> For the complete documentation index, see [llms.txt](https://devs.snowdropsolutions.co.uk/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://devs.snowdropsolutions.co.uk/basic-concepts.md).

# Basic Concepts

- [List request](https://devs.snowdropsolutions.co.uk/basic-concepts/list-request.md): Sending multiple transactions in one request
- [Restrictive vs Extended](https://devs.snowdropsolutions.co.uk/basic-concepts/restrictive-vs-extended.md): Exploring MRS request types.
- [Merchant Category Codes](https://devs.snowdropsolutions.co.uk/basic-concepts/merchant-category-codes.md)