Feature Flags and Continuous Delivery: Ship It Like You Mean It

Continuous delivery means shipping code to production frequently — ideally on every merge to main. Feature flags are what make that possible without turning every deployment into a high-stakes gamble.

The Core Problem: Deployment vs. Release

There's an important distinction that many teams blur:

Deploying code and releasing features are not the same thing.

Deployment means putting code on a server. Release means making a feature visible to users. In a traditional workflow, these happen together. You deploy, and the feature immediately goes live. With feature flags, you can separate them. That's the foundation of continuous delivery:

Deploy constantly. Release deliberately.

The feature flag controls when code goes from deployed to released. As Scott Hanselman puts it, feature flags let you separate deployment from release, giving you the power to experiment and react quickly. That's a pretty useful superpower.

Test in Production (Carefully)

Staging environments are valuable. They're also never quite the same as production. Real traffic patterns. Real data volumes. Real third-party integrations. Staging approximates these things, but it doesn't perfectly replicate them.

Feature flags let you test in production in a controlled way. Enable a new feature for internal users only. Or expose it to a small percentage of real traffic. Then watch what happens.

This isn't the same as shipping broken code to everyone and hoping for the best. It's a deliberate strategy for gathering production signal before committing to a full rollout. Your users become your test environment. Just... carefully.

Instant Rollback Without a Redeployment

Traditional rollbacks require reverting a deployment. That takes time, especially when your deployment pipeline has multiple steps, approvals, and enough YAML to qualify as a cry for help.

With feature flags, rollback is just flipping a switch. If a newly released feature starts causing problems, disable it in seconds. The bad code is still in production, but it's no longer running. You've bought yourself time to investigate and fix the problem without immediately rolling back the entire deployment. Your weekend is now slightly safer.

Trunk-Based Development

Feature flags also make trunk-based development practical. Instead of maintaining long-lived feature branches, developers commit to the main branch frequently — often daily. But what happens when a feature isn't finished?

Hide it behind a flag.

The incomplete code can be merged and deployed without exposing it to users. This means developers can integrate early and often instead of maintaining massive branches that eventually collide in a spectacular merge-conflict apocalypse.

Trunk-based development can:

Reduce merge conflicts
Improve integration quality
Encourage smaller, more frequent deployments
Simplify the delivery pipeline

Feature flags are the mechanism that makes unfinished work safe to deploy.

What This Looks Like in Practice

With feature flags and continuous delivery working together, your workflow might look something like this:

Set up a flag management server so you're not editing appsettings.json in production like an animal.
Write the code. Wrap it in a flag. Merge to main.
Deploy to production with the flag off.
Enable the flag for internal users. Watch your metrics.
Gradually roll it out to a wider audience.
Fully release the feature.
Remove the flag.

Each step is reversible. Each step gives you more confidence. And if something goes wrong at any point, flip the flag and investigate. No emergency redeployment required.

The Point

Feature flags aren't just about turning features on and off. They're a key part of separating deployment from release. That separation gives your team the freedom to: