# Caching {#caching}


Caching strategies using Redis and in-memory caching.


## Redis Configuration {#redis-configuration}


```bash
REDIS_ENABLED=true
REDIS_URL=redis://localhost:6379
```


## Cache Layers {#cache-layers}


| Layer         | Scope        | TTL               | Use Case                       |
| ------------- | ------------ | ----------------- | ------------------------------ |
| **In-memory** | Per-instance | Short (1-5 min)   | Frequently accessed configs    |
| **Redis**     | Shared       | Medium (5-60 min) | Session data, computed results |
| **Response**  | Per-request  | Varies            | HTTP cache headers             |


## NestJS Cache Manager {#nestjs-cache-manager}


```typescript
@Injectable()
export class EmployeeService {
  constructor(@Inject(CACHE_MANAGER) private cacheManager: Cache) {}

  async getEmployee(id: string): Promise<IEmployee> {
    const cacheKey = `employee:${id}`;
    const cached = await this.cacheManager.get<IEmployee>(cacheKey);
    if (cached) return cached;

    const employee = await this.repository.findOne(id);
    await this.cacheManager.set(cacheKey, employee, 300); // 5 min TTL
    return employee;
  }
}
```


## Cache Invalidation {#cache-invalidation}


Invalidate on mutations:

```typescript
async updateEmployee(id: string, input: UpdateEmployeeDTO) {
  const result = await this.repository.update(id, input);
  await this.cacheManager.del(`employee:${id}`);
  return result;
}
```


## Related Pages {#related-pages}


- [Performance Overview](https://sourcey-gauzy.pages.dev/performance/performance-overview/index.md)
- [Database Optimization](https://sourcey-gauzy.pages.dev/performance/database-optimization/index.md)