We create APIs using Laravel/Symfony or other similar PHP Frameworks.
We integrate 3rd Party APIs (eg. Machine Learning APIs like IBM Watson, communication APIs like Twilio or any other types of APIs).
We use MySQL, Postgresql, NoSQL databases or in-memory data structure store like Redis.
We architect the application to be scalable from the start.
We use queues (eg. Amazon SQS).
We use caching technologies.
We follow coding standards and best practices.
We do Unit Testing.
We handle data migration.