# Integration and Testing
source: https://developer.mastercard.com/issuer-enrollment/documentation/integration-and-testing/index.md

## Ready to Begin? {#ready-to-begin}

Tip: We recommend that you begin testing in the sandbox environment.

Once you have onboarded to Mastercard Click to Pay using our [onboarding tutorial](https://developer.mastercard.com/issuer-enrollment/tutorial/issuer-onboarding-click2pay/index.md), generated [API keys](https://developer.mastercard.com/issuer-enrollment/tutorial/key-management-click2pay/index.md), and reviewed the [use cases](https://developer.mastercard.com/issuer-enrollment/documentation/use-cases/auto-enrollment/index.md), you can start testing.

### Methods of Testing Sandbox/Production {#methods-of-testing-sandboxproduction-br}

#### 1. Postman {#1-postman}

> * [Postman](https://www.postman.com/) is an API client that allows developers to test your API's calls in sandbox and production environments without writing any code. [Postman Collections](https://www.postman.com/collection/) makes sharing pre-formed API requests with partners extremely easy, and permits partners to run individual API requests or those within a folder or the entire collection.
> * For detailed steps, follow our [Postman Collections Page](https://developer.mastercard.com/issuer-enrollment/documentation/postman-collection/index.md).

#### 2. Insomnia {#2-insomnia}

> * [Insomnia](https://insomnia.rest/) is an open-source API client that developers use to quickly and easily send HTTP requests to Mastercard APIs. Mastercard API team has developed an [Insomnia Plugin](https://github.com/Mastercard/insomnia-plugin-mastercard) for handling API authentication.
> * Follow our [Insomnia Collection Page](https://developer.mastercard.com/issuer-enrollment/documentation/insomnia-collection/index.md) to learn how to test the Issuer Enrollment APIs using Insomnia.

### Next Steps {#next-steps-br}

While you begin making API calls using our [Postman](https://developer.mastercard.com/issuer-enrollment/documentation/postman-collection/index.md) or [Insomnia](https://developer.mastercard.com/issuer-enrollment/documentation/insomnia-collection/index.md) collections, head over to our [Codes and Formats](https://developer.mastercard.com/issuer-enrollment/documentation/code-and-formats/index.md) section to learn about the details of all the error codes.

## Testing {#testing}

Start by following our:

### Test Scenarios {#test-scenarios}

Refer to our [Auto Enrollment](https://developer.mastercard.com/issuer-enrollment/documentation/testing/auto-enrollment/index.md) and [Passkeys](https://developer.mastercard.com/issuer-enrollment/documentation/testing/passkeys/index.md) sections for different test cases.