Not all launches should be visible. One of the most powerful tools in my backend toolbox is the dark launch — shipping code without exposing it to users.
In one project, we wanted to roll out a new scoring algorithm behind the scenes. Here’s the approach:
- Ship the logic to production behind a feature flag
- Run both old and new code paths in parallel
- Collect metrics and output differences
- Validate real-world impact before enabling it
Tools used:
Unleash, custom logging hooks, and Grafana dashboards for monitoring divergence.This method gave us confidence without panic. No failed deploy rollbacks, just quiet data gathering until we were sure.