You’re designing a mobile API (Android/iOS) that must use HTTPS, minimize bandwidth, and be easy to integrate. Which API architecture fits best?

gRPC-based APIs are the best fit because they use Protocol Buffers for serialization, which are highly efficient and minimize bandwidth compared to text-based formats like JSON or XML. gRPC also leverages HTTP/2 for multiplexing and streaming, further optimizing performance for mobile clients. Its strong typing and auto-generated client/server stubs make integration straightforward. RESTful APIs, while easy to integrate, typically use JSON or XML, which are more verbose and bandwidth-intensive than Protocol Buffers. MQTT is a messaging protocol, not an API architecture, primarily designed for IoT and publish/subscribe patterns, not direct API calls. SOAP-based APIs are generally more complex, verbose (XML-based), and have higher overhead, making them less suitable for bandwidth-constrained mobile environments.