# Proof type JSON format

[No-code proof types](/hypersync-sdk/sdk-006-proof-types) are stored in a package's `/json/proof` directory. There should be one `.json` file in this directory for each proof type that is visible to the Hypersync app user.

Each proof type file exposes a JSON object with these properties:

| Property | Required? | Description |
|  --- | --- | --- |
| `description` | Yes | This is the description of the proof type. |
| `criteria` | Yes | This is an array of criteria fields that are required by the proof type. |
| `proofSpec` | Yes | An object that specifies how the proof type should be rendered. |
| `overrides` | No | These are proof specs that override the base proof spec based on a particular condition. |


## criteria

The `criteria` property is an array of JSON objects. Each element in the array represents a criteria field that the user must specify when configuring the proof type. If a proof type does not require any criteria, the criteria property should be defined as an empty array.(i.e. []).

Each object in the array has two required properties: `name` and `page`:

| Property | Description |
|  --- | --- |
| `name` | This identifies the criteria field in the [criteria provider](/hypersync-sdk/sdk-007-criteria). |
| `page` | A zero-based index of the page on which the criterion should be shown. |


## proofSpec

The `proofSpec` property is a JSON object that specifies how the proof type should be rendered.

| Property | Required? | Description |
|  --- | --- | --- |
| `period` | Yes | Determines the default synchronization schedule. Acceptable values are `daily`, `weekly`, `monthly`, `quarterly`, and `yearly`. |
| `useVersioning` | Yes | Determines whether or not to use versioning by default. |
| `suggestedName` | Yes | Determines the suggested name for new Hypersyncs using this proof type. |
| `format` | Yes | The format of the fields on the page. Acceptable values are `tabular` (fields that are side by side) and `stacked` (fields stacked vertically) |
| `orientation` | Yes | For PDF proof types. This property determines the orientation of the generated PDF. Acceptable values are `portrait` and `landscape`. |
| `title` | Yes | Determines the text to be rendered at the top of the generated proof. |
| `subtitle` | Yes | Determines the text to be rendered below the title. |
| `dataSet` | Yes | Determines the name of the dataset to which the proof type is bound. |
| `dataSetParams` | No | The parameters provided to the data source when retrieving the dataset. |
| `noResultsMessage` | No | Determines the text to be rendered if no items are found in the dataset. |
| `fields` | Yes | An array of fields to include with the generated proof. |
| `webPageUrl` | No | The URL shown at the bottom of the generated proof. |
| `autoLayout` | No | Determines if the fields within the specification are automatically laid out. Acceptable values are `true` and `false`. The default value is `false`. |


## overrides

The `overrides` property is optional and allows you to define alternative proof specs that replace the default proof spec under certain conditions.

For example, if you have a criteria field that lets the user select a group by name — and that control includes an “All Groups” option — you can use an override to change the layout of the generated proof when the user selects “All Groups".

When specified, the `overrides` property must be an array of objects. Each object must include two properties:

- `condition` — Defines when the override should apply.
- `proofSpec` — Specifies the proof spec to use when the condition is met.


## Example


```
{
  "description": "{{messages.PROOF_TYPE_USER_LIST}}",
  "criteria": [{ "name": "group", "page": 0 }],
  "proofSpec": {
    "period": "monthly",
    "useVersioning": true,
    "suggestedName": "{{messages.PROOF_TYPE_USER_LIST}}",
    "format": "tabular",
    "orientation": "landscape",
    "title": "{{messages.CONNECTOR_NAME}}",
    "subtitle": "{{messages.PROOF_TYPE_USER_LIST}}",
    "dataSet": "users",
    "dataSetParams": {
      "group": "{{criteria.group}}"
    },
    "noResultsMessage": "{{messages.NO_USERS}}",
    "fields": [
      {
        "property": "firstName",
        "label": "{{messages.LABEL_FIRST_NAME}}",
        "width": "400px",
        "type": "text"
      },
      {
        "property": "lastName",
        "label": "{{messages.LABEL_LAST_NAME}}",
        "width": "400px",
        "type": "text"
      },
      {
        "property": "email",
        "label": "{{messages.LABEL_EMAIL_ADDRESS}}",
        "width": "200px",
        "type": "text"
      },
      {
        "property": "status",
        "label": "{{messages.LABEL_STATUS}}",
        "width": "200px",
        "type": "text"
      }
    ],
    "webPageUrl": "https://myservice.com/users"
  }
}
```