About

#What this site is for

This site reports the TLS version your client used to reach it. TLS is the protocol that encrypts traffic between your browser and the websites you visit. That protocol secures your connection to the websites you use and makes sure that only you and the code running the websites can see your private data like passwords, credit card numbers, and cookies.

Newer versions of TLS are faster and harder to attack. Most browsers now negotiate TLS 1.3 by default. The older TLS 1.0 and TLS 1.1 are extremely insecure. And TLS 1.2 is slower and less secure through the many insecure option it supports (like cipher suites without forward secrecy).

The home page of tlsversion.com shows whatever version your browser and this server settled on for that request. If you'd rather have it as data, fetch /v1/version.json.

#JSON API

Tlsversion.com has a simple JSON API that returns the TLS version your client negotiated with this server. The endpoint is /v1/version.json and it returns a JSON object like this:

{
    "version": "TLS 1.3"
}

#Relationship to How’s My SSL?

Tlsversion.com is the younger sibling to How’s My SSL?, which is a more full-featured web TLS client testing site. Tlsversion.com is a simpler, more focused site that just reports the TLS version your client negotiated with this server. If all you need is to know the TLS version, tlsversion.com is the site for you. If you want to know more about your client and its TLS configuration, use How’s My SSL?.