From 2014 to 2018 I worked at LoveCrafts, first on the e-commerce platform and then on the Social API team.
The e-commerce platform is a heavily customised Magento Enterprise installation, with integrations to the other systems the business runs on.
Payment, email, product information management and search were all separate systems that had to agree with each other, which is where most of the integration work was.
I then worked on the Social API team through to 2018, building central APIs and microservices for the LoveCrafts social network using code-generation techniques.
Generating the API layer rather than hand-writing it keeps a large number of services consistent with each other, which matters more as the number of services grows.
This was the engagement where I moved from PHP e-commerce work towards the API and cloud systems I mostly work on now.