# Types and formats

[Open in the interactive reference](https://docs.api.lensing.ai/?op=guide%3Atypes)

### Decimals

Decimal values are strings, such as `"1234.56"`, so that no digit is lost in a JSON parser. Read them into a decimal type, never a float, and compare them as numbers rather than as text. Send them as strings too: a JSON number is accepted, but your serializer may already have rounded it.

### Money

A monetary amount comes with an ISO 4217 currency code, either beside the amount, in an object with `amount` and `currency`, or on the document the amount belongs to. The field's description says which.

### Dates and times

| Type | In a response | In a request |
| --- | --- | --- |
| Date | `2026-01-15` | The same. |
| Time of day | `09:30:00.000` | Also `09:30:00` or `09:30`. |
| Date and time, no time zone | `2026-01-15T09:30:00.000` | Seconds required, milliseconds optional. |
| Instant, in UTC | `2026-01-15T09:30:00.000Z` | Fractional seconds and the `Z` required. |

A date and time without a time zone is a wall-clock time: when something happens locally, wherever that is. An instant is an exact moment.

Send an instant in UTC, with fractional seconds and a trailing `Z`, as in `2026-01-15T09:30:00.000Z`. A value without fractional seconds, such as `2026-01-15T09:30:00Z`, is refused with `400`. A value that gives an offset instead of `Z`, such as `2026-01-15T11:30:00.000+02:00`, is also refused.

Responses always include milliseconds, whatever the request sent, so compare dates and times as values, not as strings. The OpenAPI document gives both date-and-time types the format `date-time`; check a field's description to see whether it is an instant.

### Absent, null, and omitted

In a request, omitting a field means “leave it unchanged”, and sending `null` means “clear it”. `null` is accepted only on fields marked nullable, and refused with `400` on any other.

In a response, a field with no value is left out rather than sent as `null`, in a collection's records as well as in a single record. A field you did not select with `fields=` is left out too. Read a missing field as having no value, not as an error.

## Examples

**Values in a response**

```json
{
  "amount": "1234.56",
  "currency": "EUR",
  "releaseDate": "2026-01-15",
  "availableFrom": "09:30:00.000",
  "lastRestockedAt": "2026-01-15T09:30:00.000",
  "createdAt": "2026-01-15T09:30:00.000Z"
}
```