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FitMe — Fitness Platform
A subscription-based military fitness platform with a custom WordPress backend, Stripe billing, member dashboards, and a workout-progression engine — handling 50k+ requests/minute with aggressive caching.
Hero Screenshot
Role
Full-stack Developer
Timeline
16 weeks
For
FitMe GmbH
Status
Live — 3400+ users
Architecture
System Design.
The platform needed to serve adaptive workout plans to thousands of concurrent users while keeping the CMS accessible for non-technical trainers. I chose a headless WordPress backend serving a REST API through a Redis-cached layer, with a lightweight JavaScript front-end.
The core stack:
1
WordPress + ACF
Custom post types, flexible blocks
2
Redis + Varnish
Sub-50ms API responses
3
Stripe Connect
Subscriptions + usage billing
4
Docker Compose
CI/CD → DO Droplet
Workout Progression Engine.
The core logic — a PHP class that calculates the next workout volume based on the user's previous performance, fatigue level, and their progression phase.
class WorkoutProgressionEngine {
private int $volume;
private float $fatigueFactor;
public function __construct(
private array $user,
private array $previousSession
) {
$this->volume = $previousSession['total_volume'] ?? 0;
$this->fatigueFactor = $this->calculateFatigue();
}
public function nextWorkout(): array
{
$multiplier = match ($this->user['phase']) {
'base_building' => 1.05,
'intensity' => 0.90,
'peak' => 1.02,
default => 1.00,
};
return [
'exercises' => $this->generateExercises($multiplier),
'total_volume' => (int) ($this->volume * $multiplier * $this->fatigueFactor),
'rest_days' => $this->fatigueFactor < 0.85 ? 2 : 1,
];
}
private function calculateFatigue(): float
{
$daysSinceLast = (new DateTime())->diff(
new DateTime($this->previousSession['date'])
)->days;
return min(1.0, 0.6 + ($daysSinceLast * 0.08));
}
}Results
Performance & Impact.
3400+
Active members
~60ms
Avg. API response
50k/min
Peak throughput