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Hermeny Santos
Hermeny Santos

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I Built a Free Swiss Army Knife API for Developers — 20+ Tools, One Endpoint

#webdev #api #javascript #opensource

Ever needed a quick QR code, a SHA-256 hash, or a URL slug — and didn't want to install yet another npm package or spin up a whole service?

I built NexTool API — a single API that bundles 20+ developer utilities into one key. It's free, fast (<100ms responses), and runs on Cloudflare Workers.

What's Inside

Tool Endpoint What it does
QR Code POST /qr/generate Generate QR codes as SVG or BMP with custom colors
Meta Scraper GET /meta/extract?url=... Extract Open Graph, Twitter cards, favicon from any URL
Text Analytics POST /text/analyze Word count, readability score, keyword density
Slug Generator POST /text/slug Clean URL slugs from any text
Hashing POST /crypto/hash MD5, SHA-1, SHA-256, SHA-512
Encoding POST /crypto/encode Base64, URL encode/decode
JWT Decode POST /crypto/jwt-decode Decode JWT tokens (great for debugging)
UUID GET /random/uuid Generate UUID v4s
Passwords GET /random/password Secure passwords with configurable rules
Lorem Ipsum GET /random/lorem Generate placeholder text
IP Geolocation GET /ip/lookup Country, city, timezone from IP
Color Convert POST /color/convert HEX ↔ RGB ↔ HSL ↔ CMYK
Contrast Check POST /color/contrast WCAG AA/AAA compliance check
JSON Validate POST /json/validate Check if JSON is valid
JSON Format POST /json/format Pretty-print or minify JSON
JSON Diff POST /json/diff Compare two JSON objects
JSON → CSV POST /json/to-csv Convert JSON arrays to CSV

Quick Examples

Generate a QR code:

curl -X POST https://nextool-api.hermenyjunior7.workers.dev/qr/generate \
  -H 'Content-Type: application/json' \
  -d '{"text":"https://dev.to","format":"svg","size":300}'
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Analyze text readability:

curl -X POST https://nextool-api.hermenyjunior7.workers.dev/text/analyze \
  -H 'Content-Type: application/json' \
  -d '{"text":"Your blog post content here..."}'
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{
  "success": true,
  "data": {
    "words": 5,
    "readingTime": { "minutes": 1, "seconds": 1 },
    "readability": {
      "fleschReadingEase": 86.7,
      "difficulty": "Easy"
    },
    "keywords": [{ "word": "blog", "count": 1, "density": 20 }]
  }
}
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Check color contrast for accessibility:

curl -X POST https://nextool-api.hermenyjunior7.workers.dev/color/contrast \
  -H 'Content-Type: application/json' \
  -d '{"foreground":"#333333","background":"#ffffff"}'
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{
  "success": true,
  "data": {
    "ratio": 12.63,
    "wcag": {
      "aa": { "normal": true, "large": true },
      "aaa": { "normal": true, "large": true }
    }
  }
}
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Why I Built This

I was tired of:

  • Installing 5 different packages for simple utility operations
  • Hitting rate limits on free APIs that only do one thing
  • Managing API keys from 8 different providers

So I bundled everything into one API. One key, one consistent response format, 20+ tools.

Tech Stack

  • Runtime: Cloudflare Workers (TypeScript)
  • Framework: Hono
  • Cost to run: $0 (Cloudflare free tier)
  • Response times: <100ms globally

Try It

The API is live right now:

Hit the root URL to see all available endpoints:

curl https://nextool-api.hermenyjunior7.workers.dev/
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The free tier gives you 1,500 requests/month — enough for personal projects and testing.

Would love to hear what tools you'd want added next. Drop a comment!

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