# Node Structure As with most blockchains, XYO Layer One is powered by a decentralized network of nodes that work together to construct, validate, and optimize the blockchain. All Nodes building and running the XYO Layer One Blockchain must comply with the XYO Protocol to achieve the desired functionality. The architecture consists of three core node types: * Block Producer Nodes * Validator Nodes * Efficiency Nodes Block Producer Nodes are responsible for producing blocks, Validator Nodes check for block compliance, and Efficiency Nodes are exactly what they're named: nodes designed to improve efficiency for other nodes and the blockchain overall. ### Block Producer Nodes Block Producer Nodes are responsible for producing blocks from the pending transactions in a shared transaction queue. Each block the node produces include the hashes of any included transactions and any elevated payloads. ### Validator Nodes Validator Nodes are responsible for a variety of validations in the XYO Layer One Blockchain. One of the most common validations they complete are Block Validations. Validator Nodes confirm blocks are valid before the slashing window for those blocks expires. This keeps Block Producers accountable, and ensures a third-party is validating their work. Once their validation is complete and results in an acceptable block or other XYOL1 component, Validator Nodes can choose to submit a participation transaction, showing the work they completed. These Participation Transactions are key to the Validator Node's reward system through the [Step Rewards Pool](/xyo-layer-one/rewards/step-rewards.md). #### Repairs Should a Validator Node detect invalid blocks or components, it can propose a repair, such as a Rollback or Replacement Repair. Should this occur, the offending node that produced the invalid material can have their stake slashed. In all the cases of accepted actions, both the action and original state remain in the blockchain for future transparency. * **Rollback Repair**: A rollback repair is the simplest, but also the most disruptive repair. This involves resetting the head of the chain back to the block before the invalid block was produced. * **Replacement Repair**: A replacement repair is a new block that supersedes the previous block. This causes state aggregators to use the new block in place of the original block. The resulting state, to be valid, must result in the aggregate state that would have existed if the byzantine block was properly processed. ### Efficiency Nodes Efficiency Nodes are broadly defined, and normally are separate nodes performing specific actions to improve the speed and congestion for the blockchain. Oftentimes, it offers an easy reference for other Nodes to use, such as reference related to XL1 transfers and gas payments. When a separate Efficiency Node is used for this, Block Producer and Validator Nodes can simply refer to the Efficiency Node's reference, improving transaction efficiency while simultaneously preventing invalid transfers from being included in blocks. --- # Agent Instructions: 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: ``` GET https://docs.xyo.network/xyo-layer-one/architecture/node-structure.md?ask= ``` The question should be specific, self-contained, and written in natural language. 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.