SourceCrawler
LINK::LIVEUTC::--:--:--TIP_BLOCK::fetching…HASH::—REACHABLE::—QUEUE::—LAST_CYCLE::—SNAPSHOTS::—REGIONS::—BITNODES.OBSERVER // —

What is a Bitcoin node?

A primer for everyone — from someone learning Bitcoin for the first time, to someone deciding whether to run a node.

The short version

A Bitcoin node is software that downloads and verifies the full Bitcoin blockchain, then participates in the peer-to-peer network — relaying transactions, serving blocks to other peers, and independently enforcing the consensus rules.

There is no central server. The network is the sum of these nodes agreeing on the same set of rules. The more independent nodes there are, the harder it becomes for any single party — a government, a mining cartel, an exchange — to change those rules.

Sovereignty
When you run your own node, you trust no one to tell you what your balance is or which transactions are valid. You verify it yourself.
Network health
Reachable nodes are the backbone of P2P bootstrap. New nodes learn the network from existing peers.
Censorship resistance
Geographically and politically diverse nodes make it hard to silence the network in any one jurisdiction.
Privacy
Your own node lets you query the blockchain without leaking which addresses are yours to a third-party block explorer.
How does Bitnodes know about your node?
The crawler in a nutshell

The Bitnodes crawler starts from a list of DNS seeders, opens a TCP connection on port 8333 (mainnet) to each peer it learns about, performs the Bitcoin version handshake, and asks getaddrfor more peers. Each successful handshake adds your node to the “reachable” set.

Snapshots are written once per crawl cycle as JSON files. The dashboard you’re looking at reads those files plus live Redis state.