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

# Schemas

> Define and manage event schemas

Every event name you ingest must have a registered schema. The schema defines the expected fields and their types -- events are validated against it at ingest time.

<Note>
  Schemas are app-scoped. Use `client.forApp('my-app').schemas` to access them.
</Note>

## List schemas

```typescript theme={null}
const schemas = await appRes.schemas.list();
```

## Get by event name

```typescript theme={null}
const schema = await appRes.schemas.getByEventName('order.placed');
```

## Create a schema

```typescript theme={null}
const schema = await appRes.schemas.create({
  eventName: 'order.placed',
  description: 'Emitted when a checkout completes',
  fields: [
    {
      id: 'fld-order-id',
      name: 'orderId',
      type: 'string',
      required: true,
      validation: { min: 1, max: 128 },
    },
    {
      id: 'fld-amount',
      name: 'amountCents',
      type: 'number',
      required: true,
    },
    {
      id: 'fld-currency',
      name: 'currency',
      type: 'enum',
      required: true,
      enumValues: ['USD', 'EUR', 'GBP'],
    },
    {
      id: 'fld-items',
      name: 'itemCount',
      type: 'number',
      required: false,
      defaultValue: 1,
    },
  ],
  metadataFields: [
    {
      id: 'meta-env',
      name: 'environment',
      type: 'string',
      description: 'e.g. production, staging',
    },
  ],
});
```

## Update a schema

```typescript theme={null}
const updated = await appRes.schemas.update(schema.id, {
  description: 'Updated description',
  fields: [...],
});
```

## Field types

| Type      | Description          | Validation options                       |
| --------- | -------------------- | ---------------------------------------- |
| `string`  | Text value           | `min`, `max` (length), `pattern` (regex) |
| `number`  | Numeric value        | `min`, `max`                             |
| `boolean` | `true` or `false`    | --                                       |
| `date`    | ISO-8601 date string | --                                       |
| `enum`    | Fixed set of strings | Provide `enumValues` array               |
| `object`  | Nested JSON object   | --                                       |

## Schema field interface

```typescript theme={null}
interface SchemaField {
  id: string;
  name: string;
  type: 'string' | 'number' | 'boolean' | 'date' | 'enum' | 'object';
  required: boolean;
  defaultValue?: unknown;
  description?: string;
  enumValues?: string[];
  validation?: {
    min?: number;
    max?: number;
    pattern?: string;
  };
}
```

<Tip>
  You can also manage schemas as code using the [Vela CLI](/cli/overview) -- define schemas in JSON files and push them with `vela push`.
</Tip>