valid-8 is a free Chrome add-on developed by Blade-Marketing. This add-on falls under the category of Browsers and specifically the subcategory of Add-ons & Tools.

The main purpose of valid-8 is to detect emails on the screen and validate their authenticity using an API. Once emails are detected on a website, the add-on presents the user with a clickable button to "validate" these emails. This triggers an API call to the developer's server, where the email is sent for validation. The server then returns a result, which is displayed next to the email instead of the button. The possible results are "invalid", "valid", or "catch-all".

With valid-8, users can instantly validate their prospect's emails, ensuring the authenticity and accuracy of their contact information. This can be particularly useful for businesses and professionals who rely on email communication for their marketing and sales efforts.

Please note that valid-8 is available exclusively for the Chrome platform and is completely free to use. It offers a convenient and efficient solution for email validation within the browser environment.