# IDistributedApplicationBuilder.subscribeBeforePublish

- Module: [Aspire.Hosting](/reference/api/typescript/aspire.hosting.md)
- Defined on: [IDistributedApplicationBuilder](/reference/api/typescript/aspire.hosting/idistributedapplicationbuilder.md)
- Version: `13.4.0`
- Kind: `method`

Subscribes to the BeforePublish event, which fires before the application is published.

## Definition

```typescript
interface IDistributedApplicationBuilder {
  // ... omitted for brevity
  subscribeBeforePublish(callback: (arg: BeforePublishEvent) => Promise<void>): DistributedApplicationEventSubscription;
}
```

## Signature

```typescript
subscribeBeforePublish(callback: (arg: BeforePublishEvent) => Promise<void>): DistributedApplicationEventSubscription
```

## Parameters

- `callback` (`(arg: BeforePublishEvent) => Promise<void>`)

## Returns

[DistributedApplicationEventSubscription](/reference/api/typescript/aspire.hosting/distributedapplicationeventsubscription.md)

## Defined on

- [IDistributedApplicationBuilder](/reference/api/typescript/aspire.hosting/idistributedapplicationbuilder.md) -- `interface`