Nodes, networking, and Bitcoin Core

Operate and reason about the software enforcing the rules.

Follow these 10 lessons in order, or choose the topic you need. Each lesson combines an explanation, a worked example and practice inside the Guild.

1. Peer discovery and handshakes

   Nodes discover peers, negotiate services, and exchange inventory without a central network registry.

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2. Transaction and block relay

   Compact blocks, headers-first synchronization, feefilters, and relay policies reduce bandwidth and latency.

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3. Initial block download

   A new node downloads and validates historical headers and blocks before reaching the current tip.

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4. UTXO set and chainstate

   Bitcoin Core separates block storage, indexes, mempool state, and the active UTXO database.

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5. Pruning and assumeutxo

   Resource-saving modes change storage or bootstrap work without replacing final validation guarantees.

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6. RPC and ZMQ

   RPC controls a node while event interfaces support applications that need chain and mempool updates.

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7. Consensus changes and BIPs

   Soft forks tighten validity rules and require deployment coordination across users, miners, software, and markets.

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8. Code review and release process

   Bitcoin Core changes undergo adversarial review, testing, backport discipline, and reproducible release work.

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9. Full node architecture

   Connect peers, message parsing, validation, mempool, block index, chainstate, wallet, RPC, ZMQ, indexes, pruning, and reorg handling in one system map.

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10. Bitcoin P2P message bytes

    Parse network magic, command, payload length, checksum, and payload from a byte stream before applying command-specific limits and validation.

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