> For the complete documentation index, see [llms.txt](https://docs.snomed.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.snomed.org/snomed-ct-practical-guides/snomed-ct-postcoordination-guide/expressions-in-a-terminology-server/requirements.md).

# Requirements

A terminology server supporting postcoordination should support the general features of a SNOMED CT-enabled terminology server, and additionally, support the features required to manage and use postcoordinated expressions. This involves an expression repository to store the postcoordinated expressions, and a set of services to access, process and query the expressions in the same way as pre-coordinated SNOMED CT content. This section provides an overview of the general requirements of an expression repository and the associated services.

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