Validators

0.35.0 · active · verified Sun Mar 29

Validators is a lightweight Python library designed for human-friendly data validation without the need for complex schemas or forms. It provides a wide array of simple functions to validate common data types such as email addresses, URLs, IP addresses, and more. On success, validator functions return `True`; on failure, they return a `ValidationFailure` object. The library is actively maintained, with frequent updates to add new validators and improve existing ones.

Warnings

breaking Version 0.35.0 dropped support for Python 3.8. Users on Python 3.8 or older must upgrade their Python version or use an older `validators` release.
Fix: Upgrade Python to 3.9+ or pin `validators` to `<0.35.0`.
breaking The `btc_address` validator was moved to the `crypto_addresses` submodule. Direct imports or calls to `validators.btc_address` will fail.
Fix: Update your code to use `validators.crypto_addresses.btc_address`.
gotcha Validator functions return `True` on success or a `ValidationFailure` object on failure. While `ValidationFailure` objects correctly evaluate to `False` in a boolean context, they are not `False` themselves. Access specific error details via attributes like `failure_object.message`, `failure_object.value`, etc.
Fix: Check the result in a boolean context (`if result:`) or inspect the `ValidationFailure` object's attributes for details (`if not result: print(result.message)`).
gotcha Be mindful of similarly named but distinct libraries like `validator` (for request validation with schema rules) and `validator-collection` (another collection of validation functions with a different API). Ensure you are installing and importing the correct `validators` library.
Fix: Double-check `pip install validators` and `import validators` to confirm you are using this specific library.

Install

pip install validators Install latest version

Imports

validators
```
import validators
```
All validator functions are directly accessible as attributes of the imported 'validators' module (e.g., validators.email()).

Quickstart

Demonstrates basic usage of `validators.email` and `validators.url`, and how to handle `ValidationFailure` objects.

import validators

email_to_check = "test@example.com"
is_valid_email = validators.email(email_to_check)

if is_valid_email:
    print(f"'{email_to_check}' is a valid email address.")
else:
    # ValidationFailure objects evaluate to False in a boolean context
    print(f"'{email_to_check}' is not a valid email address. Reason: {is_valid_email.message}")

url_to_check = "http://invalid.domain"
is_valid_url = validators.url(url_to_check)

if is_valid_url:
    print(f"'{url_to_check}' is a valid URL.")
else:
    print(f"'{url_to_check}' is an invalid URL. Reason: {is_valid_url.message}")

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