# Subscribe to events

> Subscribe to events using WebSockets.

# Subscribe to events

Use [WebSockets](../concepts/websockets.md) to subscribe to events
on the blockchain. For example, monitor an NFT smart contract to alert you when a new NFT is minted.

Stateless HTTP WebSockets are supported, however, we recommend using the WSS protocol to set up bidirectional stateful
subscriptions.

:::info
For users on [Infura's credit pricing plan](../get-started/pricing/index.md), subscribing and unsubscribing to
events using the `eth_subscribe` and `eth_unsubscribe` methods consume credits from your daily quota.
Credits are consumed for these actions to prevent spamming, even if no valuable data is sent.

View the [WebSocket pricing information](../concepts/websockets.md#pricing) for a breakdown of the costs.
:::

You need to be aware of the following when sending HTTP RPC requests:

- Silent failures - [Users need to manage client-side silent failures](https://developer.mozilla.org/en-US/docs/Web/API/WebSockets_API/Writing_WebSocket_servers#pings_and_pongs_the_heartbeat_of_websockets).
- Load balancing - Unlike HTTP requests, WSS requests are not load-balanced to the fastest possible server.
- Retries - Retrying failed WebSocket requests typically requires custom JSON-RPC ID-based tracking, whereas support for
  retrying failed HTTP requests often is automatic, or easy to configure.
- Status codes - WebSockets use its own set of [status codes](https://pkg.go.dev/github.com/gorilla/websocket#pkg-constants)
  to provide users with a disconnection reason. The service will respond with the standard
  [EVM response codes](../reference/ethereum/json-rpc-methods/index.md) for each JSON-RPC request.

## Example event subscription

The following WebSocket subscription example fires a notification each time a new header is appended to the chain:

```bash
$ wscat -c wss://mainnet.infura.io/ws/v3/<YOUR-API-KEY>
> {"jsonrpc":  "2.0",  "id":  1,  "method":  "eth_subscribe",  "params":  ["newHeads"]}
```