API Design · Senior · Question 38 of 75

How can you roll out a risky API change safely?

1Change it in production and watch Twitter
✓Correct answer: Behind a feature flag or new version, canary to a small share of traffic or selected clients, monitor errors and roll back quickly
3Deploy to all clients at once on Friday

Explanation

Shadow traffic (replaying real requests against the new version) can also catch differences before release.

Further reading

Kubernetes: Liveness, Readiness and Startup Probes ↗

Test yourself

Take the API Design · Senior quiz: questions and options are shuffled, and you get a review of your mistakes at the end.