Client Certificates (mTLS) in ProjectX42

Client certificates (mTLS) in ProjectX42

Mutual TLS (mTLS), also called client certificate authentication, is an advanced security option. On top of your normal username and password, the app presents a client certificate that your server (or the reverse proxy in front of it) checks before it even allows a connection.

When would I use this?

mTLS is for advanced setups where you want an extra layer of protection on your remote connection — for example, when your ProjectX42 server sits behind a reverse proxy (such as NGINX) configured to require a client certificate. Only devices that hold a valid certificate can reach the server at all.

How the app supports it

If your server requires a client certificate, the ProjectX42 companion app will prompt you to select the certificate installed on your device during setup. Once chosen, the app presents it automatically on every connection.

Setting it up

1. Configure your reverse proxy / server to request and verify client certificates.
2. Install the client certificate on your phone.
3. Add your server in the app — when prompted, pick the installed certificate.

If you're just getting started and don't run a reverse proxy, you don't need mTLS. See Connection security for the everyday options, or Getting Started to set up your server.