> ## Documentation Index
> Fetch the complete documentation index at: https://knowledge-base-starter-mintlify-85d166f9.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Data models

> Core entities, their key fields, relationships, and where they live.

This page documents the primary domain entities. For schema definitions, see the migration files in the Core API repo.

## Core entities

### User

Represents an authenticated person. One user can belong to multiple organizations.

| Field           | Type      | Description            |
| --------------- | --------- | ---------------------- |
| `id`            | UUID      | Primary key            |
| `email`         | string    | Unique, used for login |
| `created_at`    | timestamp | Account creation time  |
| `last_login_at` | timestamp | Last successful auth   |

### Organization

A company or team account. The primary billing and access control boundary.

| Field      | Type      | Description                 |
| ---------- | --------- | --------------------------- |
| `id`       | UUID      | Primary key                 |
| `name`     | string    | Display name                |
| `plan`     | enum      | `free`, `pro`, `enterprise` |
| `owner_id` | FK → User | Billing owner               |

### Membership

Junction table linking users to organizations with a role.

| Field       | Type              | Description                |
| ----------- | ----------------- | -------------------------- |
| `user_id`   | FK → User         |                            |
| `org_id`    | FK → Organization |                            |
| `role`      | enum              | `owner`, `admin`, `member` |
| `joined_at` | timestamp         |                            |

## Relationships

```mermaid theme={null}
graph LR
    User --- Membership
    Organization --- Membership
    User --- Organization
```

A user can be a member of many organizations. An organization can have many members. The `Membership` table holds the role for each pair.

## Data storage

| Data type       | Storage                    | Notes                           |
| --------------- | -------------------------- | ------------------------------- |
| Relational data | Postgres                   | Primary store, via Core API     |
| Sessions        | Redis                      | TTL-based, auto-expire          |
| File uploads    | S3-compatible object store | Referenced by URL in Postgres   |
| Search index    | \[Search service]          | Synced from Postgres via worker |

## Sensitive fields

The following fields are encrypted at rest and must never appear in logs:

* `User.password_hash`
* Payment method tokens (stored in your payment processor, referenced by ID only)
* Any field containing PII in audit logs

If you're adding a new field that contains PII or credentials, flag it in your PR for security review.