Feature Flags for Safer Deploys

Separate Deployment from Release

Deploy code anytime. Release features when ready.

Basic Implementation

// config/features.php
return [
    'new_checkout' => env('FEATURE_NEW_CHECKOUT', false),
    'dark_mode' => env('FEATURE_DARK_MODE', true),
];

// Usage
if (config('features.new_checkout')) {
    return view('checkout.new');
}
return view('checkout.old');

User-Based Flags

class FeatureFlag
{
    public static function enabled(string $feature, ?User $user = null): bool
    {
        $flag = self::find($feature);

        // Global flag
        if ($flag->enabled_for_all) return true;

        // User-specific
        if ($user && $flag->users->contains($user->id)) return true;

        // Percentage rollout
        if ($user && $flag->percentage > 0) {
            return (crc32($user->id . $feature) % 100) < $flag->percentage;
        }

        return false;
    }
}

In Templates

@feature('new_checkout')
    <x-new-checkout />
@else
    <x-old-checkout />
@endfeature

Gradual Rollout

Day 1: 5% of users
Day 3: 25% of users
Day 5: 50% of users
Day 7: 100% of users

Monitor metrics at each stage.

Testing

public function test_new_checkout_flow()
{
    // Enable flag for test
    config(['features.new_checkout' => true]);

    $response = $this->post('/checkout', $data);

    $response->assertOk();
}

Clean Up Old Flags

Flags are debt. Remove when:

• Feature is 100% rolled out
• Feature is permanently removed

// TODO: Remove after 2024-02-01 when new_checkout is default
if (Feature::enabled('new_checkout')) {

Services

For more features, consider:

• LaunchDarkly
• Split
• Flagsmith
• Laravel Pennant