What is gRPC?

You are likely hearing your engineering team throw around terms regarding how your application talks to itself. As you scale from a simple MVP to a more complex architecture, the way different parts of your software communicate becomes a bottleneck. You might hear debates about REST versus something called gRPC.

At its core, gRPC is a modern open-source high performance Remote Procedure Call (RPC) framework that can run in any environment. It was originally developed by Google to handle their massive internal infrastructure needs.

The concept of an RPC is not new. It essentially allows a program on one computer to execute code on another computer remotely. It implies that the action feels like a local function call to the developer writing the code.

However, gRPC takes this old concept and supercharges it for modern distributed systems. It creates a bridge between services that is incredibly fast and strictly defined. For a founder, this technology represents a shift toward efficiency and rigor in how your digital product is built.

To understand why gRPC is different, you have to look at the engine under the hood. Most web traffic today runs on JSON text sent over HTTP/1.1. This is human-readable and flexible, but it is also heavy and inefficient.

gRPC changes the transport mechanism and the language used to speak it.

It typically uses Protocol Buffers (Protobuf) instead of JSON. Protocol Buffers are Google’s language-neutral, platform-neutral, extensible mechanism for serializing structured data. Think of XML or JSON, but smaller, faster, and simpler.

When your service sends data via gRPC, it does not send a text file like this:

{ "name": "Ben", "id": 123 }

Instead, it sends a binary stream. This binary format is much smaller than the equivalent text format. This means less bandwidth usage and faster transmission times.

Furthermore, gRPC is built on top of HTTP/2. This is a major upgrade from the standard HTTP/1.1 used by many REST APIs. HTTP/2 allows for multiplexing. This means multiple requests and responses can be sent over a single TCP connection at the same time.

In the old world, if you needed to fetch a user, their orders, and their settings, your app might open three separate connections or wait for one to finish before starting the next. With gRPC and HTTP/2, all those requests flow simultaneously over a single open line.

One of the most significant business impacts of choosing gRPC is the enforcement of structure. In a startup, moving fast often means breaking things. API documentation gets outdated. One developer changes a field name in the code, and suddenly the frontend breaks because it was expecting the old name.

gRPC solves this through the use of .proto files.

These files act as a strict contract between services. You define exactly what data is being sent and what data is being received before you write a single line of logic.

This forces a design-first approach. Your teams must agree on the interface before they start coding.

Once the .proto file is defined, gRPC tooling can automatically generate code in multiple languages (Python, Go, Java, etc.) that adheres to that contract.

This drastically reduces integration bugs. If Team A changes the contract, the code generation for Team B will fail immediately during the build process, alerting everyone to the problem before it hits production.

For a growing organization, this type of automated discipline is invaluable. It reduces the communication overhead required to keep different engineering teams in sync.

This is the most common comparison you will encounter. REST (Representational State Transfer) is the industry standard for web APIs. It is flexible, widely understood, and easy to debug because you can read the JSON responses in a web browser.

So why would you choose one over the other?

• You are building public-facing APIs for third-party developers.
• You need the widest possible compatibility with browsers and simple clients.
• Speed and bandwidth are not your primary constraints.
• Your team needs flexibility to change data structures on the fly without breaking contracts immediately.

Choose gRPC when:

• You are building internal microservices that need to talk to each other constantly.
• Low latency is critical to your product performance.
• You are working in a polyglot environment where Service A is in Java and Service B is in Go.
• You are operating in low-bandwidth environments, such as IoT devices or mobile networks where data size matters.

REST focuses on resources. It is great for retrieving data objects. gRPC focuses on actions. It is great for triggering processes and complex workflows across servers.

Understanding the theory is helpful, but knowing where to apply it helps you make decisions. Here are specific scenarios where gRPC shines.

Microservices Architecture

If your startup is breaking a monolith into microservices, the chatter between those services will increase exponentially. If Service A calls Service B, which calls Service C, the latency adds up.

Using gRPC for this internal communication eliminates the overhead of parsing JSON at every step. It creates a high-speed internal network for your application logic.

Mobile Applications

Mobile devices often have unstable network connections. The efficiency of Protocol Buffers means the payload size is smaller. This results in faster load times for the end user and less battery drain on the device.

While gRPC support in browsers is still maturing (often requiring a proxy like gRPC-Web), native mobile apps can leverage the full power of gRPC directly.

Streaming Data

gRPC has first-class support for streaming. This isn’t just watching a video. It means a client can send a stream of data to the server, or the server can send a stream back, or both can happen at the same time.

Imagine a real-time dashboard for a logistics company. Instead of the client asking the server “where is the truck?” every second (polling), the server simply keeps a stream open and pushes the location update whenever it changes.

No technology is a silver bullet. Adopting gRPC comes with friction points that you must anticipate.

The primary hurdle is human. REST is the default language of the web. Almost every developer knows how to write a curl request or inspect a JSON packet. gRPC requires learning Protocol Buffers and the specific tooling around code generation.

Debugging is also harder. You cannot simply look at the network traffic and read what is happening because the data is in binary format. You need specific tools to decode the messages to understand what went wrong.

Furthermore, browser support is not as seamless as it is for REST. If your primary product is a web application accessed via Chrome or Safari, your team will need to implement a translation layer (proxy) to convert browser requests into gRPC calls.

There is also the question of rigidity. While strict contracts prevent errors, they can also slow down early-stage experimentation if your data model changes daily. You have to update the contract and regenerate the code every time you change a field.

As you evaluate this technology, ask your technical leaders about their comfort level with strict typing and schema definitions. gRPC is a tool for scale and precision. Ensure your business stage aligns with those needs.