---
agentTools:
  projectIndex: https://docs.rainway.com/llms.txt
---

# Node.js SDK - ConnectOptions.externalId

[Home](https://docs.rainway.com/reference/about) > [@rainway/native](nodejs-sdk) > [ConnectOptions](./nodejs-sdk-connectoptions) > [externalId](./nodejs-sdk-connectoptions-externalid)

## ConnectOptions.externalId property

An (optional) identifying string that your application can recognize and tie back to a user.

<b>Signature:</b>

```typescript
externalId?: string;
```