> For the complete documentation index, see [llms.txt](https://whitepaper.particle.network/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://whitepaper.particle.network/particle-network/modular-l1-design/modular-nodes-introduction.md).

# Modular L1 Nodes

Users are able to support the Particle Chain's decentralization and security by running a node. "Modular Node" is a collective term for various types of nodes in the Particle Chain each serving different roles. \
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Particle Network's modular design requires five types of Modular Nodes:

1. **Validator:** Responsible for validating transactions, settling the execution status of external UserOps, voting to generate blocks, and participating in the verification of fraud proofs submitted by Watchtower nodes.
2. **Relayer:** Acts as a message hub, monitoring and synchronizing the execution status of external chain UserOps and synchronizing Universal Account changes.
3. **Bundler:** Responsible for the specific execution of UserOps on external chains.
4. **DA Aggregator:** Integrates and encapsulates various DA networks such as Celestia, Avail, Near DA, and EigenDA, providing upper layers with a unified data publishing and verification interface.
5. **Watchtower:** Monitors the work of other nodes, ensuring node liveness, and provides execution proofs and possible fraud proofs for each block generated per epoch.

<figure><img src="/files/O7CeH5JgbzwGvtHQ037R" alt=""><figcaption></figcaption></figure>

### Operating Conditions

The Particle Chain is an open and permissionless Layer-1, where any node operator can freely participate as long as they meet certain conditions.&#x20;

The network will gradually open up, with more information to be provided later.