# API Reference

**Interfaces for querying your Lynk semantic layer.**

This section documents the query interfaces exposed by Lynk — how to write queries against your semantic layer and how to call Lynk programmatically.

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## What's in this section

| Page                                       | What it covers                                                                                                                                 |
| ------------------------------------------ | ---------------------------------------------------------------------------------------------------------------------------------------------- |
| [Lynk SQL](/api-reference/api/lynk-sql.md) | The SQL dialect the agent uses internally and you use when writing evaluation test cases — `entity()`, `metric()`, joins, supported statements |
| [REST API](/api-reference/api/rest-api.md) | HTTP endpoints for querying the semantic layer programmatically                                                                                |

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**Where to go next:**

* Need to understand how entities and metrics are defined? → [Concepts](/concepts/concepts.md)
* Writing evaluation test cases that use Lynk SQL? → [Evaluations YAML](/file-types-reference/file-types/evaluations-yaml.md)


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# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.getlynk.ai/api-reference/api.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.