As a Senior Software Engineer on the API team at Twilio, Guillaume Binet's typical day involves individual tasks like coding and code reviews in the mornings, followed by coordination with the team through standup meetings. The API engineering team has a transversal focus on topics such as usability, consistency, security, and works closely with other teams to present features and enhancements on the public API. To be successful, the ideal candidate should be open-minded about technologies and a good team player, willing to take on responsibilities from inception to production. Guillaume's job is challenging but also rewarding, allowing him to make a difference in changing the telecommunications industry.