feature flag by region

If you want to implement a feature flag by region, the usual pattern is:

1. Define the regions you care about

Examples:

• US
• EU
• UK
• APAC

2. Store the user’s region

You can determine region from:

• user profile setting
• billing country
• IP geolocation
• account locale
• app/device locale

3. Use the region in flag evaluation

Example logic:

function isFeatureEnabled(user, flagName) {
  if (flagName === "new_checkout") {
    return ["US", "CA"].includes(user.region);
  }
  return false;
}

4. Keep it configurable

Instead of hardcoding, store rules in config:

{
  "new_checkout": {
    "enabled_regions": ["US", "CA"]
  }
}

Then evaluate:

function isEnabled(flagConfig, userRegion) {
  return flagConfig.enabled_regions.includes(userRegion);
}

5. Consider edge cases

• What if region is unknown?
• What if a user travels?
• What if region should be based on account country vs current location?
• Do you need compliance-based blocking (e.g. GDPR, export restrictions)?

Example rule set

• Enable in US, CA
• Disable in EU
• Roll out 10% in APAC

Best practice

Use a feature flag system that supports targeting rules like:

• region
• country
• locale
• user segment
• percentage rollout

If you want, I can also show:

• a database schema for region-based flags,
• an implementation in JavaScript / Python / Go,
• or how to do this in LaunchDarkly / Unleash / Firebase Remote Config.