deploymentestablished · medium operational burden

Feature Flag Best Practices

Also known as: feature-toggle-patterns, flag-hygiene, launchdarkly-patterns

Intent

Operational patterns for feature flags: naming, lifecycle, cleanup, testing, avoiding flag debt.

Problem

Flags accumulate: 200 flags, no owners, nested conditionals, untested combinations. Code becomes unmaintainable.

Forces

•Flags enable safe deployment but create technical debt
•Testing 2^N flag combinations impossible
•Cleanup requires process, not good intentions
•Security: client-side flags exposed

Solution

✓ When to Use

•Continuous deployment with feature flags
•Team has >20 flags
•Flag debt causing bugs

✗ When Not to Use

•No feature flags (simple deploys)
•Team not ready for hygiene process

Pros

+Prevents flag debt: cleanup enforced
+Clear ownership: no orphan flags
+Security: server-side default
+Testability: known flag states

Cons

−Process overhead: cleanup PRs, reviews
−Discipline required: easy to skip cleanup
−Tooling needed: expiry alerts, limits
−Nested flags still happen under pressure

Cost Profile

Infrastructure

Low — flag service

Operational

Medium — cleanup process, audits

Cognitive

Low — clear taxonomy

Failure Modes

Flag explosion: 200 flags, 5 cleaned/year
Zombie flags: default ON, no owner, code depends
Nested conditionals: 2^N untested paths
Client-side secret flag exposed in bundle
Expiry missed → flag becomes permanent config

Real-World Examples

Alternatives

branch-based
canary-deployment
dark-launch
config-based

Related Patterns

feature-flag
canary-deployment
dark-launch
kill-switch
experimentation

Competency Domains

deploymentreliability opssecurity complianceeconomics evolutiondistribution communication