# 61 Finance Market Data Sources

_Last updated: 2026-05-13_

## Purpose
Market data source registry and quality rules.

## Load when
- Fetching or validating prices, volumes, crypto metrics, ETF/stocks fundamentals, automated finance analyses

## Stable facts
- CoinMarketCap API is a possible crypto data source.
- Market data is mutable and must be timestamped.

## Operating rules
- Always timestamp data and source.
- Cross-check critical prices/signals when decisions depend on them.
- Do not store API keys in markdown.
- Respect provider rate limits and licensing.

## Data sources
- CoinMarketCap API
- Official exchange APIs
- Broker exports
- ETF issuer pages
- Public finance APIs/search

## Do-not-store
- API keys, secrets, private broker session tokens
- Raw account exports unless explicitly protected

## Open questions
- Which APIs are actually configured?
- Preferred base currency and benchmark indices?