---
title: "Year Ahead Forecast Margin (YAFM / B0810) stream"
method: GET
path: "/datasets/YAFM/stream"
tags: ["BMRS Datasets"]
---

# Year Ahead Forecast Margin (YAFM / B0810) stream

`GET /datasets/YAFM/stream`

This endpoint provides year-ahead forecast margin data.

A year-ahead forecast margin is defined as the difference between yearly forecast of available generation capacity and yearly forecast of total load,
taking into account the forecast of total generation capacity, forecast of availability of generation and forecast of reserves contracted for system services.
            
This endpoint has an optimised JSON payload and is aimed at frequent requests for the data.

## Query parameters

- `publishDateTimeFrom` string, date-time, required
- `publishDateTimeTo` string, date-time, required

## Response `200`

Data retrieved

- InsightsApiModelsResponsesTransparencyDatasetRowsYearAheadForecastMarginDatasetRow[]
  - `dataset` string, nullable
  - `documentId` string, nullable
  - `documentRevisionNumber` integer
  - `publishTime` string, date-time
  - `businessType` string, nullable
  - `year` integer
  - `quantity` 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)