best_form_validator

Demo

Best Form Validator Demo

A high-performance, zero-initialization form validation package for Flutter and Dart.

Instant. Context-free. No async setup.
Drop validators directly into TextFormField.validator — no BuildContext, no await, no boilerplate.

Why `best_form_validator`?

Feature	Standard Flutter	`best_form_validator`
Phone regex	Write your own	Built-in 52 countries 🌍
Local number formats	Manual conversion	Auto-normalized ✅
Async startup	N/A	Zero-init (synchronous) 🚀
Translations	Manual `if-else`	25 languages built-in
Chaining validators	Nested callbacks	`MultiValidator([...])`
URL validation	Write your own	Built-in HTTP/HTTPS ✅
Financial validation	External packages	Native Luhn / IBAN 💳
Unicode names	ASCII regex only	Arabic, CJK, Devanagari…

Features

Zero-Initialization — synchronous, no startup code required
Phone Validation — 52 countries, accepts local formats (03001234567) and international formats (+923001234567)
GB / UK alias — both 'GB' (ISO 3166-1) and 'UK' work interchangeably
Email & Password — battle-tested regex + configurable strength rules
URL Validation — HTTP/HTTPS URLs with proper scheme and host checks
Password Strength — PasswordValidator.getPasswordStrength() returns a 0–5 score
Unicode Names — Latin, Arabic, Urdu, Hindi, Chinese, Japanese, Korean, and more
Age Validation — handles the birthday-not-yet-occurred edge case correctly
Time Validation — strict HH:mm / HH:mm:ss (rejects 25:99:99)
Financial Checks — Credit Card (Luhn Mod-10) & IBAN (MOD-97), both publicly exported
MultiValidator — chain validators, returns the first error
Localization — 25 language error messages, runtime-switchable
PhoneInputFormatter — TextInputFormatter for auto-spacing phone numbers

Installation

dependencies:
  best_form_validator: ^1.4.0

flutter pub get

Quick Start

import 'package:best_form_validator/best_form_validator.dart';

TextFormField(
  validator: (value) => Validators.validateEmail(value),
)

No initialization needed. Works immediately.

Localization Setup

Add FormLocalizations.delegate to your MaterialApp and call Validators.setLocale in the builder:

import 'package:flutter_localizations/flutter_localizations.dart';
import 'package:best_form_validator/best_form_validator.dart';

MaterialApp(
  localizationsDelegates: [
    GlobalMaterialLocalizations.delegate,
    GlobalWidgetsLocalizations.delegate,
    GlobalCupertinoLocalizations.delegate,
    FormLocalizations.delegate,
  ],
  supportedLocales: const [
    Locale('en'), Locale('es'), Locale('fr'), Locale('de'),
    Locale('ar'), Locale('ur'), Locale('hi'), Locale('zh'),
    Locale('pt'), Locale('ru'), Locale('it'), Locale('tr'),
    Locale('ja'), Locale('ko'), Locale('id'), Locale('ms'),
    Locale('th'), Locale('vi'), Locale('nl'), Locale('sv'),
    Locale('no'), Locale('fi'), Locale('da'), Locale('el'),
    Locale('fa'),
  ],
  builder: (context, child) {
    Validators.setLocale(Localizations.localeOf(context));
    return child!;
  },
)

Usage

Email

Validators.validateEmail('user@example.com');  // null (valid)
Validators.validateEmail('');                  // 'Email is required'
Validators.validateEmail('bad-email');         // 'Enter a valid email'

// Custom messages
Validators.validateEmail(
  'bad',
  requiredError: 'Please enter your email',
  invalidError: 'That email looks wrong',
);

URL

Validators.validateUrl('https://example.com');   // null (valid)
Validators.validateUrl('http://localhost:8080'); // null (valid)
Validators.validateUrl('example.com');           // error (missing scheme)
Validators.validateUrl('');                      // 'URL is required'

// Accept bare domains (prepends https://)
Validators.validateUrl('example.com', allowMissingScheme: true); // null (valid)

// Optional field
Validators.validateUrl('', isRequired: false);  // null (valid)

// Custom messages
Validators.validateUrl(
  'bad',
  requiredError: 'Please enter your website',
  invalidError: 'That URL looks wrong',
);

Phone — international & local formats

Both +923001234567 and 03001234567 are accepted for Pakistan:

// International format
Validators.validatePhone('+12025551234', 'US');      // null (valid)
Validators.validatePhone('+923001234567', 'PK');     // null (valid)

// Local format — auto-normalized before validation
Validators.validatePhone('03001234567', 'PK');       // null (valid)
Validators.validatePhone('07911123456', 'GB');       // null (valid)

// Both GB and UK are accepted for the United Kingdom
Validators.validatePhone('+447911123456', 'GB');     // null (valid)
Validators.validatePhone('+447911123456', 'UK');     // null (valid)

Normalize a local number to international format independently:

String intl = Validators.normalizePhone('03001234567', 'PK');
// → '+923001234567'

Supported countries (52): US, CA, GB, UK, FR, DE, IN, AU, BR, CN, JP, MX, RU, ZA, NG, EG, KE, GH, SA, AE, IT, ES, SE, NO, FI, DK, NL, BE, CH, AT, PT, GR, TR, IR, PK, BD, LK, TH, MY, SG, ID, PH, VN, KR, HK, TW, NZ, AF, AL, DZ, AR, AZ, BH

TextFormField(
  decoration: InputDecoration(labelText: 'Phone', hintText: '+1 234 567 8900'),
  inputFormatters: [PhoneInputFormatter()],       // auto-formats as user types
  validator: (v) => Validators.validatePhone(v, 'US'),
  keyboardType: TextInputType.phone,
)

Password

// Basic (min 6 chars)
Validators.validatePassword('secret');

// Full strength check
Validators.validatePassword(
  'MyP@ssw0rd',
  checkLength: true,
  minLength: 8,
  checkNumberAndLetter: true,
  checkSpecialCharacter: true,
  checkLowerCase: true,
  checkUpperCase: true,
);

// Password strength score (0–5)
int score = PasswordValidator.getPasswordStrength('MyP@ssw0rd'); // 5

Name — Unicode aware

Validators.validateName('John Doe');      // null – Latin
Validators.validateName('José García');   // null – accented
Validators.validateName('محمد علي');     // null – Arabic
Validators.validateName('王芳');          // null – Chinese
Validators.validateName('राज कुमार');    // null – Hindi (Devanagari)
Validators.validateName('Mary-Jane');    // null – hyphenated
Validators.validateName("O'Brien");      // null – apostrophe
Validators.validateName('John123');      // error – digits not allowed

Age

Validators.validateAge('2000-01-15', 18);          // null if ≥18
Validators.validateAge(DateTime(2000, 1, 15), 18); // DateTime also accepted

Validators.validateAge(
  '2010-06-01',
  18,
  invalidError: 'You must be at least 18 years old',
);

Date

Validators.validateDate('2024-01-15'); // null (valid)
Validators.validateDate('not-a-date'); // error

Time

Validators.validateTime('14:30');      // null – HH:mm
Validators.validateTime('14:30:00');   // null – HH:mm:ss
Validators.validateTime('25:99:99');   // error – out of range (fixed in v1.3.0)
Validators.validateTime('00:00:00');   // null – midnight

Financial — Credit Card & IBAN

// Credit card (Luhn Mod-10) — spaces and dashes stripped automatically
Validators.validateCreditCard('4111 1111 1111 1111'); // null (valid Visa test)
Validators.validateCreditCard('1234 5678 9012 3456'); // error

// Direct class usage
FinancialValidators.validateCreditCard('4111111111111111');

// IBAN (MOD-97) — spaces stripped, case-insensitive
Validators.validateIBAN('GB82 WEST 1234 5698 7654 32'); // null (valid)
Validators.validateIBAN('INVALID');                      // error

// In a TextFormField
TextFormField(
  validator: (v) => Validators.validateCreditCard(v),
  keyboardType: TextInputType.number,
)

MultiValidator — chain validators

TextFormField(
  validator: MultiValidator([
    (v) => Validators.validateName(v),
    (v) => (v != null && v.length < 2) ? 'Too short' : null,
  ]),
)

Complete Form Example

import 'package:flutter/material.dart';
import 'package:best_form_validator/best_form_validator.dart';

class RegistrationForm extends StatefulWidget {
  const RegistrationForm({super.key});
  @override
  State<RegistrationForm> createState() => _RegistrationFormState();
}

class _RegistrationFormState extends State<RegistrationForm> {
  final _formKey = GlobalKey<FormState>();

  void _submit() {
    if (_formKey.currentState!.validate()) {
      ScaffoldMessenger.of(context)
          .showSnackBar(const SnackBar(content: Text('Success!')));
    }
  }

  @override
  Widget build(BuildContext context) {
    return Form(
      key: _formKey,
      child: ListView(
        padding: const EdgeInsets.all(16),
        children: [
          TextFormField(
            decoration: const InputDecoration(labelText: 'Full Name'),
            validator: (v) => Validators.validateName(v),
          ),
          const SizedBox(height: 12),
          TextFormField(
            decoration: const InputDecoration(labelText: 'Email'),
            validator: (v) => Validators.validateEmail(v),
            keyboardType: TextInputType.emailAddress,
          ),
          const SizedBox(height: 12),
          TextFormField(
            decoration: const InputDecoration(
              labelText: 'Phone',
              hintText: '+1 555 000 0000 or local format',
            ),
            inputFormatters: [PhoneInputFormatter()],
            validator: (v) => Validators.validatePhone(v, 'US'),
            keyboardType: TextInputType.phone,
          ),
          const SizedBox(height: 12),
          TextFormField(
            decoration: const InputDecoration(
              labelText: 'Password',
              helperText: 'Min 8 chars, upper, lower, number, special',
            ),
            obscureText: true,
            validator: (v) => Validators.validatePassword(
              v,
              checkLength: true,
              minLength: 8,
              checkNumberAndLetter: true,
              checkSpecialCharacter: true,
              checkLowerCase: true,
              checkUpperCase: true,
            ),
          ),
          const SizedBox(height: 12),
          TextFormField(
            decoration: const InputDecoration(
              labelText: 'Birth Date',
              hintText: 'yyyy-MM-dd',
            ),
            validator: (v) => Validators.validateAge(v, 18,
                invalidError: 'Must be at least 18 years old'),
          ),
          const SizedBox(height: 24),
          ElevatedButton(
            onPressed: _submit,
            child: const Text('Register'),
          ),
        ],
      ),
    );
  }
}

API Reference

`Validators` (convenience façade)

Method	Description
`validateEmail(value)`	Standard email format
`validateUrl(value, {...})`	HTTP/HTTPS URL with scheme and host checks
`validatePhone(value, isoCode)`	52 countries, auto-normalizes local formats
`normalizePhone(value, isoCode)`	Convert local to international format
`validatePassword(value, {...})`	Configurable password rules
`validateName(value)`	Unicode-aware name validation
`validateAge(value, minimumAge)`	Minimum age from birth date
`validateDate(value)`	Parseable date string
`validateTime(value)`	Strict HH:mm or HH:mm:ss
`validateCreditCard(value)`	Luhn algorithm (Mod-10)
`validateIBAN(value)`	ISO 13616 MOD-97
`setLocale(locale)`	Set global error message language

`PasswordValidator`

Method	Description
`validate(value, {...})`	Same as `Validators.validatePassword`
`getPasswordStrength(value)`	Returns int 0–5 entropy score

`PhoneValidator`

Method	Description
`validatePhoneNumber(value, isoCode)`	Direct phone validation
`normalizePhone(value, isoCode)`	Local → international conversion

`UrlValidator`

Method	Description
`validate(value, {...})`	Same as `Validators.validateUrl`

`FinancialValidators`

Method	Description
`validateCreditCard(value)`	Luhn check, strips spaces/dashes
`validateIBAN(value)`	MOD-97 check, strips spaces

`MultiValidator`

MultiValidator([validator1, validator2, ...])

Calls each validator in order and returns the first non-null error.

`PhoneInputFormatter`

A TextInputFormatter that auto-spaces phone numbers as the user types (+XXX XXX XXX XXX).

Supported Languages (25)

en es fr de ar ur hi zh pt ru it tr ja ko id ms th vi nl sv no fi da el fa

Platform Support

Android	iOS	Web	Windows	macOS	Linux
✅	✅	✅	✅	✅	✅

Requirements

Dart SDK: >=3.0.0 <4.0.0
Flutter: >=3.0.0
Dependencies: intl ^0.20.2 (only direct dependency)

Contributing

Fork the repository
Create your feature branch (git checkout -b feature/my-feature)
Commit your changes (git commit -m 'Add my feature')
Push to the branch (git push origin feature/my-feature)
Open a Pull Request

Please file bugs and feature requests in our issue tracker.

License

MIT — see LICENSE.

Maintained By

GreeLogix — Flutter, Laravel & AI Development Agency
🌐 https://greelogix.com
📩 hello@greelogix.com

Other Flutter Packages by GreeLogix

Package	Description
quick_popup_manager	Smart popup, dialog & overlay management
smart_form_toolkit	Advanced form toolkit with ready-to-use widgets
safe_json_mapper	Type-safe JSON parsing and mapping
flutter_telescope	Debugging, logging & app insights toolkit

See CHANGELOG.md for a full history of changes.

best_form_validator

Demo

Why `best_form_validator`?

Features

Installation

Quick Start

Localization Setup

Usage

Email

URL

Phone — international & local formats

Password

Name — Unicode aware

Age

Date

Time

Financial — Credit Card & IBAN

MultiValidator — chain validators

Complete Form Example

API Reference

`Validators` (convenience façade)

`PasswordValidator`

`PhoneValidator`

`UrlValidator`

`FinancialValidators`

`MultiValidator`

`PhoneInputFormatter`

Supported Languages (25)

Platform Support

Requirements

Contributing

License

Maintained By

Other Flutter Packages by GreeLogix

Libraries

best_form_validator package

best_form_validator

Demo

Why best_form_validator?

Features

Installation

Quick Start

Localization Setup

Usage

Email

URL

Phone — international & local formats

Password

Name — Unicode aware

Age

Date

Time

Financial — Credit Card & IBAN

MultiValidator — chain validators

Complete Form Example

API Reference

Validators (convenience façade)

PasswordValidator

PhoneValidator

UrlValidator

FinancialValidators

MultiValidator

PhoneInputFormatter

Supported Languages (25)

Platform Support

Requirements

Contributing

License

Maintained By

Other Flutter Packages by GreeLogix

Libraries

best_form_validator package

Why `best_form_validator`?

`Validators` (convenience façade)

`PasswordValidator`

`PhoneValidator`

`UrlValidator`

`FinancialValidators`

`MultiValidator`

`PhoneInputFormatter`