---
title: Form validation
slug: data-platform/connect-platform/ocpcoreconcepts-form-validation
docTags: 
createdAt: 2026-08-05T20:06:38.318Z
---

There are three types of form validation: [required](docId\:Vw673kZaCM3G5I0w5LFx6), [regular expression (regex) matcher](docId\:Vw673kZaCM3G5I0w5LFx6), and [predicate evaluation](docId\:Vw673kZaCM3G5I0w5LFx6).

## Required

Required is a first-class property on all form elements. To mark a field as required, set `required` to `true`. Your app then automatically validates the field to ensure it is not blank when users submit your app's settings form. For example:

```yaml
elements:
- type: text
  key: login
  label: Login
  help: Your login details for SampleIntegration
  required: true
```

## Regex matcher

A regex matcher tests if the user input value matches a regex. If not, the error message is displayed when the user tries to submit the form. The string a user enters must be a value you can pass into new `RegExp()` in standard JavaScript. For example:

```yaml
validations:
- regex: "^\\w+$"
  message: Only letters, numbers, and underscores are allowed.
```

## Predicates

If you want to use logic to validate user input based on values of other fields in the form, use a predicate instead of a single regex matcher. For example:

```yaml
validations:
- predicate:
  operation: all
  comparators:
  - key: auth.username
    empty: false
  - key: auth.password
    empty: false
  message: Username and Password are both required if you are authenticating by username.
```

You can also use booleans to permanently set a value to `true` or `false`. This is useful if you want to permanently disable something (until a later update, for example, `disabled: true`).

## Advanced predicates

For more advanced logic, you can use a predicate to generate a logic tree. This is especially useful when you want to check values in multiple fields.

A predicate contains an operation (`all`, `any`, `none`) which translates directly to boolean logic (`and`, `or`, `not`) and a list of comparators (`Comparator`, `ListComparator`, or another `Predicate`). See the examples below:

Enable the submit button after the user completes both the user and password fields:

```yaml
disabled:
  operation: all
  comparators:
  - key: auth.user
    empty: false
  - key: auth.password
    empty: false
```

Display a form if a user selects one or more lists or if the user toggles the auto option on:

```yaml
visible:
  operation: any
  comparators:
  - key: sync.auto
    equals: true
  - key: sync.lists
    empty: false
```

Display a message stating both username and password are required if the user tries to submit the form without completing both:

```yaml
validations:
- predicate:
  operation: all
  comparators:
  - key: auth.username
    empty: false
  - key: auth.password
    empty: false
  message: Username and Password are both required if you are authenticating by username.
```

### Comparator

A `Comparator` lets you compare using a regex, equality, or to test if a value is empty. See the following examples:

Hide unless `auth.email` is a valid email:

```yaml
visible:
  key: auth.email
  regex:"/[^@]+@[^\\.]+\\..{2,}/"
```

Show when `sync.enabled` is toggled on:

```yaml
visible:
  key: sync.enabled
  equals: true
```

Disable if `auth.login` is empty/blank:

```yaml
disabled:
  key: auth.login
  empty: true
```

### ListComparator

The `ListComparator` has the same functionality as a `Comparator`, but it is used when comparing to the value of a `multi-select` option, which produces an array of values. Because you need to compare against multiple values, it includes an `operation` option so you can test using `and` (`all`), `or` (`any`), or `not` (`none`) logic. See the following examples:

Assume there is a multi-select option called `lists` on the `sync` section. Disable a control if all `sync.lists` are prefixed with `default_`:

```yaml
disabled:
  key: sync.lists
  operation: all
  regex: "/^default_/"
```

Display a control if the user included the default list:

```yaml
visible:
  key: sync.lists
  operation: any
  equals: default
```

Disable a control unless the user included the default list:

```yaml
disabled:
  key: sync.lists
  operation: none
  equal: default
```