mempool.space
Open-source mempool explorer + REST/WebSocket APIs. Industry-leading mempool visibility.
Repo: github.com/mempool/mempool.
Features
- Mempool blocks projection: shows next ~10 blocks with median fees per virtual block.
- Fee estimates:
/api/v1/fees/recommendedreturns{fastestFee, halfHourFee, hourFee, economyFee, minimumFee}. - Address history: similar to Esplora.
- Lightning visualizer: graph view, channel info.
- Mining stats: pool distribution, block templates, hashrate.
- Accelerator: paid service to push tx into next block.
Self-host
docker compose up -d
Stack: Bitcoin Core + electrs-fork (mempool-electrs) + Node.js backend
- Nginx + frontend.
Disk ~1-2 TB, RAM ~4-8 GB recommended.
REST API
GET /api/v1/fees/recommended
GET /api/mempool
GET /api/v1/fees/mempool-blocks
GET /api/tx/<txid>/status
GET /api/block/<hash>
GET /api/address/<addr>
GET /api/v1/mining/pools/24h
Full docs: mempool.space/docs/api/rest.
WebSocket
/api/v1/ws — subscribe to live blocks, mempool, address.
const ws = new WebSocket("wss://mempool.space/api/v1/ws");
ws.send(JSON.stringify({ action: "want", data: ["blocks", "mempool-blocks"] }));
Accelerator
Paid via Lightning. Operator publishes the tx with high fee priority (via mempool.space's pool partnerships). Useful when:
- Tx is stuck due to ancestor / no RBF.
- Need confirmation in next 1-2 blocks.
Cost: usually few dollars to ~$50, depending on size + urgency.
Compared to Esplora
| Aspect | mempool.space | Esplora |
|---|---|---|
| Mempool detail | best | basic |
| Fee estimation | best | OK |
| Lightning view | yes | partial |
| Mining stats | rich | basic |
| API spec compatibility | mempool.space-specific | spec defined |
Common bugs
- Self-hosted: full sync takes days; first IBD + indexing.
- Public API rate-limited; for serious integrations, run your own or pay for premium.
- WebSocket reconnect logic essential — connections drop.