Getting Started with gRPC: What You Need to Know

In the evolving world of APIs and real-time communications, gRPC has emerged as a powerful protocol for microservices (If you want to know more about microservices, check our blog here – Microservices Architecture: A Beginner’s Guide to Scalable Systems) and client-server applications. But what exactly is gRPC? Why is it becoming popular among developers? And how does it compare to other technologies like REST, GraphQL, WebSockets, or Apache Kafka?

In this blog, we’ll explain gRPC in a simple way — what it is, why it’s useful, how it compares to other technologies, and what it’s built on. Whether you’re new to gRPC or just curious about how it works, this guide is for you.

What is gRPC?

• gRPC (gRPC Remote Procedure Call) is an open-source, high-performance Remote Procedure Call framework developed by Google. It enables communication between client and server applications, even if they’re written in different programming languages.
• In simple terms, gRPC lets you define a service and then specify methods that can be called remotely with input and output types
• Think of it like this: gRPC lets one app call a function from another app, even if that app is running on a different computer or server. It feels like calling a regular function, but it actually works over the internet.
• gRPC uses something called Protocol Buffers (Protobuf) to define the messages and services. Protobuf makes the data smaller and faster to send than regular JSON used in most APIs, which helps gRPC work very quickly and efficiently.

Why is gRPC required?

Here are some key reasons why gRPC is being widely adopted:

• Performance & Speed: gRPC uses HTTP/2, which is much faster than HTTP/1.1, and it sends data in binary format instead of JSON, resulting in lower payload size.
• Cross-language support: gRPC supports multiple languages like Java, Python, Go, Node.js, C++, Ruby, etc., allowing teams to build services in the languages they are comfortable with.
• Streaming Support: It supports client, server, and bidirectional streaming making it ideal for real-time communication.
• Contract-first API Development: Using Protocol Buffers, you define your API structure upfront. This ensures both the client and server follow the same rules, helping avoid bugs and miscommunication between services.
• Ideal for Microservices: In distributed systems where services need to talk to each other quickly and reliably, gRPC fits perfectly.

How is gRPC Used in Everyday Applications?

1.Live Chat in Customer Support

In chat systems, REST requires constant polling to check for new messages, which wastes resources and causes lag. gRPC allows two-way streaming, so both client and server can send messages instantly without polling.

2.Multi-language Microservices in E-commerce

E-commerce platforms often use different programming languages for different services. For example, the cart service might be in Node.js and the payment service in Python. gRPC helps them talk to each other easily using a common protocol (Protobuf), avoiding the need to rewrite code.

3.Stable Internal Communication in Microservices
Large applications with many microservices need to share data reliably. REST APIs can become hard to manage with changes over time. gRPC uses strongly-typed messages defined in Protobuf, so all services know exactly what to send and receive, reducing bugs.

4.Fast Communication in CI/CD Systems
In DevOps pipelines, tools like build runners, test executors, and deploy scripts need to talk quickly. REST APIs can be slow and add delay. gRPC makes these internal calls faster and lighter, helping pipelines run smoothly.

Not Just gRPC: Meet the Alternatives

1. REST (Representational State Transfer)
   • How it works: REST uses HTTP and JSON for communication, following a stateless request-response model.
   • Pros: Simple, widely adopted, easy to test and debug.
   • Cons: Lacks efficient binary serialization, no native streaming, slower compared to gRPC.
2. GraphQL
   • How it works: A query language developed by Facebook that allows clients to request exactly the data they need.
   • Pros: Flexible querying, reduces over-fetching, good for frontend-heavy apps.
   • Cons: More complex server-side implementation, no built-in streaming like gRPC.
3. QUIC
   • How it works: A transport layer protocol built on UDP by Google, designed to improve HTTP/2’s shortcomings.
   • Pros: Faster connection establishment, lower latency, better mobile performance.
   • Cons: Still evolving, limited support compared to TCP.
4. WebSockets
   • How it works: Provides full-duplex communication over a single TCP connection.
   • Pros: Real-time bi-directional data transfer, great for chat or gaming apps.
   • Cons: No built-in data schema enforcement or language bindings like gRPC.
5. Apache Kafka
   • How it works: A distributed streaming platform that publishes and subscribes to streams of records.
   • Pros: Extremely reliable, scalable, great for event-driven architecture.
   • Cons: Higher learning curve, not suitable for synchronous APIs.
6. Apache Thrift
   • How it works: A software framework from Apache for scalable cross-language services, similar to gRPC.
   • Pros: Cross-language support, compact serialization.
   • Cons: More complex than gRPC, lacks modern features like HTTP/2 and built-in streaming.

Inside gRPC: Technologies It’s Built On

Let’s explore the powerful tech foundation that makes gRPC fast, reliable, and efficient.

1. HTTP/2 – The Backbone Transport Protocol
   • gRPC is built on top of HTTP/2, a major improvement over HTTP/1.1
   • Key Features of HTTP/2:
     • Multiplexing: Multiple requests/responses share a single connection, removing the need for multiple TCP connections.
     • Header Compression: Uses HPACK to compress headers, reducing payload size and improving speed.
     • Request Prioritization: Helps clients signal which streams are more important.
     • Binary Framing: Uses a binary protocol instead of textual, enabling faster parsing and reduced ambiguity.
   • Why does it matter for gRPC?
     • HTTP/2 enables gRPC to support real-time communication, bidirectional streaming, and faster request/response handling with less overhead and fewer round trips.
2. Protocol Buffers (Protobuf) – The Data Format
   • Protocol Buffers (Protobuf) is Google’s language-neutral, platform-neutral, and extensible way of serializing structured data.
   • Benefits of Protobuf:
     • Compact: Smaller and faster than JSON or XML.
     • Strongly Typed: Helps catch bugs at compile-time.
     • Schema-Driven: Contracts are enforced through .proto files.
     • Cross-Language Support: Compatible with Go, Java, Python, Node.js, C++, and more.
   • Why does it matter for gRPC?
     • gRPC relies on Protobuf to encode messages in a highly efficient format that reduces payload size, speeds up transmission, and boosts overall system performance.
3. TCP – The Reliable Transport Layer
   • Under the hood, gRPC runs over TCP via HTTP/2.
   • Why TCP is essential:
     • Reliable Transmission: Ensures ordered, loss-free delivery of packets.
     • Persistent Connections: Reduces the need for reconnection for each request.
     • Congestion Control: Manages network load efficiently using algorithms like BBR or CUBIC.
   • Bonus: TCP vs UDP
     • Unlike UDP, TCP guarantees reliability and order, making it perfect for use cases like financial transactions, remote procedure calls, and database interactions where precision is critical.
4. RTT (Round Trip Time) – Measuring Latency Efficiency
   • RTT (Round-Trip Time) is the time it takes for a request to go from a client to a server and back.
   • How gRPC optimizes RTT:
     • Connection Reuse: Once established, HTTP/2 connections are kept alive.
     • TLS 1.3 Support: TLS 1.3 requires only 1 RTT for handshaking, reducing setup time.
     • No Head-of-Line Blocking: With HTTP/2 multiplexing, one slow request doesn’t block others — unlike HTTP/1.1.
     • Zero RTT for Subsequent Calls: After the initial handshake, subsequent gRPC requests can start with zero additional RTT if the connection is idle but alive.
5. Streaming Support
   • Thanks to HTTP/2, gRPC natively supports:
     • Unary RPC: Single request–response (like REST).
     • Server Streaming: Client sends a request, server sends multiple responses.
     • Client Streaming: Client sends a stream of data.
     • Bidirectional Streaming: Both client and server can send data streams simultaneously.
   • This keeps RTT consistently low even in chatty or real-time systems like chat apps, live dashboards, IoT data flows, etc.

Conclusion

gRPC is not here to replace REST, GraphQL, or WebSockets entirely, but it provides a faster, more efficient alternative for use cases like microservices communication, real-time data transfer, and cross-language APIs.

If you’re building modern distributed systems, want better performance, and care about schema-first API development, then gRPC is definitely worth exploring.