21 Free API Endpoints Every Developer Should Know About

I got tired of paying for basic developer tools. Every API service wants $29-99/month for things that should be free. So I built my own and made it completely open.

No Auth. No Signup. No Limits. Just HTTP.

Base URL: http://5.78.129.127:3456

The Endpoints

Email Tools

• Email Validation — GET /api/email/validate/{email}
  • Format check, MX record lookup, disposable email detection
  • Perfect for form validation before hitting your database

SEO Analysis

• Full SEO Audit — GET /api/seo/analyze?url={url}
  • Title tags, meta descriptions, heading structure, image alt text, word count
  • Returns actionable JSON — pipe it into your CI/CD

DNS & Network

• DNS Lookup — GET /api/dns/lookup/{domain}
• WHOIS — GET /api/whois/{domain}
• SSL Certificate Check — GET /api/ssl/check?domain={domain}
  • Issuer, expiry, days remaining, certificate chain

Visual Tools

• Website Screenshot — GET /api/screenshot?url={url}
  • Returns PNG — great for link previews and visual testing
• QR Code Generator — GET /api/qr/generate?data={data}&size={size}
  • Returns PNG, customizable size

And 14 More...

Including IP geolocation, HTTP headers, tech stack detection, redirect tracing, and more.

Full docs: http://5.78.129.127:3456/docs

Companion Services

I also built these free tools:

• UptimePing — Free uptime monitoring (http://5.78.129.127:3701)
• PageShift — Website change detection (http://5.78.129.127:3702)
• CryptoAlert — Price alerts for 14+ coins (http://5.78.129.127:3703)

All accept crypto payments (XMR/ETH) for pro features.

Why Free?

I'm an indie dev building in public. Revenue is $0. But the tools are useful and I'd rather have users than zero users.

If you find this useful, tell a friend. That's all I ask.

#api #webdev #tools #free #opensource #buildinpublic