What a Bitcoin node does, and how to run one

What is a Bitcoin node?

There’s no central server in Bitcoin. Nodes all over the world each hold the same ledger and enforce the same rules, and they talk to each other directly. Bitcoin Core is the software most of them run.

The point is independence. A wallet connected to your own node doesn’t ask anyone whether a payment is real. It checks. That also keeps your addresses private, because you’re not telling someone else’s server which ones are yours.

What does a Bitcoin node check?

Every rule, on every block, from the first one in 2009. A block that breaks one is rejected, however much work went into it. That’s what gives miners a reason to play fair.

The work check is the cheap one: a single hash compared with the target. Proof of work shows why finding that hash is hard and checking it is instant. The reward check is why a miner can claim the block reward and fees but never a satoshi more.

Full node vs pruned node vs light client

All three talk to the Bitcoin network. The difference is how much they check for themselves and how much they keep.

A pruned node is still a full node in every way that matters for your security. It just can’t hand old blocks to a new node that’s syncing, and a few features that need the whole history, like a full transaction index, are off.

A light client, often called SPV after section 8 of the whitepaper, only checks that blocks carry enough work. It relies on full nodes to tell it about its own transactions. That’s fine for a phone, and it’s why full nodes matter: someone has to answer.

Why do miners and pools need a node?

To know what to mine. A miner can’t hash an empty idea; it needs a block template: the previous block’s hash, the transactions to include and the coinbase that pays the reward. Only a node that’s up to date can build a valid one.

Under Stratum V1, the protocol most pools still use, the pool’s node does all of this and miners just hash. Stratum V2 adds job declaration, so a miner can build templates with its own node and still be paid by the pool:

That matters because whoever builds the template decides which transactions get in. See which pools find most blocks right now in the biggest Bitcoin mining pools, and how they pay miners in mining pools explained.

How much storage does a Bitcoin node need?

All blocks together are 776 GB, and the chain grew about 83 GB over the last year. Add the chainstate on top: the database of every unspent output, which your node reads for each transaction it checks.

Pick a node type and a drive to see how long it lasts, and how long the first download takes on your connection:

Use an SSD. A node constantly reads and writes the chainstate, and on a spinning disk the first sync can take many times longer. bitcoin.org asks for at least 100 MB/s.

How do you run a Bitcoin node?

Install Bitcoin Core, let it sync, leave it running. The hardware bar is low. These are bitcoin.org’s published requirements:

1. 1

   Get Bitcoin Core

   Download it from bitcoincore.org and check the signature before you install.

2. 2

   Choose full or pruned

   Enough disk? Keep everything. Tight on space? Set a prune target in the settings; 550 MiB is the minimum.

3. 3

   Let it sync

   The initial block download fetches and checks every block since 2009. Your wallet won’t show new payments until it catches up.

4. 4

   Leave it on

   Once synced it only needs about one block every ten minutes. Open port 8333 if you want to serve other nodes too.

5. 5

   Point your wallet at it

   Many wallets can connect to your own node, so they stop asking a stranger’s server about your balance.

How much bandwidth does a node use?

Downloads are steady and small once you’re synced: a few hundred MB a day. Upload is the big one, because your node sends old blocks to new nodes catching up. bitcoin.org puts it at around 5 GB a day with default settings.

On a capped plan, Bitcoin Core’s maxuploadtarget stops serving old blocks once you hit a daily limit, and blocksonly skips relaying loose transactions. Turning off listening cuts your peers to the outbound ones. Your node still checks everything either way.

Does running a Bitcoin node earn you bitcoin?

No. Nodes aren’t paid. The block reward goes to whoever mines the block, and mining takes hashrate, which a node doesn’t have. What a node gives you is certainty that the bitcoin you receive is real, and a small, real vote for the rules you run.

If you’re curious what mining itself is like without buying a machine, the CloudMineCrypto app lets you start free: claim the free plan, add more with ads, games, offers and the daily check-in, and withdraw to your own wallet, Lightning included. Rewards are estimates and aren’t guaranteed, and a plan isn’t a share in any real machine or pool. Terms apply.

Frequently asked questions

Sources and further reading

1. Running a full node · bitcoin.org
2. Bitcoin Core system requirements · bitcoin.org
3. Operating modes: full nodes and SPV clients · Bitcoin developer documentation
4. getblocktemplate RPC reference · Bitcoin developer documentation
5. Reduce traffic: connections, upload target and blocks-only mode · Bitcoin Core
6. Stratum V2 Job Declaration Protocol · Stratum V2 working group
7. Blockchain size chart · blockchain.com
8. Bitcoin: A Peer-to-Peer Electronic Cash System (section 8, simplified payment verification) · Satoshi Nakamoto, 2008

Live figures on this page come from the CloudMineCrypto API or from the public blockchain data services named next to them, refresh on a schedule, and are labelled where they appear. This guide is educational and not financial advice. CloudMineCrypto is not an investment product; rewards in the app are estimates and aren’t guaranteed.