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

# Core concepts

> Learn about the basics of SID

## Capsules

Capsules are where data is stored – think of it like a mixture between a database and an S3 bucket.
Each one is assigned a unique ID like `irrotational-airfoil` and is hosted at: `https://irrotational-airfoil.sid.ai`.
Data can be added through the dashboard or programmatically with the API.

## Queries

A query is the primary way to acces information in a capsule.
They are designed to be easy for *LLMs to write*.
Every query has three parts:

* `query`: natural language query, like "What is the capital of France?"
* `wishlist`: desired metadata filters – they can be completely free-form and don't need to exist in the data
* `limit`: the maximum number of results to return

## API keys

API keys are used to authenticate requests to the API. You can create an API key in the [dashboard](https://dashboard.sid.ai).