Notes on feature flags, releases, and engineering from the Featureflip team.
Progressive delivery is two ideas, not one: release progression and progressive delegation. Here's how feature flags turn a deploy into a dial you can turn up slowly.
Eight feature flag best practices for production teams — lifecycle tagging, flat decisions, both-state testing, progressive rollouts, governance, observability, and cleanup discipline.
Featureflip now supports first-class prerequisite flags — a child flag stays off until its parent serves the right variation, no application-side gating required.
Nine feature flag anti-patterns behind real outages — Knight Capital's $460M loss, Slack's day-long cascade, Google Cloud's June 2025 crash. Each with a fix.
73% of feature flags are never removed — one reused bit cost Knight Capital $460M. The four-step playbook to clean up flag debt safely.
Env vars configure where the process runs; flags decide what each request sees. Decision rule, comparison table, and 4 production gotchas inside.