Features
Related Warm-up
Pre-warm related apps when traffic arrives
Apps can declare relationships so that traffic to one pre-warms another in the background.
Configuration
["api.example.com"]
address = "127.0.0.1:3001"
command = "node api.js"
health_check = "/health"
also_warm = ["frontend.example.com"]
["frontend.example.com"]
address = "127.0.0.1:3002"
command = "node frontend.js"
health_check = "/"How It Works
When a request hits api.example.com, Penny starts frontend.example.com in the background, anticipating it will be needed soon.
The warmed app gets its own idle timer — if no direct traffic arrives, it shuts down after its wait_period as usual.
Use Cases
- API + Frontend: When users hit the API, they'll likely need the frontend too
- Microservices: Warm up downstream services when an upstream receives traffic
- Multi-app sites: Start related apps together to reduce overall cold start time