logo

Protobuffers vs JSON over HTTP

April 23, 2025

Protobuffers vs JSON over HTTP: Performance Showdown

In modern web applications and microservices, the efficiency of data transfer can significantly impact the overall performance of your systems. When it comes to sending data over HTTP, two popular formats stand out: JSON and Protocol Buffers (Protobuf). This blog explores the key differences between these formats and presents benchmark results that illustrate why binary protocols like Protobuf often outperform text-based alternatives like JSON. I know GRPC is what most of the world is using now, but I wanted to see how Protobuf compares to JSON over HTTP.

What are Protocol Buffers?

Protocol Buffers, or Protobuf, is Google's language-neutral, platform-neutral, extensible mechanism for serializing structured data. Unlike JSON, which is a text-based format, Protobuf is a binary serialization format. This means that data is encoded in a compact binary representation rather than human-readable text.

Key features of Protocol Buffers include:

  • Binary format for efficient serialization
  • Strongly typed schema definition
  • Forward and backward compatibility
  • Automatic code generation for multiple languages
  • Smaller payload size compared to text-based formats

JSON: The Ubiquitous Text Format

JSON (JavaScript Object Notation) has become the de facto standard for data interchange on the web. Its human-readable format and simplicity have made it incredibly popular for APIs and configuration files.

Key features of JSON include:

  • Human-readable text format
  • Language-independent data representation
  • Simple syntax with key-value pairs
  • Native support in JavaScript
  • Wide adoption across programming languages and frameworks

The Performance Test

To compare the performance of Protobuf and JSON, I created a simple benchmark that measures serialization and deserialization times for each format when transmitting data over HTTP. The test involves sending the same structured data using both formats and measuring the round-trip time.

Test Setup

  • A simple server and client written in Go
  • Identical data structures for both formats
  • Multiple rounds of requests to account for warm-up effects
  • Measurements in microseconds (µs) and milliseconds (ms)

The Results

Here's how the two formats performed:

Results of the benchmark

As you can see from the results, Protocol Buffers consistently outperformed JSON in terms of speed:

  • Round 1: Protobuf was more than 4 times faster than JSON
  • Round 2: Protobuf was about 1.25 times faster
  • Round 3: The performance difference narrowed, but Protobuf still edged out
  • Overall: On average, Protobuf was about 2.7 times faster than JSON

Why is Protobuf Faster?

Several factors contribute to Protocol Buffers' performance advantage:

  1. Binary Format: Protobuf encodes data in a compact binary format, which requires less bandwidth and has lower parsing overhead compared to text.

  2. Schema Definition: With a predefined schema, Protobuf knows exactly what to expect, eliminating the need for type inference during parsing.

  3. Efficient Serialization: Protobuf's serialization process is optimized for speed and size, resulting in faster encoding and decoding.

  4. Reduced Payload Size: Binary representation typically results in smaller data sizes, which means faster transmission over the network.

When to Choose Protobuf vs JSON

Despite Protobuf's performance advantages, JSON remains the right choice in many scenarios. Here's when to consider each:

Choose Protobuf when:

  • Performance is critical
  • You're working with large data volumes
  • Network efficiency is important
  • You have a well-defined, stable data structure
  • Language interoperability is needed for internal services

Choose JSON when:

  • Human readability is important
  • You need easy debugging
  • Browser compatibility is required
  • You want the simplest implementation
  • Your API is public-facing and needs to be accessible to a wide range of clients

Conclusion

While JSON is more human-friendly and widely supported, Protocol Buffers offer significant performance benefits that can be crucial for high-throughput systems or mobile applications where bandwidth and processing power are limited.

The benchmark results clearly show that for performance-critical applications, considering a binary protocol like Protobuf is worthwhile. However, the decision between JSON and Protobuf should ultimately depend on your specific use case, considering factors like team familiarity, tooling, client requirements, and whether the performance gain justifies the added complexity.

For many applications, a hybrid approach might be optimal – using Protobuf for internal service-to-service communication where performance matters most, while maintaining JSON interfaces for external APIs where compatibility and human readability are prioritized.

References

Source code