> For the complete documentation index, see [llms.txt](https://docs.january.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.january.ai/client-sdks/react-native-sdk/reference/models-and-validation.md).

# Models and validation

All public request and response types are exported from `@januaryai/react-native`; import them with `import type`. Food categories are plain strings (`'generic'`, `'branded'`, `'recipe'`).

The SDK checks these inputs before it sends a request. Most checks run in the TypeScript wrapper and reject with an `Error` that has no `code`; the message names the field ([Errors](/client-sdks/react-native-sdk/reference/errors.md)).

| Input                                  | Validation                                                                 |
| -------------------------------------- | -------------------------------------------------------------------------- |
| `endUserId`                            | Required and non-empty                                                     |
| Food query, food ID, barcode, log ID   | Required and non-empty                                                     |
| Autocomplete limit                     | Integer from 1 through 20 (default 8)                                      |
| Search limit                           | Integer from 1 through 50 (default 10)                                     |
| Restaurant, menu-item, and menu limits | Integer from 1 through 100                                                 |
| Restaurant latitude                    | -90 through 90                                                             |
| Restaurant longitude                   | -180 through 180                                                           |
| Restaurant radius                      | 1 through 50,000 meters                                                    |
| Menu offset                            | Non-negative integer                                                       |
| Food selections                        | At least one item with food ID, serving ID, and quantity greater than zero |
| Glucose start time                     | Required and non-empty                                                     |
| Food log update                        | At least one of `foods`, `timestampUTC`, or `name`                         |
| Water amount, weight                   | Positive value with a unit of `fl_oz`/`ml`/`cup` or `lb`/`kg`              |
| Food, water, and weight log ranges     | `start` and `end` required and non-empty                                   |

Response fields marked optional may be absent. Avoid non-null assertions in production UI, and provide fallbacks for names, images, nutrition, servings, impact levels, and response IDs.

## Units

| Type         | Values                                                                        |
| ------------ | ----------------------------------------------------------------------------- |
| `VolumeUnit` | `'fl_oz'` (fluid ounces), `'ml'` (milliliters), `'cup'` (a US cup of 8 fl oz) |
| `WeightUnit` | `'lb'` (pounds), `'kg'` (kilograms)                                           |

January enforces a range per unit; see [Accepted values](/client-sdks/react-native-sdk/guides/water-and-weight-logs.md#accepted-values). Responses may carry a unit newer than this SDK.