---
title: "System frequency (FREQ) stream"
method: GET
path: "/datasets/FREQ/stream"
tags: ["BMRS Datasets"]
---

# System frequency (FREQ) stream

`GET /datasets/FREQ/stream`

The endpoint provides data that has been received every 2 minutes the transmission system frequency, expressed as a hertz value for one or more spot times within that 2 minute period.
The default output will be the latest published data.

This endpoint has an optimised JSON payload and is aimed at frequent requests for the data.

## Query parameters

- `measurementDateTimeFrom` string, date-time
- `measurementDateTimeTo` string, date-time

## Response `200`

Data retrieved

- InsightsApiModelsResponsesMiscDatasetRowsSystemFrequency[]
  - `dataset` string, nullable
  - `measurementTime` string, date-time
  - `frequency` number, double

## Other responses

- `400` — Error with query parameters - see response for details
- `429` — Too many requests
- `500` — Server error - please try again later

---

[API](https://skmtc.net/elexon/apis/bmrs-insights.md) · [All operations](https://skmtc.net/elexon/apis/bmrs-insights/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/elexon/bmrs-insights/versions/d94e9edb295e/schema)