This page explains how Compute Units (CUs) are calculated for the Chain Watch API. CU costs apply to event send attempts and API operations such as creating or updating rules, variables, and targets.

> ❗️  
> ### CU usage is subject to change. Always refer to this page for the latest details.

## CU Charges for Event  
Each call send attempt consumes **10 CUs**. If delivery fails, the system retries and each retry also costs **10 CUs**.

## CU Charges for API Operations  
API endpoints incur CU costs and are applied per API request. The table below outlines the CU costs per operation:

| Endpoint Path | CU Cost | Description |  
| --- | --- | --- |  
| `/streaming/v*/targets` | 10 | Create a new target |  
| `/streaming/v*/targets/*` | 1 | Update a target |  
| `/streaming/v*/variables` | 1 | Create a new variable |  
| `/streaming/v*/variables/*` | 1 | Update a variable |  
| `/streaming/v*/variables/*/values` | 5 | Add variable values |  
| `/streaming/v*/variables/*/values/*` | 5 | Update variable values |  
| `/streaming/v*/rules` | 10 | Create a new rule |  
| `/streaming/v*/rules/*` | 1 | Update a rule |

> 👍  
> Regularly monitor your CU usage to optimize API interactions.

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