[theOnliest]

We (FastMail) use it in production, and all backend development is in Perl for all the products. Booking.com, cPanel, Craigslist, and ZipRecruiter all have sizable Perl codebases, as do many others.

[setquk]

As a FastMail customer I use Perl then!

You should have skipped cPanel though from that list. That doesn’t build credibility ;)