How I released a feature to 200M users

…without any errors 🤯

I turned on a new service that went from 0 ➡️ 350 req/sec immediately.

With zero errors.

“Something must be wrong…” 😅 Working right the first time is uncommon at best, and often means I missed something.

But it really happened! Here’s the story.

Medium gets about 8,000 req/sec to its images endpoint. Most of these requests are handled by Cloudflare’s cache (thank you, Cloudflare!).