Fleet & Instances
How Ratelane tracks and displays your running API instances.
What is a fleet?
A fleet is the collection of all running instances of a service. Every instance that starts with the same service_name (or serviceName) joins the same fleet automatically.
This means if you run 4 replicas of my-api, they all appear together in the dashboard under one service — with individual instance-level detail available for each.
Instance identity
Each instance is identified by a combination of:
- Service name — from your config
- Device ID — a stable ID generated on first run, persisted to disk
- Instance version — optional, from your config
What you can see per instance
- Runtime (Node.js / Python) and version
- Framework (Express, Fastify, Hono, FastAPI)
- SDK version
- Uptime and last seen
- Per-route request counts and latency
- Active policy
Instance lifecycle
Instances appear in the dashboard as soon as they send their first telemetry poll. If an instance stops sending polls (e.g. it was shut down), it is marked inactive after a configurable timeout.