Pablo Fernández Ruiz

Software Developer

I'm a software developer focused on developer tools and data systems. I care about performance, design, and building products that feel solid and intentional, from backend to the final user experience.

I'm currently working on different projects with a range of clients, and I have a keen interest in web scraping.

You can find my code on GitHub, reach me on @pablofdrz, or write me to email. Always open to conversations about engineering and thoughtful product building.

Selected Projects

whatswebA browserless WhatsApp Web SDK for Node.js, built on the native Multi-Device protocol.

microvmRun untrusted code — Go, Python, TypeScript, Rust — in Firecracker microVMs on your own hardware. Written entirely in Go.

WOCWOC (Wake On Call) for Docker apps behind Traefik: idle containers are stopped, and the first request starts them again in about a quarter of a second.

skew-routerSkew protection for self-hosted Next.js on Kubernetes: every open browser tab keeps talking to the build that served it, across deploys and rollbacks.

pixel-mascotProcedural pixel-art mascots for the web, in the style of the old Office assistants: no sprites, every frame computed from distance functions. Eleven characters, 23 gestures and 28 accessories.

Selected Projects

Recent Thoughts

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Catching Spam Campaigns in 64 Bits10/23/2026

A spammer changes one name per copy, and every copy hashes differently. How Mailingest counts near-identical mail with SimHash, four bands and Redis.

SimHashLSHRedisSpamMailingest

The 21st Visitor Broke Live Mail10/22/2026

Buzontemporal's live inbox held one Mailingest stream per visitor, and Mailingest allows 20 per account. Why raising the cap wasn't the fix, and how Centrifugo was.

RealtimeSSECentrifugoNATSMailingest

Building a Temporary Email Service10/22/2026

A temporary inbox takes mail from anyone, for anyone, with no account. How Buzontemporal runs on Mailingest: no attachments, a light path, hard limits.

EmailSecurityRustMailingestSMTP