# Deployment behavior and environments

Learn how deployed Connect applications behave and which environments you can deploy them to.

## Application behavior and limitations

When deployed, [Connect applications](/connect/overview.md#connect-applications) have the following behavior based on their application type.

### Service

- Uses HTTP-based exposed endpoints.
- Application request times out after 5 minutes.
- Scales automatically based on the number of requests.

### Event

- Uses a message broker service.
- The event acknowledgment timeout for an application is 10 seconds.
- Application request times out after 5 minutes.
- The delivery promise is at-least-once delivery with no ordering guarantees.
- The message queue discards a message from a Subscription as soon as the message is acknowledged.
  - Unacknowledged messages are retained for 7 days.
- The message queue retries the message if the application responds with any response code other than `102`, `200`, `201`, `202`, or `204`.
  - Push backoff applies if the application responds with too many negative acknowledgments.
- Scales automatically based on the number of events being processed.

### Job

- Uses a cron-based scheduler service.
- The default schedule is defined by the `properties.schedule` cron expression in `connect.yaml`. You can override it per deployment using the `schedule` field of [DeploymentConfigurationApplication](/connect/deployments.md#deploymentconfigurationapplication).
- Application request times out after 30 minutes.

### Merchant-center-custom-application

- Is a hosted React application.
- Application request times out after 5 minutes.
- Scales automatically based on the number of requests.

### Merchant-center-custom-view

- Is a hosted React application.
- The server times out after 5 minutes.
- Scales automatically based on the number of requests.

### Assets

- Hosts static assets.
- Application request times out after 5 minutes.
- CDN capabilities are supported.

## Environments

The [DeploymentType](/search.md?urn=ctp:connect:type:DeploymentType) lets you control which type of environment your ConnectorStaged or Connector is [deployed](/connect/overview.md#deployments) to.

Deployments are made to the `sandbox` environment by default if no other type is specified. These deployments automatically scale down to zero when they are unused for a while. This can cause timeouts because they require approximately 15 seconds to boot up again.

### Sandbox

The `sandbox` deployment type is the default deployment type for Connectors. It allows you to run your Connector in a non-production environment, such as a development or QA environment.

You cannot deploy a ConnectorStaged to a sandbox environment.

### Preview

The `preview` deployment type lets you test your ConnectorStaged during application development. It allows you to validate your logic and make sure the functionality works as expected.

You must set the ConnectorStaged `isPreviewable` status to `true` for preview deployments.

Preview deployments should be deleted as soon as testing is complete. They are only intended to last a short time and scale down to zero.

### Production

To deploy in production, your [Project](/api/project-configuration-overview.md) must not be a trial.

The `production` deployment type lets you deploy a Connector, which is already in production or is ready to be in your production environment. Only published Connectors can use the `production` deployment type.

`production` provides the highest scalability for optimal performance and stability of the Connector, with already warmed-up instances ready to manage the load at all times.

If you have not previously published your Connector to `production`, contact your Customer Success Manager or the [commercetools support team](https://support.commercetools.com/) for assistance.

## Related pages

- [Area overview page with navigation](/connect.md)
- [Previous page: Validation pipeline](/connect/validation-pipeline.md)
- [Next page: Certification](/connect/certification.md)
- [Search documentation and API specs](/search.md)