HAProxy Certificate Question

[guardian]

Can I use the same certificate that I use for OpenVPN authentication to authenticate a client web browser on HAProxy?

Is the pfSense export format compatable with Android and web browsers.

I'm surprised that I haven't been able to find more on the web about using client certificates in Android - Everything is geared to the enterprise and is far to complicated for private/small business use. It seems to me like client certificates would be a very effective means of prioviding excellent security and allowing convenient access to internal web apps.

Thanks in advance for any advice/hints/suggestions.