> 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/ios-sdk/reference/validation.md).

# Validation limits

The SDK checks these inputs before it sends a request. Most failures throw a `JanuaryError` with the `.validation` category; portion inputs throw `FoodPortionError`, and the scanner settings are clamped instead. The January API can apply more rules of its own.

| Input                                              | Accepted value                                                                            |
| -------------------------------------------------- | ----------------------------------------------------------------------------------------- |
| Autocomplete query                                 | At most 64 characters                                                                     |
| Autocomplete limit                                 | Integer from 1 through 20                                                                 |
| Food search query                                  | 1 through 256 characters                                                                  |
| Food search limit                                  | 1 through 50                                                                              |
| Food search offset                                 | 0 or more                                                                                 |
| Barcode                                            | 6 through 14 ASCII digits                                                                 |
| Natural-language meal                              | 1 through 512 characters                                                                  |
| Restaurant/menu query                              | 1 through 256 characters                                                                  |
| Latitude                                           | −90 through 90                                                                            |
| Longitude                                          | −180 through 180                                                                          |
| Restaurant radius                                  | 1 through 50,000 meters                                                                   |
| Restaurant limit                                   | Integer from 1 through 100                                                                |
| Food-log `timestampUTC`                            | ISO 8601 date-time                                                                        |
| Food-log update                                    | At least one of `foods`, `timestampUTC`, `name`                                           |
| Water amount                                       | 1 through 811.5 fl oz, 0.1 through 101.4 cup, or 30 through 24,000 ml                     |
| Weight-log weight                                  | 10 through 1,000 lb, or 4.5 through 453.6 kg                                              |
| Water and weight `consumedAtUTC` / `measuredAtUTC` | ISO 8601 date-time                                                                        |
| Glucose profile `age`                              | Whole number of years                                                                     |
| Food analysis correction                           | Every detection carries its food ID, serving ID, serving quantity, and quantity           |
| CGM and historical-food timestamp                  | ISO 8601 date-time                                                                        |
| Provider token                                     | Not empty, with a finite `expiresIn` greater than 60 seconds (an `.authentication` error) |
| Portion quantity, in the serving's unit            | Finite, greater than 0, and no greater than 10,000                                        |
| Scanner maximum dimension                          | Clamped to at least 1 pixel                                                               |
| Scanner JPEG quality                               | Clamped to 0 through 1                                                                    |

## Typed units

Glucose profiles use explicit units:

```swift
let height = Height(value: 178, unit: .centimeters)
let weight = Weight(value: 80, unit: .kilograms)
```

Height takes inches or centimeters, and weight takes pounds or kilograms.

## Local portion errors

`FoodPortionError` distinguishes:

* `noServings`
* `servingNotFound`
* `invalidServing`
* `invalidQuantity`

Fetch the full food (`foods.get`) before computing a portion, so every serving is available.