Over the past few months, I’ve been exposed to gRPC as a way of transferring data from a User Interface to a variety of microservices. Before I get my hands dirty with building my first gRPC service, I thought it would be important to identify some of the differences between gRPC and my go-to RESTful API. With this research, I hope to have a better understanding of gRPC and when I should use it in my application framework.
What are gRPC and RESTful APIs?
gRPC
Initially developed by Google, gRPC is an open-source communication framework. It’s built on HTTP/2, uses Protocol Buffers for messaging, and comes loaded with features like authentication and load balancing.
RESTful APIs
REST is all about standardizing communication between software using stateless interactions. When we say "RESTful APIs," we’re talking about APIs built using REST principles, often over HTTP and using JSON or XML for data transfer.
Messaging Format
gRPC
gRPC employs Protocol Buffers, a compact binary serialization format. It’s efficient in both size and speed, granting gRPC a performance advantage, especially in microservices architectures where service-to-service calls are frequent.
RESTful APIs
Typically, RESTful APIs utilize JSON or XML for data interchange. While human-readable and widely adopted, these formats can introduce overhead, both in terms of serialization/deserialization speed and message size.
Underlying Protocols
gRPC
gRPC is inherently bound to HTTP/2, benefiting from its features such as header compression, multiplexing, and server push.
RESTful APIs
Primarily built on HTTP/1.1, RESTful APIs can operate over HTTP/2 but aren't inherently designed to harness its advanced features.
Real-time Communication
gRPC
One of gRPC's standout features is its native support for multiple types of streaming, facilitating real-time data exchange.
RESTful APIs
REST, being stateless, primarily supports a request-response model. While streaming is achievable through workarounds, it's not a native feature like in gRPC.
Performance
gRPC
Thanks to Protocol Buffers and HTTP/2, gRPC offers efficient data transmission, which can be especially beneficial for high-frequency service interactions.
RESTful APIs
Although versatile, the inherent overhead of textual message formats (like JSON) can sometimes introduce latency, affecting performance.
Ecosystem and Tooling
gRPC
Tools like gRPC-Web make it feasible for browser clients to access gRPC services, and gRPC-Gateway can transform gRPC calls into RESTful ones, ensuring wider compatibility.
RESTful APIs
Being long-established, REST boasts a vast ecosystem, including tooling, libraries, and community support, making its integration and adoption smoother.
Design Methodologies
gRPC
gRPC advocates for a contract-first design philosophy. Service definitions are created upfront in .proto files, specifying service methods and message types, which ensures a robust contract between services.
RESTful APIs
REST’s flexibility means there's no strict contract enforcement. However, this flexibility necessitates careful design to maintain consistency.
Versioning and Forward Compatibility
gRPC
Protocol Buffers inherently support backward and forward compatibility, simplifying the evolution of services over time.
RESTful APIs
When updating services, it's essential to maintain compatibility for older versions. Common methods include appending version numbers in URLs, designating specific headers for versioning, or including version details within the message payload. Each method has its pros and cons, and the choice often depends on the application's architecture and user needs.
Conclusion
Based on this research, I feel that gRPC shines when an application demands fast, performant, and near-real time updates. Examples of these applications could be trading platforms and collaboration tools (like Figma!). I've used WebSockets in the past for building a chat application (who hasn't?) so I understand the concepts of full-duplex communication. What will I build with gRPC? Stay tuned...
