Explore the fundamentals of building RESTful APIs using Symfony components in this informative conference talk from the International PHP Conference. Delve into the HTTP specification-based foundation provided by Symfony for creating robust APIs, with or without the full framework. Learn practical approaches to adapt models to desired representations, validate incoming data, and implement authentication strategies. Discover additional tools available when using the full Symfony framework, along with tips and tricks for effective API testing. Gain insights into creating custom frameworks, working with HTTP Foundation, PS7 Standard, Realizer, Annotations, Validator, and more. Understand concepts like First Responder, Jason Token, Level 3 API, Documentation Bundle, API Platform, and Symphonia through real-world use cases presented by Victoria Quirante from Limenius.