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🚀 Enabling GZIP Compression in Spring Boot for Faster Web Apps

📅 Last Updated: June 2025

🛠️ Author: DevCorne2

📝 Table of Contents

  1. Introduction
  2. Why GZIP Compression?
  3. How GZIP Works
  4. Spring Boot GZIP Setup
  5. Configuration Properties
  6. Testing the GZIP Compression
  7. Advantages of GZIP Compression
  8. Best Practices
  9. Troubleshooting
  10. Conclusion

📌 Introduction

In modern web applications, speed and bandwidth optimization are critical. One simple yet effective way to improve performance is HTTP response compression using GZIP.

In this blog post, we’ll see how to enable GZIP compression in a Spring Boot application with zero external dependencies, saving bandwidth and speeding up page load times.

❓ Why GZIP Compression?

HTTP responses often include large payloads such as:

  • JSON responses from REST APIs
  • HTML content
  • Static files (CSS, JS, etc.)

GZIP reduces these response sizes significantly (up to 70–90%), which:

  • Reduces network latency
  • Improves page load time
  • Optimizes mobile performance
  • Saves server bandwidth

⚙️ How GZIP Works

  1. The client (browser or API consumer) sends a request with the header: 
   Accept-Encoding: gzip
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  1. If the server supports GZIP, it compresses the response and sends it with: 
   Content-Encoding: gzip
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  1. The client decompresses the response before consuming it.

✅ Spring Boot GZIP Setup

Spring Boot supports GZIP compression out of the box via embedded Tomcat, Jetty, or Undertow.

🔸 Step 1: No Dependency Needed

You don’t need to add any dependencies. GZIP is supported by the embedded servlet containers.

🔸 Step 2: Add Configuration

If you're using application.properties: 

server.compression.enabled=true
server.compression.mime-types=application/json,application/xml,text/html,text/xml,text/plain
server.compression.min-response-size=1024
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Or use application.yml: 

server:
  compression:
    enabled: true
    mime-types: application/json,application/xml,text/html,text/xml,text/plain
    min-response-size: 1024
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🔸 What Do These Properties Mean?

Property Description
server.compression.enabled Enables or disables compression
server.compression.mime-types Response content types to compress
server.compression.min-response-size Minimum size in bytes to trigger compression

🔍 Testing the GZIP Compression

You can test the setup in multiple ways:

🧪 Option 1: Curl 

curl -H "Accept-Encoding: gzip" -I http://localhost:8080/api/hello
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You should see:

Content-Encoding: gzip
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🧪 Option 2: Postman

  1. Open Postman.
  2. Set a custom header: 
   Accept-Encoding: gzip
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  1. Send the request.
  2. Check response headers for: 
   Content-Encoding: gzip
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🧪 Option 3: Browser Dev Tools

  1. Open Developer Tools (F12).
  2. Navigate to Network tab.
  3. Inspect any API call.
  4. Look for Content-Encoding: gzip under Response Headers.

🏆 Advantages of GZIP Compression

Benefit Description
🚀 Faster Load Times Compressing large JSON/HTML speeds up response times
📉 Lower Bandwidth Compressed payloads mean less data over the wire
📱 Mobile Friendly Reduces data usage for mobile clients
🌐 SEO Boost Page speed impacts search ranking
💵 Cost Efficient Reduces cloud bandwidth cost at scale

🛡️ Best Practices

  • Use GZIP for API responses, not for already compressed files (like .zip, .jpg, .png).
  • Set a reasonable min-response-size (e.g., 1024) to avoid compressing very small responses.
  • Benchmark performance to ensure compression doesn’t add noticeable CPU load.
  • Use content negotiation to serve GZIP only when the client supports it.
  • Use with TLS (HTTPS) for secure transmission of compressed data.

🧯 Troubleshooting

Problem Possible Fix
Content-Encoding header missing Check Accept-Encoding request header
Response not compressed Ensure mime-type and size match conditions
Still slow Use tools like GTMetrix or Lighthouse to check if GZIP is applied
Using WebFlux GZIP is not enabled by default in Netty; you need to add it manually (can provide steps if needed)

✅ Conclusion

GZIP compression is an easy win for Spring Boot applications to boost performance without extra libraries or code. By compressing JSON, HTML, and text responses, you make your app faster, more efficient, and scalable.

📚 References

👋 Need Help?

Leave a comment or contact me if you need help with:

  • GZIP in Spring WebFlux
  • GZIP with specific headers or content types
  • Performance testing scripts

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