Bitcoin full node in Rust aimed at production server-side use: multi-peer IBD, tip follow, block/tx relay (tip mode), optional Core-class JSON-RPC, and in-process Electrum + optional Esplora REST for wallet clients (scripthash index via --shindex, default off; not a graphical block-explorer stack) — built around a libbitcoin-class relational archive and a pure-Rust consensus/script path.

0.5.1 is the current named published 0.x line (GitHub Release: Linux musl + Windows CRT-static + Darwin aarch64). Not 1.0: schema can still refuse a named wipe (SCHEMA.md, OPERATOR.md); default mainnet --milestone 840000 skips historical script/sig checks (--milestone 0 is full scripts); Electrum/Esplora need --shindex (default off) after tip. Run signet first, then mainnet with monitoring. Report security issues privately: SECURITY.md. Runbook: docs/experimental-mainnet.md.

Most full nodes center a UTXO set + block files (Bitcoin Core). Most Electrum backends are external indexers of another node. rbitcoin does neither: no UTXO set (libbitcoin-class archive), Electrum + txindex in-process.

Operator-order facts (mainnet tip moves; treat as ballpark, not a warranty):

• ~200 GiB hot pin/annotate set after schema 17 (txout + spent + idx + txid + tx.head); ~700 GiB if you keep cold inwit for reconstruct. Optional --shindex is extra (Electrum/Esplora require it; on/off costs in OPERATOR.md). Ballpark, not a warranty — census in SCHEMA.md
• Core-class JSON-RPC subset (default off): docs/rpc.md
• Under ~30 h IBD on a laptop-class host with --milestone 0 (full scripts)
• Modest RAM during sync — no multi‑GiB dbcache, no long “flush the cache” pauses (confirm is lookup → load → scripts → write)
• Segmented tx.head — newer txs resolve hottest (tip-local traffic wins)
• Pure-Rust consensus/scripts on rust-bitcoin (no libbitcoinconsensus)
• Reproducible static musl builds for ordinary Linux hosts

1. On-disk archive — map-free Class A/B/C tables (pread/pwrite + fallocate grow; kernel page cache as L0): split Class A (txout / inwit / spent), keyless tx.head, spend annotations, native scripthash. Historical blocks are reconstructed from the archive; tip serve / reorg uses the in-RAM body queue and peer wire. Confirm/mempool prevouts use the archive (and in-mempool parents), not a separate UTXO hash table. Layout: SCHEMA.md; IO: docs/io-modality.md; concurrency: docs/concurrency.md.
2. Concurrent IBD / IO — fixed writer roles (one Class A appender), allocate-then-publish HWMs (no map epochs), confirm as lookup → load → scripts → write, bulk io_uring where available (pread/pwrite fallback). Linux-shaped IO; porting needs work. Map: docs/concurrency.md.
3. Pure-Rust consensus — structure, connect, and script verification in Rust; only secp256k1 (via rust-bitcoin) as the crypto primitive — no libbitcoinconsensus dual-eval. Tests: docs/consensus-tests.md.

Full narrative and Core / Fulcrum contrasts: docs/architecture.md. Product surface: COMPAT.md.

Core pipelines exist (store, consensus, P2P IBD, tip follow, scripthash, Electrum, Esplora REST, libre mempool) for the server-side / wallet-client backend role. 0.5 mainnet is early production / high-scrutiny — not a Core or Fulcrum replacement, not a soak badge. Run signet first, then mainnet with monitoring (OPERATOR.md). First hour on regtest (mine → Electrum → Esplora): OPERATOR.md. Finishing any one operator’s first full mainnet sync is not a gate for using or packaging this tree. 1.0 gates: docs/road-to-1.0.md.

Non-goal: powering a graphical block explorer (search boxes, address-prefix autocomplete, explorer-only catalogue APIs). Product surface: COMPAT.md.

Authorship: first-party code is AI-written (Grok / xAI) under Brandon Black (@reardencode) prompting — details in SECURITY.md.

Milestone (default mainnet 840000): at/below --milestone, script/sig checks are skipped on block connect (assumevalid-style speed tradeoff). Prevouts, double-spend, maturity, and fees still run. Use --milestone 0 for full script validation.

# Portable static release (preferred)
nix build .#rbitcoin-musl
install -m 755 result/bin/rbitcoin-node result/bin/rbitcoin-cli target/release/

# Signet lab (time-boxed)
./target/release/rbitcoin-node --datadir ./datadir-signet --network signet \
  --listen 127.0.0.1:38333 --milestone 200000 --max-run-secs 120

Custom Signets are supported with --signetchallenge and --signetblocktime; see the custom Signet example.

Pinned nixpkgs + Cargo.lock produce a fully static, portable rbitcoin-node / rbitcoin-cli (musl) that runs on ordinary Linux hosts without Nix or a matching glibc. Byte-identical digests for a given revision + target. Not NixOS-specific — any machine with Nix + flakes:

nix build .#rbitcoin-musl          # default package; fully static
# or: ./scripts/repro-build.sh
install -m 755 result/bin/rbitcoin-node result/bin/rbitcoin-cli target/release/
./scripts/repro-build.sh           # day-to-day musl install (crane-layered)
./scripts/repro-check.sh           # release only: two clean rebuilds; compare digests

Do not use cargo build --release inside nix-shell / nix develop as the operator binary — that links against the Nix store glibc and fails outside the store (No such file or directory at exec). Details: docs/reproducible-builds.md.

Requires Rust 1.95 (workspace rust-version, matching Nix/CI). Prefer the same pin as release builds for tests and clippy:

nix develop   # or: nix-shell  (both use flake.lock, not floating <nixpkgs>)
cargo build --workspace
cargo test --workspace
./scripts/coverage.sh   # PR bar (Actions); see CONTRIBUTING.md / AGENTS.md

Agents implement on a worktree branch and let GitHub Actions run the workspace/coverage gates — see AGENTS.md.

Operator binary: always the static install under ./target/release/ (or ./result/bin/), or the GitHub Release for a v*.*.* tag. PR CI smokes Windows / Darwin store IO; it does not package zips. Operator knobs: OPERATOR.md. Experimental mainnet: docs/experimental-mainnet.md.

Full map (one owner per fact): docs/README.md.

Design uniqueness: docs/architecture.md. Security contact: SECURITY.md.

• Production multi-tenant Electrum or “drop-in Core”
• Wallet, mining, GUI, or pruning
• Full Core JSON-RPC surface
• A claim of complete mainnet script validation under the default milestone (use --milestone 0 for full scripts)
• A multi-OS port — Linux is the supported IO target today

Licensed under either of:

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions. See CONTRIBUTING.md.