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# Notes from real projects: what broke, why, and how it was fixed. Backend, Cloudflare Workers, API security.

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  1. · 4 min read

    Illegal invocation: the Cloudflare Workers bug every test missed

    The contact form answered 502 on staging, the email provider saw no request and all 57 tests were green. The cause was a single line that called fetch as a method, which the Workers runtime rejects and Node does not.

    • Cloudflare Workers
    • TypeScript
    • Debugging
    • Testing

  2. · 5 min read

    A contact form endpoint that assumes hostile input

    Replacing a browser-side email service with a Cloudflare Worker endpoint. Every request goes through size limits, strict validation, a honeypot, rate limiting and server-side Turnstile before a single email is sent.

    • Cloudflare Workers
    • API Security
    • Turnstile
    • TypeScript