> ## Documentation Index
> Fetch the complete documentation index at: https://oxy.tech/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Airlayer

> The open-source in-process semantic engine at the core of the World Model

**Airlayer** is the in-process semantic engine at the **core of the
[World Model](/docs/guide/build/world-model)**. It compiles your `.view.yml` and
`.topic.yml` schemas into dialect-specific SQL — resolving joins from entity
definitions and protecting against fan-out — so a measure means the same thing
everywhere and no query is hand-written or hallucinated. It's built to be
embedded, scripted, or called by agents.

Everything the [World Model](/docs/guide/build/world-model) does — the
[semantic model](/docs/guide/build/semantic-model/simple-model), the
[metric tree](/docs/guide/build/world-model/metric-tree), the entity graph — is
compiled by Airlayer.

## What it does

* **Deterministic SQL.** Given the same request, Airlayer always emits the same
  SQL — there's no LLM in the compilation path, so results are reproducible.
* **Automatic joins.** Entity declarations tell Airlayer how views relate, so it
  builds the join path for you and guards against fan-out double-counting.
* **Dialect-aware.** The same definitions compile to BigQuery, Snowflake,
  Postgres, DuckDB, and more.
* **Embeddable.** Airlayer runs in-process as a library or CLI, so agents and
  apps can compile and run semantic queries without a separate service.

<Card title="airlayer on GitHub" icon="github" href="https://github.com/oxy-hq/airlayer">
  In-process semantic engine that compiles YAML schemas into dialect-specific
  SQL. Open source.
</Card>

## Next steps

<CardGroup cols={2}>
  <Card title="The semantic model" icon="cube" href="/docs/guide/build/semantic-model/simple-model">
    Define the views Airlayer compiles
  </Card>

  <Card title="The World Model" icon="globe" href="/docs/guide/build/world-model">
    What Airlayer's output powers
  </Card>
</CardGroup>