When we were recruiting for a Rails position PHP (in fact any dynamic
language) was fine if it also came with experience, I would guess that
7 years PHP should mean some good experience. If the rest of your CV
panned out you would have got an interview. Certification would have
counted for nothing. The truth is that after 7 years as a PHP
developer you shouldn’t need to prove anything other than you
understand web development as a whole rather than just programming. If
anyone with 7 years programming experience is still s ‘PHP programmer’
rather than a ‘web developer’ or just a plain programmer then that
would be a bad thing.
So honestly there is little you can do but polish up your CV so that
you stress that you are a web developer (list your accomplishments and
skills you have developed - databases, web servers, memcached, xml,
of PHP under their belt. That 7 years should mean something, you are
no longer a code monkey, you have been programming longer than most
startups have existed (the first Twitter message was 2006, the company
was founded in 2008 - you have been a web developer longer than
Twitter has existed for).
Make sure that you don’t undervalue yourself, a programmer with that
much experience should take to a new language without breaking sweat.
Your knowledge of web development is your asset not your knowledge
about the dark corners of a specific programming language.