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Damon
Damon

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I Built 48 Free Online Tools That Never Touch a Server

#webdev #javascript #opensource #showdev

I've been building a collection of free browser-based tools across 4 sites. Every tool processes data entirely in your browser using JavaScript — nothing is ever uploaded to a server.

Why Browser-Only?

  1. Privacy — Your data never leaves your device
  2. Speed — No network latency, instant results
  3. Reliability — Works offline after first load
  4. Trust — Open source, verify the code yourself

The Tools

ToolBox Online — 18 Tools

General-purpose tools for developers and everyone:

  • Code Tools: JSON Escape/Unescape, GraphQL Formatter, TOML Formatter, Lua Beautifier, HTML to JSX
  • Converters: Text to CSV, Pantone to Hex, IP to Hex, Hex to IP, Base64 Encode/Decode, JSON to YAML
  • Calculators: Playback Speed, Geometric Progression, Combination Sum
  • Generators: Random IP, Palindrome, UUID

DevToolKit — 10 Tools

Developer-focused utilities with higher complexity:

  • TOML ↔ YAML conversion, SVG to JSX, SQL to MongoDB
  • Cron Expression Generator, ENV File Generator, Nginx Config Generator
  • Chmod Calculator, HMAC Generator, JSON to Zod

CalcHub — 10 Calculators

Practical calculators for real-world problems:

  • LLM API Cost Calculator (compare GPT-4, Claude, Gemini pricing)
  • TikTok Shop Fee Calculator, Marketplace Fee Calculator
  • Freelance Tax Calculator, Salary Inflation Calculator
  • EV Charging Cost, 3D Printing Cost, Electricity Cost

ImageToolKit — 10 Tools

Image processing without uploads:

  • Resize, Compress, Crop, Circle Crop
  • PNG ↔ JPG, HEIC to JPG conversion
  • Watermark, Image to Base64, Color Palette Extractor

Tech Stack

All 4 sites share the same architecture:

  • Next.js 16 (App Router) + React 19
  • TypeScript + Tailwind CSS 4
  • Deployed on Vercel (free tier)
  • SEO-optimized with JSON-LD structured data

What I Learned

  1. Long-tail keywords work — Tools targeting specific queries like "pantone to hex converter" rank faster than generic terms
  2. Client-side processing is a feature — Users genuinely care about privacy
  3. SEO for tool sites is different — FAQ sections, how-to-use guides, and structured data matter more than backlinks

Open Source

All 4 projects are open source:

Which tool would you use the most? What's missing from the collection? I'm actively adding new tools based on demand.

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