# Time-series telemetry

> Overview of how ZAPP represents time-series telemetry inside listener pipelines and gRPC APIs.

---

LLMS index: [llms.txt](/datacenter/zapp/llms.txt)

---

ZAPP represents decoded sensor telemetry as time-series models. Operators usually interact with this model indirectly through pipeline components, the ZAPP Aggregator, and gRPC subscriptions.

A time-series model contains:

- `readings`, which group telemetry by sensor ID
- Instance readings, which represent individual samples
- Window readings, which represent aggregated samples over a time interval
- `snapshots`, which represent the latest known values for multiple sensors at one timestamp

Pipeline components use time-series models when telemetry has been decoded and associated with the sensor manifest. For example, `payloadProcessor` converts NVIDIA time-series payloads into `*timeseries.Model` values, and `redfishCollector` emits `*timeseries.Model` values from Redfish polling.

Terminal components then decide where those models go. `aggregatorStreamer` sends them to the ZAPP Aggregator, while `grpcServer` exposes them directly to gRPC consumers.