satd provides the core node, plus the wallet-server protocols operators usually wire up alongside it (Esplora REST, Electrum, BIP 157/158).

Why satd?

• Node Sovereignty: satd puts relay policy back in the operator's hands. Every mempool and relay decision is a first-class, exposed flag — filter spam, cap or disable OP_RETURN data carriers, tune dust thresholds and ancestor/descendant limits, and decide for yourself what your node accepts and rebroadcasts (-datacarrier, -datacarriersize, -dustrelayfee, -permitbaremultisig, -limitancestorcount) — all without running a patched fork. A memory-safe Rust implementation gives economic node operators a robust alternative to the C++ monoculture, strengthening the network's resilience. Read the Manifesto.
• Built for the Operator: Eliminates the bitcoind + electrs + esplora multi-process headache — everything shares a single chainstate and a single RocksDB instance — and ships the operational surfaces you'd otherwise bolt on yourself: native Prometheus /metrics and /healthz with structured logs, a capability-scoped authentication system (cookie, user/pass, or bearer-token -authfile, with native TLS/mTLS on every listener), API scaling knobs that isolate read-only RPC onto a dedicated runtime behind admission control (--api-threads), and an optional MCP server that exposes node data and ops surfaces directly to AI agents.
• Zero Consensus Divergence (Dual Engine): Run the independent Rust consensus engine, the Bitcoin Core C++ libbitcoinconsensus engine, or both at once with runtime shadow-validation — every script cross-checked against Core (genesis→~945k, zero divergence). See Consensus & Network below for the differential test battery that holds the full block-acceptance pipeline to Core.

Features

Consensus & Network

• Dual Consensus Engine: A complete, independently written Rust consensus engine that passes the full Bitcoin Core test suite, with a C++ libbitcoinconsensus conservative fallback and runtime script-level shadow validation between the two.
• Differential Block-Acceptance Testing: Beyond script verification, the full block-acceptance pipeline (PoW, merkle/witness commitments, sigops, BIP 34, value conservation, maturity, timestamps, locktime/BIP 68) is checked against Core by static fixtures ported from Core's own tests and a generative fuzzer that dual-submits adversarial blocks to satd and a live bitcoind.
• Swarm-Style IBD: BitTorrent-like parallel block downloading and speculative verification pipeline for heavily optimized Initial Block Download.
• Full P2P: BIP 152 compact blocks, ban scoring, addrv2, BIP 324 v2 encrypted transport (-v2transport, on by default; opt-in -v2only anti-surveillance mode), Tor v3 (hardcoded .onion seeds), SOCKS5 -proxy.
• Policy Sovereignty (Mempool): Strict, first-class control over what your node relays. Easily filter spam, block OP_RETURN data, or adjust limits via exposed flags (-datacarrier, -datacarriersize, -dustrelayfee, -limitancestorcount, -permitbaremultisig) without needing a patched fork.
• Modern Mempool: Full RBF / opt-in BIP 125 and CPFP ancestor tracking.

Native Integrations (No side-cars required)

• Native TLS Support: Direct TLS support for JSON-RPC, Electrum, and Esplora servers, eliminating the need for Nginx/reverse-proxy sidecars.
• Electrum Protocol: Native TCP server (protocol 1.4) for wallets like BlueWallet, Sparrow, and Nunchuk.
• Esplora REST: Wire-shape parity with blockstream.info / mempool.space for the implemented endpoint set.
• Verified Compatibility: API surfaces rigorously tested with real client canaries in CI to ensure compatibility.
• Streaming Consumption API: A novel streaming consumption API for real-time access to chain and mempool events, with privacy-preserving options.
• AI-Native MCP Server: An optional Model Context Protocol (mcp) listener that exposes node data and operational surfaces directly to AI agents.
• Compact Block Filters: Native BIP 157/158 index and P2P service for embedded-Neutrino mobile wallets (Zeus, Blixt, Mutiny).
• Shared Indexing: Address-history index atomic with connect_block. One database powers everything.

Operator Ergonomics

• Native TUI (sat-tui): A beautiful Ratatui-based terminal interface for real-time IBD bitmap visualization, peer stats, and node observability.
• Metrics & Observability: Native Prometheus /metrics, /healthz, and JSON-structured logs.
• Core-Compatible: Accepts standard bitcoin.conf and CLI flags (-prune, -txindex, -assumevalid). Supports standard .cookie auth. AssumeUTXO fast-sync is supported via the loadtxoutset RPC (Core's snapshot files load directly). Note: While AssumeUTXO support is fully implemented and compatible with existing commonly-distributed snapshots, we do not create or distribute these snapshots ourselves; users must find their own source for trusted snapshots.
• Mempool Stream: subscribemempool JSON-RPC WS subscription with explicit eviction/replacement reasons.
• Events Bus: gRPC + ZMQ publishers for chain and mempool events (satd-events).
• Reorg Logging: Persistent reorg log with an optional webhook.

(See CORE_DIFFERENCES.md for a full catalog of intentional deviations and features explicitly out of scope, such as the legacy wallet).

Getting Started

Try it in 2 minutes (signet, Docker)

No build required — stream a live signet sync (peers connecting, blocks flowing) straight to your terminal:

docker run --rm -it -v satd-signet:/var/lib/satd \
  ghcr.io/epochbtc/satd:0.3.0 --signet --datadir=/var/lib/satd

Within seconds the node connects to signet peers and begins Initial Block Download. Query it from another terminal (signet RPC is on 38332, cookie auth):

docker exec <container> sat-cli \
  --rpcport=38332 --rpccookiefile=/var/lib/satd/signet/.cookie \
  chain info

Stop with Ctrl-C. The --rm flag discards the container on exit; drop it (and keep the named volume) to resume the sync later.

Building

Requires Rust (stable, edition 2024), a C/C++ compiler, and clang/LLVM libraries (for rocksdb-sys bindgen).

./configure          # detect dependencies, generate .cargo/config.toml
cargo build

Reproducible build via Nix (deterministic across hosts; toolchain pinned in rust-toolchain.toml):

nix build .#satd     # produces ./result/bin/{satd, sat-cli}

See the Operator Manual → Packaging for the full story.

Running

# Regtest — quick local node
cargo run --bin satd -- --regtest

# Mainnet — Esplora and address index on by default
cargo run --bin satd -- --datadir=/path/to/datadir

# Add the Electrum server (loopback; expose via Tor)
cargo run --bin satd -- --electrum=1

# Add BIP 157/158 P2P service for embedded-Neutrino wallets
cargo run --bin satd -- --blockfilterindex=basic --peerblockfilters=1

Querying & Stopping

cargo run --bin sat-cli -- --regtest getblockchaininfo
cargo run --bin sat-cli -- --regtest getindexinfo
cargo run --bin sat-cli -- --regtest getserverstatus
cargo run --bin sat-cli -- --regtest stop

Configuration

Drop in your existing Bitcoin Core bitcoin.conf. satd reads Core's config surface directly (-regtest, -datadir, -rpcport, -prune, -txindex, -assumevalid, -includeconf, …); names and semantics are pinned to Core v30. Commonly-used options are honored; a recognized v30 option satd doesn't implement is skipped with a startup warning (the node still starts) rather than aborting; a small set whose silent omission would mislead about security/exposure/privacy stays fatal with guidance; and unknown keys are rejected as typos. Nothing a config asks for is silently ignored. See the Configuration Flag Reference for the per-key disposition.

Bundled --profile=<preset> selects from archival, pruned-home, mining, regtest-dev, and signet-watchtower. CLI flags override profile values; getconfig / sat-cli node config shows the effective post-merge configuration.

By default, authentication uses a cookie file (default) or --rpcuser / --rpcpassword. See also the Authentication page for more details. The Esplora listener defaults to unauthenticated loopback; for non-loopback exposure, set --esploraauth=cookie or --esploraauth=userpass.

See the Operator Manual for the full flag matrix and tuning notes — in particular the Configuration Flag Reference.

Repository Layout

satd/                         Daemon binary — config, lifecycle, wiring
sat-cli/                      CLI client — Bitcoin-Core-compatible RPC client
sat-tui/                      Ratatui-based ops TUI
node/                         Core library (chain, storage, mempool, P2P, RPC, validation)
node-index/                   Address-history index over the shared RocksDB
node-filter-index/            BIP 158 compact-block-filter index
esplora-handlers/             Native Esplora-compatible REST
electrum-proto/               Native Electrum protocol server (vendored from electrs)
events/                       Event-bus sinks (gRPC + ZMQ)
mcp/                          MCP tools over the ops-surface RPCs
consensus/                    Rust script-verifier shadow
block-analyzer/               Standalone tool for offline block analysis
docs/                         API + integration docs

Documentation

License

MIT — see LICENSE for the full text.

Vendored code from romanz/electrs (MIT) is attributed in electrum-proto/vendor/electrs.MIT with original LICENSE text preserved.