# Cookbook

> For AI agents: the complete documentation index is at
> [https://docs.retrocast.com/llms.txt](https://docs.retrocast.com/llms.txt) — every page is also available as
> markdown by appending `.md` to its URL.

Worked examples of common requests. Each one is a complete request body for
the beta endpoint,
`POST https://api.retrocast.com/v1-beta/forecast?model=t0-alpha`, using the
same `TsFamilyForecastQuery` shape as the
[Introduction](/api-v1/contents/intro) — only the fields each example needs
change. The `model` query parameter is required on every call. Every page
ends with a "What comes back" section showing the response.

- [Forecast several columns at once](/api-v1/contents/cookbook/multiple-targets) —
  predict sales and returns in the same request.
- [Group rows before forecasting](/api-v1/contents/cookbook/hierarchy-rollups) —
  your data is per store, you want a forecast per city.
- [Backtest on past dates](/api-v1/contents/cookbook/backtesting) —
  re-run the forecast from several points in the past and score it.
- [Send a parquet file](/api-v1/contents/cookbook/parquet-sources) —
  upload the data instead of putting rows in the request body.
- [Add extra data like weather or prices](/api-v1/contents/cookbook/covariates) —
  attach a second table and match it to yours by key.

---

Every field used here — and the ones these examples leave out, like
hierarchies of covariates — is described in the
[API Reference](/api-v1/contents/api-reference). If something doesn't work
the way these examples suggest, email support@theforecastingcompany.com.