* [Reference](reference/feast-cli-commands.md) contains detailed API and design documents.

* [Contributing](contributing/contributing.md) contains resources for anyone who wants to contribute to Feast.


* **Create Batch Features:** ELT/ETL systems like Spark and SQL are used to transform data in the batch store.

* **Feast Apply:** The user \(or CI\) publishes versioned controlled feature definitions using `feast apply`. This CLI command updates infrastructure and persists definitions in the object store registry.

* **Prediction:** A backend system makes a request for a prediction from the model serving service.

* **Get Online Features:** The model serving service makes a request to the Feast Online Serving service for online features using a Feast SDK.

A complete Feast deployment contains the following components:

Projects provide complete isolation of feature stores at the infrastructure level. This is accomplished through resource namespacing, e.g., prefixing table names with the associated project. Each project should be considered a completely separate universe of entities and features. It is not possible to retrieve features from multiple projects in a single request. We recommend having a single feature store and a single project per environment \(`dev`, `staging`, `prod`\).

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Projects are currently being supported for backward compatibility reasons. Projects may change in the future as we simplify the Feast API.

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