LIVRLanguage Independent Validation Rules

Describe valid data once, as a declarative schema. Get the same validation, the same output and the same error codes in JavaScript, Perl, PHP, Python, Go, Erlang and more.

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Validation rules

Playground

rules

{
  name:    'required',
  email:   ['required', 'email'],
  age:     ['positive_integer', { min_number: 18 }],
  address: { nested_object: {
    city: 'required',
    zip:  'positive_integer'
  }}
}

input

{
  email: 'john@', age: 16, role: 'admin',
  address: { city: 'Kyiv', zip: 'O1001' }
}

errors Invalid

{
  "name": "REQUIRED",
  "email": "WRONG_EMAIL",
  "age": "TOO_LOW",
  "address": {
    "zip": "NOT_POSITIVE_INTEGER"
  }
}

📝

Declarative and portable

Rules are plain data. Store them as JSON and share one schema between the backend, the frontend and services written in other languages.

🛡️

Strict by default

Fields without rules are removed from the output, so data that is not explicitly allowed never reaches your code.

🏷️

Error codes, not messages

Errors are readable codes shaped like your data, for example { email: 'WRONG_EMAIL' }. They are easy to translate and to map to your UI.

🌳

Hierarchical data

Validate nested objects, lists and lists of different objects. Get errors for every field in a single pass.

✂️

Built-in modifiers

Trim, lowercase, set defaults and clean values in the same pipeline that validates them.

🧩

Extensible

Add your own rules, or combine existing ones into reusable aliases with custom error codes. Aliases work in every implementation.

Try it right here

Edit the rules or the input. The result is computed live in your browser by the JavaScript implementation, and every other implementation returns exactly the same.

Live example · edit rules or inputOpen in playground

rules

{
    name: 'required',
    email: ['required', 'email', 'to_lc'],
    gender: { one_of: ['male', 'female'] },
    password: ['required', { min_length: 10 }],
    password2: { equal_to_field: 'password' }
}

{
    name: 'required',
    email: ['required', 'email', 'to_lc'],
    gender: { one_of: ['male', 'female'] },
    password: ['required', { min_length: 10 }],
    password2: { equal_to_field: 'password' }
}

input

{
    name: 'John',
    email: 'John@Example.com',
    gender: 'male',
    password: 'mypassword1',
    password2: 'mypassword1',
    is_admin: true
}

{
    name: 'John',
    email: 'John@Example.com',
    gender: 'male',
    password: 'mypassword1',
    password2: 'mypassword1',
    is_admin: true
}

Validoutput

{
  "name": "John",
  "email": "john@example.com",
  "gender": "male",
  "password": "mypassword1",
  "password2": "mypassword1"
}

More examples →

Implementations

One specification and one shared test suite, many languages.

PHP

Lua

All implementations and test suite results →

Used by

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LIVRLanguage Independent Validation Rules

rules

input

errors Invalid

Declarative and portable

Strict by default

Error codes, not messages

Hierarchical data

Built-in modifiers

Extensible

Try it right here ​

Implementations ​

Used by ​

Try it right here

Implementations

Used by