> For the complete documentation index, see [llms.txt](https://docs.tenten.co/awesome/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.tenten.co/awesome/web3/web3.0_vault-main-1/basics.md). # basics What is a node in blockchain? A node is essentially a program running on a single computer that allows you to connect with the rest of the blockchain network. It connects with other nodes to send information back and forth, checks that transactions sent between people are valid, and stores important information about the state of the blockchain. In particular, one of the peculiarities of a blockchain network is that the network is essentially composed of only nodes: that is, the physical hardware running a blockchain such as Ethereum or Bitcoin is just the collection of all the nodes around the world being run by individual people. There's no master server or single source of truth - that's why it's decentralized! There's typically two main categories of nodes - light nodes and full nodes. Light nodes sync just the block headers and request from full nodes for many queries, while full nodes keep the entire state of a blockchain - every transaction that's ever been created. Most queries work with light nodes, but full nodes are the backbone of the blockchain - they’re necessary to serve most information. * References: * --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.tenten.co/awesome/web3/web3.0_vault-main-1/basics.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.