From Stubby to gRPC: What is gRPC and why is it the future of service-to-service communication

Today’s digital world is increasingly faced with the importance of effective interaction between hundreds of independent microservices that make up modern software products. Now, REST is far from always being able to satisfy all requests and expectations regarding volume scaling and performance. This is where gRPC comes in. What is gRPC? It is a high-performance, multifunctional framework for remote procedure calls, developed by Google. But where did it all begin?

Stubby: The predecessor of gRPC 

The pioneer in this context was Stubby — an internal RPC framework created by Google in the distant 2000s. This framework ensured productive and secure interaction between the company’s various internal services. In the case of Stubby, local standards of interfaces, protocols, and serialization were used. Over time, it was concluded that this technology could bring results beyond the scope of Google. After all, in the outside world, companies face similar problems and scaling tasks. gRPC was introduced as an open and more advanced variation of gRPC, which became available to all developers worldwide in 2015.

What is gRPC, and how does it work? 

gRPC (Google Remote Procedure Call) is a framework that provides applications running on different servers with the ability to “communicate” with each other as if they were calling local functions. How is this possible? It’s all about automatically generated server and client stubs. These, in turn, are created based on specialized .proto files. gRPC uses Protocol Buffers (Protobuf), rather than text formats (as is the case with JSON in REST). This is called a binary serialization format — it is faster and at the same time less bulky. The additional use of HTTP/2 provides another advantage, as gRPC can support both bidirectional streams and multiplexed connections, as well as header compression.

Interaction modes in gRPC 

It is also worth noting in more detail what communication models are supported by gRPC. There are four of them in total:

  • Classic: Unary RP (request-response) 
  • Streaming data from server to client: Server streaming 
  • Stream of requests from client, server response at a time: Client streaming 
  • Both sides conduct a two-way stream at the same time: Bidirectional streaming 

All these modes enable the development of both ordinary APIs and systems with a higher level of real-time information exchange.

Key advantages of gRPC

  • Minimalism in terms of traffic volumes. Compactness of messages in Protobuf format is ideal for various mobile networks or gadgets with limited resources. 
  • Reliable contracts between services. The only verified source of information is .proto files, which significantly prevents misunderstandings between teams. 
  • Productivity. Binary serialization and HTTP/2 give gRPC a significant advantage over REST in terms of speed and code generation automation. Access to dozens of languages in the context of service and client generations greatly facilitates the development process. 
  • Flexibility. Any scenarios can be implemented thanks to streaming data transfer (for example, both second-by-second updates of stock quotes and live control of drones)

Disadvantages and challenges of gRPC 

Every coin always has two sides, so gRPC has several disadvantages, or rather limitations: 

  • Learning curve. Beginners may encounter inevitable misunderstandings related to code generation, the obligation to work with Protocol Buffers, and innovative approaches to APIs. 
  • Limited support in specific browsers. A typical browser does not provide full support for HTTP/2, so the use of a proxy comes to the rescue here (in the case of front-end applications). 
  • Compatibility. Unlike REST, which is supported almost everywhere, gRPC requires a pool of additional settings and infrastructure. 

However, all these difficulties are non-critical and are overcome every year thanks to the improvement and optimization of documentation, libraries, and practical cases.

Real-world applications 

gRPC is actively used in high-load systems that require maximum low latency and high speed at the same time: 

  • Financial services 
  • Mobile applications 
  • Gaming platforms 
  • IoT solutions

PFLB’s role in the world of gRPC 

We will not deny the fact that developing a service is only half the battle. It is also crucial to conduct testing in conditions as realistic as possible. This is what PFLB, a company specializing in testing the performance level of multifunctional digital systems, does. How exactly does PFLB do it? They implement complex load testing scenarios for gRPC services: simulating the simultaneous operation of several thousand users, checking the level of resistance to loaded traffic, and finding “weak spots” in stream processing. The deep professional expertise of the PFLB team guarantees both the identification of the problems themselves and the subsequent provision of recommendations for optimizing the architecture. PFLB guarantees that each of its clients’ gRPC services is always ready for high-performance workflows under real-world load conditions.

The future is here

The substantial advantages of gRPC contribute to its increasing introduction into the development sphere every day. Maximum efficiency, multilingualism, modern architecture, and adaptability — all these factors contribute to the fact that gRPC has vast potential to become the most promising tool for building a microservice ecosystem. The world is confidently moving towards the so-called decentralization, to the distribution of systems in which every byte and every millisecond acquires value. gRPC is a powerful solution in this case. This technology continues to develop and improve, but it has already proven its effectiveness in the most complex environments.

Conclusion 

The gRPC concept is not limited to the latest approach for building APIs. gRPC is a comprehensive framework that offers a vast array of capabilities, providing practical and reliable inter-service communication. This system is an excellent example of a logical response to the challenges of the modern digital world. Dynamic scaling of the number of remote procedure call systems, a request for fast and transparent interaction, and growth in data volumes. Undoubtedly, some preparation is required for implementing gRPC, but this is a fair price to pay for gaining a competitive advantage. Suppose you mix technical solutions with deep expertise in the context of performance testing, as PFLB does. In that case, it is already about long-term reliability, which is tested by real loads.