# Build or integrate an app with SLB cloud APIs

Developers can build custom applications by integrating with the cloud APIs offered by the SLB Digital Platform.

These custom apps can be:

- **Custom domain workflows** built using data APIs and integration with various simulators.
- **Add-ons or extensions** to extend/customize workflows of platform applications.
- **AI applications** developed using the AI Workspace and integration with cloud APIs.


## Steps to build an app using SLB cloud APIs

1. **Register your app**
Begin by registering your app with the SLB Digital Platform.
2. **Choose your development framework**
Developers can use their preferred development frameworks (such as Python, Angular, etc.) to build custom apps.
3. **Implement authentication and obtain access token**
Use the credentials obtained during registration to implement an authentication pattern to obtain an access token. Refer to [Authentication Scenarios](#authentication-scenarios) for details.
4. **Call SLB cloud APIs**
Use this access token to call various cloud APIs.


## Authentication scenarios

### 1. Apps acting on behalf of a user

If your app needs to perform actions and call APIs on behalf of a user, use a **user access token**. This approach limits the app’s capabilities to the permissions granted to both the app and the user. The user must authorize the app before it can act.
See: [Authenticating an App on Behalf of a User](/guides/cloud-apis/create-first-app/authenticating-on-behalf-user)

### 2. Apps acting on their own behalf

This pattern is for apps that need to access APIs independently of a user. It involves non-interactive, system-to-system or app-to-app communication.
See: [Authenticating as an App](/guides/cloud-apis/create-first-app/authenticating-as-app)

## Recommended further reading

- [User context](/solutions/ccm/tutorial/user-context-service) in SLB Digital Platform.
- [Secret management](/solutions/sauth/tutorial/secret-management-service) in the SLB Digital Platform.
- [API maturity](/guides/cloud-apis/references/api-lifecycle) of cloud APIs.
- Refer to the tutorials of various solutions (such as [FDPlan](/solutions/fdplan/tutorial/about), [DrillPlan](/solutions/drillplan/docs/tutorials/tutorial), [MPDF](/solutions/core-service/tutorial/osdu-core-services-about), etc.) to learn more about their extensibility and how to integrate with APIs offered by these solutions into your application.