# How to Embed a Node in Your Application

Use the `ant-node` API when your Rust application needs to own a node runtime directly.

## Prerequisites

* Rust toolchain
* A Rust application that can own an async node task for the life of the process
* A rewards address for production node operation

## Steps

### 1. Add ant-node

Use the published `ant-node` crate from crates.io:

```toml
[dependencies]
ant-node = "0.11.0"
tokio = { version = "1", features = ["full"] }
```

The crate enables its `logging` feature by default. If you opt into `default-features = false`, add `features = ["logging"]` explicitly when you still want tracing output from the node runtime.

### 2. Build a node with the API

For local or development embedding, start from the development preset:

```rust
use ant_node::{NodeBuilder, NodeConfig};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut config = NodeConfig::development();
    config.root_dir = "./embedded-node".into();

    let mut node = NodeBuilder::new(config).build().await?;
    node.run().await?;
    Ok(())
}
```

### 3. Subscribe to node events

`RunningNode` exposes event subscriptions.

```rust
let mut node = NodeBuilder::new(NodeConfig::development()).build().await?;
let mut events = node.subscribe_events();

tokio::spawn(async move {
    while let Ok(event) = events.recv().await {
        println!("{event:?}");
    }
});
```

### 4. Configure production settings explicitly

`NodeConfig::default()` is production-oriented and expects real rewards configuration. The config includes fields such as:

* `root_dir`
* `port`
* `ipv4_only`
* `bootstrap`
* `network_mode`
* `testnet`
* `upgrade`
* `payment.rewards_address`
* `payment.evm_network`
* `bootstrap_cache`
* `storage`
* `close_group_cache_dir`
* `max_message_size`
* `log_level`

`payment.evm_network` can target `ArbitrumOne`, `ArbitrumSepolia`, or a private EVM with `Custom { rpc_url, payment_token_address, payment_vault_address }`.

Treat that list as a practical overview rather than a complete contract. For the full config surface, see the [ant-node API](https://github.com/WithAutonomi/ant-node).

## Verify it worked

The node is running when `node.run().await?` starts successfully, the runtime binds to a port, and your event subscriber begins receiving node events.

## Common errors

**Missing rewards configuration in production mode**: The builder rejects production nodes without `payment.rewards_address`.

**Multiple identities under the default root**: Use an explicit `root_dir` if you do not want identity auto-discovery under the default node directory.

**Node task blocks the rest of the app**: Put your application orchestration around the async node task instead of expecting `run()` to return immediately.

## Next steps

* [System Overview](/developers/architecture/system-overview.md)
* [Deploy to Mainnet](/developers/guides/deploy-to-mainnet.md)
* [Core Concepts Overview](/developers/core-concepts/overview.md)


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