Fluent API overview

Fynix rules are configured through an immutable fluent API. Start with a rule from the Rule facade, then chain constraints that describe the value or object field you want to validate.

use Fynix\Rule;

$email = Rule::email('email')
    ->required()
    ->max(180);

$error = $email->validate('not-an-email');

Each configuration method returns a new rule. The original rule is unchanged, which makes it safe to reuse a base definition:

$baseName = Rule::string('name')->min(2)->max(80);
$requiredName = $baseName->required();
$optionalName = $baseName->optional();

Choose the binding style

Use a standalone rule when you already have a scalar value:

$error = Rule::string('firstName')
    ->min(2)
    ->validate('A');

Use Rule::for($object) when the value belongs to an object instance:

$error = Rule::for($user)
    ->string('firstName')
    ->min(2)
    ->validate();

Use Rule::on(User::class) or a RuleSet when defining reusable class-scoped rules:

$rules = [
    Rule::on(User::class)->string('firstName')->min(2),
    Rule::on(User::class)->email('email')->max(180),
];

Use ValidationHandler::validate() when running several rules against a complete object. The handler calls the rules internally; do not add ->validate() inside its rules array.

Method groups

Group	Methods	Use for
Presentation	label()	Human-readable error labels
Presence	required(), optional()	Empty and missing values
Bounds	min(), max(), length()	Length, numeric, or collection limits
Value sets	in(), notIn()	Allow-lists and deny-lists
Cross-field	sameAs(), differentFrom()	Comparing fields on one object
Conditional presence	requiredIf(), requiredUnless()	Requiring fields based on another field or closure
Conditional prohibition	prohibitedIf(), prohibitedUnless()	Rejecting fields based on a field or closure
Conditional execution	when()	Running a complete validator only when a closure matches
Pipeline controls	genericValidation(), withoutGenericValidation()	Shared validation behavior
Execution	validate(), validateAll()	Running one rule

Every method is documented in detail in this section. See Rules, RuleSet, and registry for construction and registration, or begin with label().

Conditional methods accept either a field/value pair or a closure receiving the object being validated. sameAs() and differentFrom() accept closures that return the comparison value. Use when() to conditionally skip the entire validator pipeline.