# GET /opportunities/:opportunity_id/billing-parties

**Resource:** [Opportunities](./opportunities.md)  
**MCP tool:** `list_opportunity_billing_parties`  
**Scopes:** `opportunities:read`, `invoices:read`  
**Write operation:** no

List the billing parties (payer companies) on an opportunity. A billing party is a separate company that pays the fees for this matter; invoices raised to it surface on this opportunity in addition to the client’s, without changing who the client is.

## Parameters

| Name | In | Type | Required | Description |
|------|----|------|----------|-------------|
| `opportunity_id` | path | string | yes |  |

## Request example

```bash
curl   "https://api.trustpager.com/functions/v1/api/v1/opportunities/:opportunity_id/billing-parties"   -H "Authorization: Bearer YOUR_API_KEY"
```

---
Base URL: `https://api.trustpager.com/functions/v1/api/v1` — Auth: `Authorization: Bearer YOUR_API_KEY`