# Concepts

- [Staging Environment](/plum/developer-resources/overview-of-reward_api/concepts/staging-environment.md): This section walks you through the process of testing our different API in a staging environment.
- [Catalog](/plum/developer-resources/overview-of-reward_api/concepts/catalog-refresh.md): Xoxoday offers a vast collection of vouchers that can be ordered via the Rewards API.
- [Error Handling](/plum/developer-resources/overview-of-reward_api/concepts/errors.md): Xoxoday Plum Pro API uses conventional HTTP status codes to indicate success or failure. Responses with a status code starting with 4xx or 5xx can be considered as failed. The API returns errors in JS
- [Standard HTTP status code summary](/plum/developer-resources/overview-of-reward_api/concepts/errors/standard-http-status-code-summary.md)
- [Errors related to API](/plum/developer-resources/overview-of-reward_api/concepts/errors/errors-related-to-api.md)
- [Exchange Rates](/plum/developer-resources/overview-of-reward_api/concepts/exchange-rates-1.md): This section deals with exchange rates during currency conversion.