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

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

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

Once you have created a project on Mastercard Developers, generated sandbox credentials and received approvals, you can start testing.

### Base URLs for testing {#base-urls-for-testing}

* Sandbox
* Production

```Sandbox
https://sandbox.api.mastercard.com/loyalty/offers
https://sandbox.api.mastercard.com/loyalty/offers/presentment
```

```Production
https://api.mastercard.com/loyalty/offers
https://api.mastercard.com/loyalty/offers/presentment
```

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

### 1. Reference application {#1-reference-application}

Our Spring Boot reference application acts as an API client and allows you to integrate different operations.

For detailed steps, follow our [Reference Application](https://developer.mastercard.com/presentment/documentation/reference-application/index.md) page.

### 2. Postman {#2-postman}

[Postman Collections](https://www.postman.com/collection/) is an API client that allows developers to test API calls in sandbox and production environments without writing any code. This makes sharing pre-formed API requests with partners easy, and permits partners to run individual API requests or those within a folder or the entire collection.

For detailed steps, follow the [Postman tutorial](https://developer.mastercard.com/platform/tutorial/use-postman-for-mastercard-apis/).

### 3. Insomnia {#3-insomnia}

[Insomnia](https://insomnia.rest/) is an open-source API client that developers use to quickly and easily send REST requests to Mastercard APIs. Refer to the [Insomnia Plugin](https://github.com/Mastercard/insomnia-plugin-mastercard) for handling API authentication.

For detailed steps, follow:

* [Insomnia tutorial for OAuth 1.0 authentication](https://developer.mastercard.com/platform/tutorial/use-insomnia-rest-client-for-mastercard-apis/)
* [Insomnia tutorial for User Account Administration OAuth 2.0 authentication](https://developer.mastercard.com/presentment/tutorial/user-account-admin-api-authentication-and-first-call/index.md)
* [Insomnia tutorial for Offers for Publishers API OAuth 2.0 authentication](https://developer.mastercard.com/presentment/tutorial/offers-for-publishers-api-authentication-and-first-call/index.md)

##### Download our Insomnia Collection {#download-our-insomnia-collection}

* [Offers API Insomnia Collection](https://static.developer.mastercard.com/content/presentment/uploads/offers_API_insomnia_collection.zip)
* [User Account Administration Insomnia Collection](https://static.developer.mastercard.com/content/presentment/uploads/UserAccountAdministrationAPI_Collection_Sandbox.zip)

##### Import and configure the Insomnia Collection {#import-and-configure-the-insomnia-collection}

Import the Insomnia collection file directly into Insomnia. After importing, update the environment configuration with your client‑specific details.

Configure the following fields in the environment:

* consumerKey
* keyAlias
* keystoreP12Path
* keystorePassword
* encryptionCertificate
* keyStore
* keyStoreAlias
* x-openapi-clientid
* public-key-fingerprint
  * This value corresponds to the key from the Mastercard Encryption Key section.

Note: Select OAuth 1.0a only if you have not upgraded to OAuth 2.0.

![alt text](https://static.developer.mastercard.com/content/presentment/uploads/environments.png "collection environments")

## Next steps {#next-steps}

* When you are ready to use the API, refer to the [Reference Application](https://developer.mastercard.com/presentment/documentation/reference-application/index.md) section for information on connecting to Offers for Publishers.
* To learn more about any error codes you receive, refer to [Code and Formats](https://developer.mastercard.com/presentment/documentation/code-and-formats/index.md).