Part 9 · Hands-On

Everything in Parts 0–8 is verifiable with your own hands. This part turns the concepts into commands: you’ll run a node, talk to it over RPC, build a transaction from raw fields, verify a Merkle proof, and read the live chain — confirming for yourself what every earlier page described.

The one idea to hold onto

You don’t truly get Proof of Work, UTXOs, or Merkle proofs until you’ve watched a block confirm and traced a coin through the chain yourself. The whole ethos of Bitcoin is don’t trust, verify — and this part is where you actually do the verifying.

Use a test network while learning

Do every experiment on regtest or signet/testnet first — worthless coins, zero risk. Never rehearse on mainnet, where mistakes are irreversible. See Testnet, Signet & Regtest.

Roadmap for this part

1. Running Your Own Node — install Bitcoin Core, configure it, and become a sovereign verifier instead of trusting someone else’s.
2. Talking to Your Node with bitcoin-cli — the JSON-RPC interface: walk the chain, decode transactions, query the UTXO set.
3. Build & Decode a Raw Transaction — create, sign, and broadcast a transaction, mapping every field back to Part 2.
4. Verify a Merkle Proof Yourself — prove a transaction is in a block by recomputing the root, the way SPV clients do.
5. Testnet, Signet & Regtest — the three sandboxes for risk-free experimentation, and when to use each.
6. Reading the Live Chain & Block Explorers — inspect real blocks and transactions, and verify an explorer’s claims against your own node.

The recurring question, applied here

How does running a node help untrusting strangers agree on one ledger? (Preview: because each of them can independently check every rule, no one has to trust anyone — they each hold the whole truth and reject anything that breaks the rules.)