My past projects, here on freelancer, include 9 mailchimp integrations with/plugins for wordpress.
I have extensive experience in websites development (+10 years), Html+Css+JavaScript/jQuery (+10 years), wordpress plugins development (+5 years), Database development - MsSql, MySql, Firebird (+9 years) and in 2013 i become Zend Certified Engineer with +7 years of experience in php development.