# Bitcoin Research Kit (BRK) > Open-source Bitcoin on-chain analytics API. Thousands of metrics, block explorer, address index — all computed from a Bitcoin Core node, including the price. Base URL: https://bitview.space ## API Free, no auth required. JSON and CSV output. Mempool.space compatible for block/tx/address endpoints. - [Interactive docs](https://bitview.space/api) - [OpenAPI spec (compact, LLM-optimized)](https://bitview.space/api.json) - [OpenAPI spec (full)](https://bitview.space/openapi.json) ## Discover Search for metrics by keyword: GET /api/metrics/search/{query} Browse all available metrics: GET /api/metrics/list List available indexes (date, height, etc.): GET /api/metrics/indexes Browse the full metric catalog as a tree: GET /api/metrics ## Query Get a metric by name and index: GET /api/metric/{metric}/{index} GET /api/metric/{metric}/{index}?start=-30 Example — last 30 days of Bitcoin closing price: GET /api/metric/close/1d?start=-30 Fetch multiple metrics at once: GET /api/metrics/bulk?index={index}&metrics={metric1},{metric2} See the `MetricData` schema and query parameters (`start`, `end`, `limit`) in the [OpenAPI spec](https://bitview.space/api.json). ## Block Explorer GET /api/block-height/{height} GET /api/block/{hash} GET /api/tx/{txid} GET /api/address/{address} ## Mempool GET /api/mempool/price GET /api/mempool/info GET /api/v1/fees/recommended ## Client Libraries - JavaScript: https://www.npmjs.com/package/brk-client - Python: https://pypi.org/project/brk-client/ - Rust: https://crates.io/crates/brk_client ## Metric Categories Market, supply, mining, network activity, UTXO age bands, cointime economics, holder cohorts, cost basis distributions, and more. Use the discovery endpoints above to explore. ## Source - GitHub: https://github.com/bitcoinresearchkit/brk - License: MIT