# Define your form

Creating a form in Formisch starts with defining a Valibot schema. The schema serves as the blueprint for your form, outlining the structure, data types, and validation rules for each field.

## Schema definition

Formisch is a schema-first form library built on top of [Valibot](https://valibot.dev/). When you create a form with <Link href="/solid/api/createForm/">`createForm`</Link>, TypeScript types are automatically inferred from your schema, giving you full autocompletion and type safety throughout your form without needing to write any manual type definitions.

### Example schema

The following schema defines a form with two required string fields. The `email` field must be a valid email format, and the `password` field must be at least 8 characters long. Each validation includes custom error messages that will be displayed when validation fails.

> For more complex schema examples, check out the schemas of our <Link href="/playground/">playground</Link>.

```ts
import * as v from 'valibot';

const LoginSchema = v.object({
  email: v.pipe(
    v.string('Please enter your email.'),
    v.nonEmpty('Please enter your email.'),
    v.email('The email address is badly formatted.')
  ),
  password: v.pipe(
    v.string('Please enter your password.'),
    v.nonEmpty('Please enter your password.'),
    v.minLength(8, 'Your password must have 8 characters or more.')
  ),
});
```

## Schema validation

Your schema definition should reflect exactly the data you expect when submitting the form. For example, if the value of a field is optional and will only be submitted in certain cases, your schema should reflect this information by using `v.optional(…)`.

```ts
import * as v from 'valibot';

const ProfileSchema = v.object({
  name: v.pipe(v.string(), v.nonEmpty()),
  bio: v.optional(v.string()), // <- Optional field
});
```

Formisch validates your form values against the schema before submission, ensuring that your form can only be submitted if it matches your schema definition.

## Next steps

Now that you understand how to define your form schema, continue to the <Link href="/solid/guides/create-your-form/">create your form</Link> guide to learn how to initialize your form with <Link href="/solid/api/createForm/">`createForm`</Link>.