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

# Architecture Overview

> How Chroma is structured across local, single-node, and distributed deployments.

Chroma is designed with a modular architecture that prioritizes performance and ease of use. It scales from local development to large-scale production while exposing a consistent API across deployment modes.

Chroma delegates as much as possible to durable, well-understood subsystems such as SQLite and cloud object storage, so the core system can stay focused on data management and information retrieval.

## Deployment Modes

Chroma supports three deployment modes:

* **Local**: an embedded library for prototyping and experimentation.
* **Single-Node**: a single server for small to medium workloads, typically fewer than 10 million records across a handful of collections.
* **Distributed**: a scalable multi-service deployment for large production workloads and millions of collections.

You can use [Chroma Cloud](https://www.trychroma.com/signup?utm_source=docs-architecture), which is the managed offering of distributed Chroma.

<Card title="Distributed Architecture" href="/reference/architecture/distributed">
  Learn how Chroma scales out with independent services, object storage, SSD caches, and a shared system database.
</Card>

## Chroma Data Model

Chroma's data model balances simplicity, flexibility, and scalability. It introduces a few core abstractions: **tenants**, **databases**, and **collections**.

### Collections

A **collection** is the fundamental unit of storage and querying in Chroma. Each collection contains items with:

* A unique ID
* An embedding vector
* Optional metadata
* A document

Collections are independently indexed and optimized for vector similarity, full-text search, and metadata filtering.

### Databases

Collections are grouped into **databases**, which provide a logical namespace for environments or applications.

Each database contains multiple collections, and each collection name must be unique within that database.

### Tenants

At the top level of the model is the **tenant**, which represents a user, team, or account.

Tenants provide complete isolation. Access control, quota enforcement, and billing are all scoped to the tenant level.