Email Validator for PHP

A small, framework‑agnostic PHP library to validate email addresses with.

Separates format validity from deliverability, supports domain typo suggestions, and lets you plug in custom providers for lists and DNS. File/INI list handling is offered via a small adapter.

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Features

• Format-only validity (valid) — syntax & RFC length checks plus basic domain shape.
• Deliverability prediction (sendable) — DNS: domain existence + MX records (via pluggable resolver).
• Domain suggestions with typo‑distance scoring (Levenshtein or Damerau–Levenshtein)
• Pluggable list checks — allow/deny by domain or full address via a ListProvider.
• Clear result model — typed getters for PHP and compact JSON for APIs.
• A clean, typed ValidationResult DTO and an optional OpenAPI spec for a tiny REST endpoint
• PHP 8.1+, Psalm-typed, PHPUnit-tested, PSR-12 styled.

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Installation

composer require dartcafe/email-validator

Requires PHP 8.1+. For Internationalized Domain Names (IDN) support, enable ext-intl (recommended).

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Quick start

<?php

use Dartcafe\EmailValidator\EmailValidator;
use Dartcafe\EmailValidator\Suggestion\TextDomainSuggestionProvider;

// Create a validator with default providers
$validator = new EmailValidator(
    suggestions: TextDomainSuggestionProvider::default() // common domains bundled
);

// Validate an address
$result = $validator->validate('ceo@gamil.com');

// Access the structured result
$result->isValid();             // format-only validity (bool)
$result->isSendable();          // domain has A/AAAA and MX (bool)
$result->getReasons();          // list<string> format/DNS reasons
$result->getWarnings();         // list<string> (e.g. deny_list:<name>)
$result->getNormalized();       // ascii-lower-cased domain, same local part
$result->getSuggestion();       // suggested corrected address or null
$result->getSuggestionScore();  // 0.0–1.0 confidence score or null
$result->getDomainExists();     // ?bool
$result->getHasMx();            // ?bool
$result->getLists();            // list<ListOutcome>

Example JSON (via json_encode($result)):

{
  "query": "ceo@gamil.com",
  "corrections": {
    "normalized": "ceo@gmail.com",
    "suggestion": "ceo@gmail.com",
    "suggestionScore": 0.92
  },
  "simpleResults": {
    "formatValid": true,
    "isSendable": true,
    "hasWarnings": false
  },
  "reasons": [],
  "warnings": [],
  "dns": { "domainExists": true, "hasMx": true },
  "lists": []
}

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Domain suggestions & distance metrics

By default the validator uses a curated set of popular domains and Levenshtein distance. You can provide your own list and choose Damerau–Levenshtein:

use Dartcafe\EmailValidator\Suggestion\ArrayDomainSuggestionProvider;
use Dartcafe\EmailValidator\Suggestion\Distance;

// Provide your own candidate domains:
$domains = ['gmail.com', 'yahoo.com', 'outlook.com'];

// Choose the metric (LEVENSHTEIN | DAMERAU_LEVENSHTEIN)
$suggestions = ArrayDomainSuggestionProvider::fromArray($domains, Distance::DAMERAU_LEVENSHTEIN);

$validator = new EmailValidator(suggestions: $suggestions);
$res = $validator->validate('user@gmil.com');

$res->getSuggestion();       // "user@gmail.com"
$res->getSuggestionScore();  // e.g. 0.93

The score is a normalized similarity in [0.0, 1.0] (1.0 = identical, ~0.9 strong typo‑fix candidate, <0.5 usually weak).

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Deliverability (DNS)

Deliverability is heuristic: the validator checks MX first, then A/AAAA fallback.

• isSendable() is true only if domain resolves and MX exists.
• reasons may contain domain_not_found or no_mx.

Custom DNS is possible by implementing:

namespace Dartcafe\EmailValidator\Contracts;

interface DnsResolver
{
    /** @return array{0:?bool,1:?bool} [domainExists, hasMx] */
    public function check(string $asciiLowerDomain): array;
}

and passing it into the validator’s constructor.

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Lists: allow/deny with a pluggable provider

The library defines a minimal interface:

namespace Dartcafe\EmailValidator\Contracts;

use Dartcafe\EmailValidator\Value\ListOutcome;

interface ListProvider
{
    /**
     * @return list<ListOutcome>
     */
    public function evaluate(string $normalizedAddress, string $normalizedDomain): array;
}

Return ListOutcome objects (type: allow|deny, checkType: address|domain, matched, …). Deny matches are reported as warnings (do not change isSendable()).

You can write your own provider (DB/file/memory). A lightweight INI/Text adapter is available in the demo; production apps usually inject their own provider.

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REST endpoint (optional)

The package ships an OpenAPI description (public/openapi.json) for a tiny REST API:

• GET /validate?email=...
• POST /validate with {"email": "..." }
• GET /health

You can wire these routes in any micro-router or reuse the demo app.

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OpenAPI

• File: public/openapi.json
• Version in spec is kept in sync with releases via docs/OpenApiConfig.php and the release script.

Generate (in the lib):

composer run openapi:generate

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Types & DTOs

• Dartcafe\EmailValidator\Value\ValidationResult (mutable, JSON‑serializable)
• Dartcafe\EmailValidator\Value\ListOutcome
• Suggestion types:
  • Dartcafe\EmailValidator\Value\SuggestedDomain (domain + score)

Everything is annotated for Psalm and IDEs.

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Quality

# coding standards
composer cs
composer cs:fix

# static analysis
vendor/bin/psalm --no-cache

# tests
composer test

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License

MIT © René Gieling

See LICENSE.