# Developer Tools
source: https://developer.mastercard.com/eligibility-api/documentation/developer-tools/index.md

* [Postman Collection](https://developer.mastercard.com/eligibility-api/documentation/developer-tools/postman-collection/index.md)
* [Insomnia Collection](https://developer.mastercard.com/eligibility-api/documentation/developer-tools/insomnia-collection/index.md)
* [Widget Integration](https://developer.mastercard.com/eligibility-api/documentation/tutorials-and-guides/widget-tutorial/widget-integration/index.md)
* [Widget Customization](https://developer.mastercard.com/eligibility-api/documentation/tutorials-and-guides/widget-tutorial/widget-customization/index.md)

## Next Steps {#next-steps}

* Import the [Postman Collection](https://developer.mastercard.com/eligibility-api/documentation/developer-tools/postman-collection/index.md) or [Insomnia Collection](https://developer.mastercard.com/eligibility-api/documentation/developer-tools/insomnia-collection/index.md) to send your first signed Sandbox request.
* Review the [Testing](https://developer.mastercard.com/eligibility-api/documentation/testing/index.md) guide for sample test data to use with these tools.