# Technical Documentation: Respect/Validation

> ℹ️ **Provenance:** Hybrid Fusion: `Respect/Validation` (README + 2 In-Tree Chapters) · [CodeWiki Reference](https://codewiki.google/github.com/Respect/Validation) · Recency: Active (< 180 days)

## 1. Project Overview & Quickstart (Respect/Validation)

# Respect\Validation

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[](https://codecov.io/gh/Respect/Validation)
[](https://packagist.org/packages/respect/validation)
[](https://packagist.org/packages/respect/validation)
[](https://packagist.org/packages/respect/validation)

The most awesome validation engine ever created for PHP.

- Complex validation made simple: `v::numericVal()->positive()->between(1, 255)->isValid($input)`.
- Advanced [exception handling](docs/handling-exceptions.md).
- [More than 150](docs/validators.md) (fully tested) validators.

Learn More:

* [Documentation](https://respect-validation.readthedocs.io)
* [How to contribute](CONTRIBUTING.md)

## 2. In-Tree Documentation Chapters (Respect/Validation)

## File: docs/index.md

# Overview

The most awesome validation engine ever created for PHP.

- Complex validation made simple: `v::numericVal()->positive()->between(1, 255)->isValid($input)`.
- Advanced [exception handling](handling-exceptions.md).
- [More than 150](validators.md) (fully tested) validators.

---

## File: docs/getting-started.md

# Getting Started

Welcome to Respect\Validation!

This guide will help you get up and running with the library quickly.

## Installation

To install Respect\Validation, use [Composer](http://getcomposer.org):

```shell
composer require respect/validation:^3.0
```

Ensure you have PHP 8.5 or above installed.

## Basic usage

The `ValidatorBuilder` (aliased as `v` for convenience) provides a fluent interface for building validators and running them.

### Validating using exceptions

The `assert()` method throws an exception when validation fails. Handle these exceptions with `try/catch` for robust error handling:

```php
try {
    v::intType()->assert($input);
} catch (Throwable $exception) {
    echo 'Validation failed: ' . $exception->getMessage();
}
```

### Validating without exceptions

The `validate()` method returns a `ResultQuery` object that allows you to inspect and display validation results:

```php
$result = v::intType()->validate($input);
if ($result->hasFailed()) {
    echo 'Validation failed: ' . $result->getMessage();
}
```

### Validating using booleans

Use the `isValid()` method to check if your input meets specific validation criteria:

```php
if (!v::intType()->isValid($input)) {
    echo 'The input you gave me is not an integer';
}
```

## Key Features

### Complex validation

Combine multiple validators for complex validation rules:

```php
v::numericVal()->positive()->between(1, 255)->assert($input);
```

### Custom error messages

Define your own error messages when validation fails:

```php
v::between(1, 256)->assert($input, '{{subject}} is not what I was expecting');
```

### Custom exceptions

Throw your own exceptions when the validation fails:

```php
try {
    v::between(1, 256)->assert($input, new DomainException('Not within the expected range'));
} catch (DomainException $exception) {
    echo 'Custom exception caught: ' . $exception->getMessage();
}
```

### Reusing validators

Create validators once and reuse them across multiple inputs:

```php
$validator = v::alnum()->lowercase();

$validator->assert('respect');
$validator->assert('validation');
```

## Next steps

- Explore the [Feature Guide](feature-guide.md) for more advanced usage.
- Check out the [List of Validators by Category](validators.md) for a comprehensive list of available validators.

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