I Built 121+ Free Browser-Based Dev Tools — Here Are My 10 Favorites

Sylar — Sat, 06 Jun 2026 08:49:32 +0000

Every developer has a set of small utilities they reach for daily — decoding a JWT, formatting JSON, generating UUIDs, testing regex patterns. Most of these tasks don't need a full IDE or installed software.

So I built Filuni — a free, browser-based toolkit with 121+ tools across 12 categories. Here are my 10 favorites for developers:

1. JWT Decoder

Paste a JWT token, instantly see the decoded header and payload. No more copy-pasting to jwt.io.

Try it: filuni.com/filetool/dev/dev-jwt

2. JSON Formatter & Validator

Paste messy JSON, get it beautifully formatted with syntax highlighting. Instantly validates and shows error locations with line numbers.

Try it: filuni.com/filetool/json/json-format

3. UUID Generator

Generate UUID v4 in bulk — 1 to 100 UUIDs at once with one click.

Try it: filuni.com/filetool/dev/dev-uuid

4. Regex Tester

Write regex patterns and test them against sample text with real-time match highlighting.

Try it: filuni.com/filetool/text/text-regex

5. Cron Expression Parser

Enter a cron expression and see a human-readable description plus the next 10 run times.

Try it: filuni.com/filetool/dev/dev-cron

6. JSON Diff

Structurally compare two JSON objects and see added/removed/changed keys highlighted.

Try it: filuni.com/filetool/dev/dev-json-diff

7. cURL to Code Converter

Paste a cURL command and get equivalent code in fetch, axios, or Python requests.

Try it: filuni.com/filetool/dev/dev-curl

8. Code Beautifier

Beautify or minify HTML, CSS, JavaScript, and SQL with one click.

Try it: filuni.com/filetool/dev/dev-beautifier

9. CIDR / Subnet Calculator

Enter a CIDR notation and get network address, broadcast, netmask, and usable host range.

Try it: filuni.com/filetool/dev/dev-cidr

10. Base Converter

Convert numbers between binary, octal, decimal, hex, and any base 2-36.

Try it: filuni.com/filetool/dev/dev-base-convert

Beyond Dev Tools

Filuni also has 100+ tools for:

PDF — merge, split, compress, convert to Word/Excel/Image
Image — compress, resize, crop, QR codes, watermark, EXIF viewer
Video — compress, convert, extract audio, make GIFs
Text — word counter, diff, case converter, Markdown preview
Encryption — AES/RSA encrypt, hash generate, Base64
Color — picker, gradient builder, WCAG contrast checker
Calculators — BMI, loan, compound interest, statistics

Why Browser-Based?

No install — works on any machine, even a Chromebook
Always up-to-date — no version management
Privacy — most tools run 100% client-side
Cross-platform — same tool on Windows, Mac, Linux, mobile

All 121+ tools are free at filuni.com, no signup required.

What dev tools do you use daily? Drop a comment!

DEV Community: Sylar