mempool.space

mempool.space is the reference Bitcoin block + mempool explorer — fully open-source, self-hostable on a Raspberry Pi or VPS, with first-class Tor support and a live UI that shows fee market dynamics, miner stats, lightning network visualisation, and full block / address / transaction inspection. Listed at Grade A · editor's pick because it's the explorer privacy-aware Bitcoiners actually run themselves (or use over Tor) instead of feeding their address-history through Blockchain.com, BlockCypher, or Blockstream-managed explorers that log queries.

Background. Created and maintained by Mempool Space K.K. (a Tokyo-based for-profit company funded by Bitcoin / Lightning enterprise sponsors), with the core codebase released under AGPLv3 at github.com/mempool/mempool. Active development since 2019; the codebase has been adopted as the default block explorer in Umbrel, Start9 / embassyOS, MyNode, Citadel, BTCPay Server, and most other "Bitcoin node-in-a-box" distributions — meaning a sizeable share of the world's privacy-aware Bitcoiners are running mempool.space code as part of their personal node stack. The public-facing instance at mempool.space serves as a polished reference deployment and runs Tor onion mirror operator-published at mempoolhqx4isw62xs7abwphsq7ldayuidyx2v2oethdhhj6mlo2r6ad.onion.

What you trust (two deployment modes). Self-hosted (the privacy-preserving mode): install mempool.space alongside your own bitcoind node — the explorer queries your local node, no external service sees your address lookups or which blocks you're inspecting. This is the trust-minimised mode, recommended for any user inspecting their own wallet addresses or constructing privacy-sensitive transactions. Public instance: using mempool.space directly is a query-time exposure to the operator (Mempool Space K.K.) — they see the IP + the addresses / transactions / blocks you look up. The operator's privacy policy commits to not selling or retaining individual lookup data, but the standard caveat applies: trust the policy until you've audited it. Tor mode mitigates the IP-association leak but the operator still sees what queries are being made from that Tor circuit's connection. The operator infrastructure itself: Mempool Space K.K. is a corporate entity in Tokyo — accept that legal compulsion to disclose query logs exists structurally, regardless of policy.

Operational specs. Self-host installation: Docker Compose, native Node.js install, or bundled in Umbrel / Start9 / MyNode / Citadel / BTCPay Server (the "easy mode" for privacy-aware Bitcoiners). Hardware: a Raspberry Pi 4 + 1 TB SSD is the typical Umbrel-class deployment; full-fat installations on VPS or workstation also documented. Features: live mempool with fee bucket visualisation, full-block view with transaction inspection, address-level activity (with privacy caveats — see Caveats), miner ranking + recent-block-discoverer attribution, lightning network graph + node + channel inspector, accelerator service (paid via Lightning to prioritise stuck transactions), API at /api for programmatic access. No native Monero support — Bitcoin (and Bitcoin-derived chains like Liquid) only; the project's scope is firmly within the BTC ecosystem. Public-facing instance is at mempool.space; Tor onion is operator-published.

Philosophy. mempool.space's editorial differentiator is the "explorer infrastructure as personal infrastructure" architecture. Where Blockchain.com / Etherscan / BlockCypher monetise by aggregating user queries (and the operator becomes a single chokepoint for surveillance of who's looking up what), mempool.space's primary deployment model is you run the explorer yourself. The public mempool.space instance exists, is excellent, and is a real product — but the project's design intentionally makes it a reference deployment rather than the canonical chokepoint. By bundling into Umbrel / Start9 / BTCPay etc., the team has effectively distributed Bitcoin block-explorer infrastructure to thousands of independent operators, no one of which sees more than their own users' queries. That's the right shape for a privacy-respecting public-good utility.

Grade rationale. Grade A and editor's pick reflect: open-source AGPLv3 codebase with active corporate-backed development; structurally privacy-preserving self-host architecture; first-class Tor support on the public instance; default-bundled inclusion in the major Bitcoin self-hosting distributions (Umbrel, Start9, MyNode, Citadel, BTCPay Server); polished, feature-complete UI that doesn't sacrifice power-user depth; documented API for programmatic integrations; no observed governance or supply-chain incidents in the last 24 months. Last verified 2026-05-13.

Useful when. You're running your own Bitcoin node and want a polished local explorer instead of querying a third-party service. You're privacy-conscious about Bitcoin-address activity and don't want every chain inspection logged at a centralised explorer. You're using Umbrel, Start9, MyNode, Citadel, or BTCPay Server — you already have mempool.space running, just open it from your local node dashboard. You're a developer building a Bitcoin app and need a reliable, well-documented API for chain data without paying enterprise pricing to Chainalysis / Glassnode. You're learning Bitcoin and want the best fee-market / mempool / mining UI in the ecosystem.

Caveats. Address activity is public on Bitcoin — mempool.space surfaces what's already on the chain; it doesn't add a privacy leak that wouldn't otherwise exist *for that specific lookup*, but the act of looking up an address can leak which addresses *you care about* to the explorer operator. Self-host to eliminate this. No native Monero support — for XMR chain inspection use a Monero block explorer (e.g., xmrchain.net or moneroexplorer.org); mempool.space is Bitcoin-only by design. Public-instance queries are observable to the operator — mempool.space (corporate entity in Tokyo, Mempool Space K.K.) can see your queries; Tor mitigates IP correlation but the query-content surface is still there. Self-host requires a synced bitcoind — the explorer is a frontend; you need a running Bitcoin full node behind it for the chain data. This is non-trivial first-time setup (days for initial blockchain sync, ~600 GB disk for full archival nodes, less for pruned). Sponsor-funded development model — mempool.space sells enterprise support and accepts corporate sponsors; the public product remains AGPLv3 but the corporate-customer roadmap is not user-visible. For ethical-fundamentalist users this is a consideration; for most users it's a non-issue because the codebase is open and self-hostable. Accelerator service is custodial-during-the-window — the paid-Lightning fee-bump feature relies on the operator brokering the transaction acceleration; not a privacy property of mempool.space's core function but worth knowing if you use the accelerator.