Day 40 of 60
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Production & continuous
Feature flags & canary deploys
Big-bang deploys force you to choose between forward and revert. Flags give you a kill switch on every release; and a way to ship dark to one customer before the world.
ProblemBig-bang deploys; the only rollback is git revert.
How it works
New code ships dark; turn on for 1% → 10% → 50% → 100%. Watch metrics at each step. Kill switch for instant rollback.
What it catches
Reduces blast radius of any deploy. Combined with A/B testing, doubles as a product-research tool.
Tools
Unleash · OSS OpenFeature · OSS Argo Rollouts · OSS Flagger · OSS LaunchDarkly · SaaS Statsig · SaaS
Verdict by project size
Small
Opt
Medium
Rec
Large
Must
Extra-large
Must
Cost
| Project size | Setup | Maint / mo | Tool / mo | CI / run |
|---|---|---|---|---|
| Small <10k LOC | 1d | 1h | $0 | , |
| Medium 10–100k LOC | 3d | 5h | $300 | , |
| Large 100k–1M LOC | 10d | 25h | $3k | , |
| Extra-large >1M LOC | 30d | 80h | $25k | , |
Setup = engineer-days to first useful run ·
Maint = engineer-hours / month at steady state ·
Tool = out-of-pocket $ / month ·
CI = minutes added (or saved) per pipeline run
Lifecycle & ownership
When in lifecycle
Release Operate Observe
Continuous in prod · Always-on, observing real traffic.
Who owns it
SRE / DevOps / Platform
CI/CD, observability, reliability
Collaborates with: Developer
Reference implementations
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OpenFeature playground
Vendor-neutral feature-flag examples using the OpenFeature SDK model.
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flagd
OpenFeature-compatible feature flag daemon with local and remote sync examples.
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Unleash examples
Open-source feature flag examples across SDKs and rollout patterns.
Quick check
Feature flags + canary deploys reduce what specifically?
One question. Pick the best answer. Your streak is saved locally on this device.
Save the lesson
Download SVG ↓
Screenshot for a 1:1, drop it in Slack, or download the SVG.