Canary Releases
Canary releases are the deployment strategy that lets you ship to 1% of users and know whether it's safe before the other 99% see it. When done right, a bad deploy affects a tiny slice of traffic and rolls back in minutes. When done wrong, you find out
Testing
The most realistic test environment is production. Staging environments, no matter how carefully maintained, diverge from production over time.
Deployment Testing
Feature flags (also called feature toggles or feature switches) are one of the most powerful tools in a modern engineering team's toolkit.
Testing
Gradual rollouts and canary deployments reduce risk but introduce new testing problems: how do you test that the rollout percentage is correct, that monitoring detects regressions, and that rollback works before you need it in production? This guide covers testing strategies for the full progressive delivery lifecycle. What Makes Progressive
Testing
Flagsmith supports local evaluation mode where flag rules are downloaded once and evaluated in-process. This makes it ideal for testing—no HTTP calls during test runs. This guide covers testing flag evaluation, targeting rules, percentage rollouts, and identity overrides in Jest without a running Flagsmith instance. Why Flagsmith Is
Testing
LaunchDarkly is the enterprise standard with the most complete SDK ecosystem. Statsig combines feature flags with built-in A/B experimentation and product analytics. Unleash is the open-source option you self-host. This comparison covers SDK quality, testing support, pricing model, and the tradeoffs for teams of different sizes.
Testing
A/B testing infrastructure is code, and code needs tests. This guide covers testing the experiment layer itself: variant assignment consistency, statistical significance calculations, minimum detectable effect, sample size requirements, and percentage rollout correctness—not just whether the feature exists behind the flag. Testing the Test Infrastructure Most teams write