pyvalidator

pyvalidator is a lightweight validation library for Python, inspired by Yup (JavaScript) and validator.js, designed to be clean, chainable, and compatible with serverless environments such as AWS Lambda.

It supports schema-based validation, standalone is_* functions (like is_email, is_cpf, etc.), and can validate raw AWS Lambda events transparently.

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Installation

pip install -e .

or if published later:

pip install pyvalidator

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Key Features

• Schema-based validation similar to Yup (string().required().email()).
• Built-in validations: email, URL, UUID, CPF, CNPJ, numeric, alpha.
• Accepts raw AWS Lambda event objects directly (API Gateway, SQS, SNS).
• Functional validators (is_email, is_url, is_cpf, etc.) similar to validator.js.
• Basic sanitizers included (trim, escape, normalize_email).
• No external dependencies.

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Basic Usage

Schema validation

from pyvalidator import Schema, string, number, boolean, ValidationError

user_schema = Schema({
    "email": string().required().email(),
    "cpf": string().required().cpf(),
    "age": number().min(18).max(99),
    "website": string().url().optional(),
    "is_active": boolean().optional(),
})

def handler(event, context):
    try:
        data = user_schema.validate(event)  # accepts full AWS Lambda event
        return {"statusCode": 200, "body": "validated"}
    except ValidationError as e:
        return {"statusCode": 400, "body": str(e.errors)}

Direct use of validators

from pyvalidator import is_email, is_url, is_cpf

is_email("[email protected]")   # True
is_url("https://example.com")  # True
is_cpf("390.533.447-05")    # True

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Available Field Types

Method	Description
string()	String validation
number()	Integer/float validation
boolean()	Boolean coercion/validation
Schema({})	Object/schema validation

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String Field - Methods

Method	Description
.required()	Field must be present and non-null
.optional()	Field is optional
.email()	Valid email address
.url()	Valid URL
.uuid()	Valid UUID
.cpf()	Valid Brazilian CPF
.cnpj()	Valid Brazilian CNPJ
.min(n)	Minimum number of characters
.max(n)	Maximum number of characters
.matches(regex)	Must match regex

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Number Field - Methods

Method	Description
.min(n)	Minimum numeric value
.max(n)	Maximum numeric value
.integer()	Must be an integer

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Sanitization Examples

from pyvalidator.sanitizers.string_sanitizers import trim, escape
from pyvalidator.sanitizers.email_sanitizers import normalize_email

trim("  test  ")             # "test"
escape("<script>")           # "&lt;script&gt;"
normalize_email("[email protected]")  # "[email protected]"

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Project Structure

pyvalidator/
├── __init__.py
├── schema/                 # Yup-style schema (string(), number(), boolean(), Schema)
├── validators/             # Functional-style validators (is_email, is_cpf, etc.)
├── sanitizers/             # trim, escape, normalize_email
├── tests/
└── setup.py

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Roadmap

• .strip_unknown() for removing unexpected fields
• .nullable(), .one_of(), .not_one_of()
• .date() and ISO8601 validation
• CEP and Brazilian phone validation
• PyPI publishing
• Automatic Lambda Layer packaging