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I Built 56 Developer Tools With Zero Dependencies — Here's What I Learned

·8 min read
JavaScriptWeb DevProductivityOpen Source

I kept opening random websites for small tasks — formatting JSON, decoding JWTs, converting timestamps, generating UUIDs. Different sites, different UX, most wanting sign-ups or tracking everything.

So I built devprix.dev — 56 developer tools that all run in your browser. Nothing sent to any server. Zero npm dependencies for any tool logic.

The Full Tool List

Formatters & Validators

  • JSON Formatter (beautify, minify, tree view)
  • SQL Formatter (6 SQL dialects)
  • Regex Tester (live highlighting, pattern library)
  • JWT Decoder (header/payload/signature, expiry check)
  • Cron Expression Parser (visual builder, next run times)
  • JSON Path Evaluator & JSON Validator

Generators

  • UUID Generator (v1, v3, v4, v5, v7)
  • Password & Key Generator (RSA, ECDSA, Ed25519 key pairs)
  • QR Code Generator (URL, WiFi, vCard — encoder built from scratch)
  • Test Data Generator (55+ field types)
  • Hash Generator (MD5, SHA-1/256/384/512, HMAC)

Converters

  • Timestamp / Epoch Converter (80+ timezones)
  • Base64 Encoder/Decoder
  • Color Converter (HEX/RGB/HSL, WCAG contrast checker, palettes)
  • YAML <-> JSON (Docker/K8s presets)
  • JSON -> TypeScript (interfaces, Zod schemas)
  • Curl -> Code (Python, JS, Go, Java, PHP, Rust, C#, Ruby)
  • CSV <-> JSON, Markdown <-> HTML, Image -> Base64, and more

DevOps & Config

  • Docker Run -> Compose (and reverse)
  • Chmod Calculator, IP Subnet Calculator
  • Git Command Builder (18 commands with danger warnings)

CSS & Design

  • CSS Gradient Generator (linear/radial/conic, 24 presets)
  • Box Shadow Generator (multi-layer, Tailwind output)
  • Tailwind CSS Lookup (500+ classes, reverse lookup)
  • Favicon Generator

...plus diff checker, JSON diff, slug generator, ASCII art generator, line tools, and more.

The Interesting Technical Bits

QR Code Encoder From Scratch

Instead of using a library, I implemented the full QR encoding pipeline: Reed-Solomon error correction over GF(256), 8 mask pattern evaluation with penalty scoring, and format encoding with BCH codes. 1,161 lines of TypeScript, zero dependencies. Try it here.

Myers Diff Algorithm

The text diff checker uses Eugene Myers' 1986 algorithm — the same one behind git diff. It identifies the shortest edit script and performs character-level highlighting within modified sections. This gives you the precision to see exactly which characters changed, not just which lines. Try it here.

Curl to Code Parser

The curl command parser handles single and double quoted strings, backslash line continuations, multiple header flags, authentication parameters, and generates idiomatic code for nine languages rather than simple string concatenation. Try it here.

Client-Side Cryptography

The password and hash generation tools leverage the Web Crypto API for RSA, ECDSA, and Ed25519 key pair generation, SHA hashing, and HMAC operations. MD5 is implemented from scratch since Web Crypto doesn't support it.

Key Lessons

Zero dependencies is liberating. No supply chain risk, no breaking updates, no bundle bloat. Every algorithm is right there in the codebase. Development takes longer — implementing a QR encoder versus using an npm package — but the outcome is faster, smaller, and fully controlled.

Dark mode is table stakes. The site supports light, dark, and system-preference themes. In 2026, shipping a developer tool without dark mode is leaving users behind.

One tool per page with shared layout scales well. Each tool is its own Next.js route with a shared sidebar and layout. This keeps bundle sizes small (only load the tool you need) and SEO friendly (each tool has its own URL, title, and description).

Client-side is a feature, not a limitation. "Your data never leaves your browser" is a genuine differentiator. Developers paste API keys, passwords, JWTs, and production data into online tools — they should know where that data goes.

Try It

devprix.dev — all free, all private, all in your browser. I'd love to hear which tools are most useful and what to add next.

This is part of DevPrix — 63 free developer tools that run entirely in your browser. No sign-up, no tracking, no server calls.

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