We got tired of reviewing code we could not run.

Two ex-SREs, one shared pet peeve.

At two different companies, Maya and Dex had each built the same thing: a half-working system for previewing other people's code. Both times it lived in a feature flag, both times it rotted, and both times the answer was the same - “we should productize that someday.”

In 2024 they stopped waiting for someday. Tunnel's prototype was a single script that started a container, waited for health checks, and printed a URL. Two weeks later it had outgrown both their old companies' internal tools.