group capture
- UTM Builder — tag campaign URLs with UTM parameters
- Hash Generator — MD5, SHA-1, SHA-256, SHA-512 instantly
- Timestamp Converter — Unix timestamps to dates and back
- Cron Explainer — cron expressions in plain English
Everything runs client-side — your tokens, keys, and payloads never touch a server, which is exactly how dev tools should behave.
Developers — all tools
JSON Formatter
Pretty-print, minify, and validate JSON with clear error messages.
Base64 Encoder
Encode text to Base64 or decode it back — handles Unicode correctly.
Lorem Ipsum Generator
Generate placeholder paragraphs or exact word counts for mockups.
Meta Tag Generator
SEO, Open Graph, and Twitter Card tags in one paste-ready block.
Robots.txt Generator
Build valid crawler rules with sitemap — copy or download.
UTM Builder
Tag campaign URLs with UTM parameters.
CSS Gradient Generator
Design gradients with live preview and copy-paste CSS.
Box Shadow Generator
Fine-tune box shadows with sliders and live preview.
JSON to CSV Converter
Convert JSON to CSV and back — paste, convert, download.
Timestamp Converter
Convert Unix timestamps to dates and back, with a live 'now' button.
Regex Tester
Test regular expressions live with match highlighting and group capture.
Markdown Previewer
Write Markdown and see the rendered preview instantly.
Hash Generator
MD5, SHA-1, SHA-256, and SHA-512 hashes instantly.
URL Encoder
Percent-encode URLs or decode them back.
JWT Decoder
Inspect any JSON Web Token's header and payload.
CSS Minifier
Shrink stylesheets and see exactly how many bytes you saved.
Cron Explainer
Paste any cron expression, get a plain-English schedule.
HTML Entity Encoder
Encode text to HTML entities or decode them back.
UUID Generator
Generate v4 UUIDs in bulk and copy them all at once.
Number Base Converter
Decimal, binary, hex, and octal — all converted live.
XML Formatter
Pretty-print and validate XML with clear error messages.
Color Contrast Checker
Check WCAG contrast ratios for text readability.
Frequently asked questions
Is my code or data sent to a server?
No. Every developer tool runs entirely in your browser with no API calls. Tokens, API keys, and payloads you paste never leave your device.
What JSON operations are supported?
The JSON formatter pretty-prints, minifies, and validates with clear error messages, and the JSON to CSV converter moves data both directions — paste, convert, download.
Are the random generators cryptographically secure?
Yes. The password, passphrase, and UUID generators use the Web Crypto API (crypto.getRandomValues), suitable for real secrets — not Math.random().
Do these tools work for professional use?
Absolutely. They are built to the same standards as paid utilities: correct Unicode handling in the Base64 encoder, proper JWT parsing, and accurate hash algorithms.