# Per-metric data definitions

September 2026 · API

Every metric whose chart has a published description now carries a written definition you can request on the API and read on the per-chart docs pages. Methodology version 2026-09-06.

## What's new

Many Newhedge metrics now carry a written definition: what the number means, what its timestamp marks, whether past values can change, the universe behind the series, and the source.

## Methodology

Ask for a definition by adding `include=definition` to a metric, price history, or candles request. The response arrives as `{"definition": ..., "data": ...}` with the usual body under `data`.

The same definition is printed on the per-chart API documentation pages, the price page, and the candles page. AI assistants can request it through the MCP server. The API catalog marks which metrics have one with `has_definition`, and `units_source` says where a unit label came from.

Every metric whose chart has a published description now has a definition, and `definition_source` tells you which kind you received: a declared one, which adds the revision policy, the universe, and the source, or one built from the chart's own description.

Declared today: futures open interest (per venue and total), spot Bitcoin ETF flows, AUM, and holdings, stablecoin supply, exchange reserves, and the daily BTC price.

Covered today: futures open interest (per venue and total), spot Bitcoin ETF flows, AUM, and holdings, stablecoin supply, exchange reserves, and the daily BTC price. Methodology version 2026-09-06.

## Related

- [API documentation](https://docs.newhedge.io/api)