Course outline

01 · HTTP & REST APIs

02 · Databases & Persistence

03 · Authentication & Authorization

04 · API Design & gRPC

05 · Caching, Queues & Background Jobs

06 · Production-Ready Services

07 · Advanced Auth & Tenant Security

08 · Performance & Caching at Scale

09 · Testing & Release Confidence

Stage 3 · Build

Performance & Caching at Scale

Response Compression

Use gzip or brotli middleware, ETags, Cache-Control headers, and payload size budgets.

7 min readBuilding Backend ApplicationsBuild

Why Compress

Compression reduces response size by 60-90%. For a JSON API returning 10KB responses, gzip reduces this to 2KB. This reduces bandwidth costs, improves latency, and saves client battery life.

Gzip Middleware

Gogzip-compression-middleware.go

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Check Accept-Encoding before compressing. Only compress if the client supports gzip. Set Content-Encoding: gzip in the response header.

Brotli

Brotli achieves 15-25% better compression than gzip. It is supported by all modern browsers. Use it for static assets and API responses. The compression is slower but the bandwidth savings are significant.

Gocontent-negotiation-for-compression.go

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Negotiate the best compression algorithm. Prefer brotli over gzip. Fall back to no compression if the client does not support either.

ETags

Goetag-middleware.go

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ETags let the client cache responses. On subsequent requests, the client sends If-None-Match. If the ETag matches, return 304 Not Modified with no body. This saves bandwidth and improves latency.

Cache-Control

Gocache-control-headers.go

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API responses should not be cached by browsers. Static assets can be cached aggressively with content hashing. HTML pages get short caches with stale-while-revalidate.

Payload Size Budgets

Single resource: Under 10KB.
List response: Under 100KB with pagination.
File upload: Enforce max size with http.MaxBytesReader.
File download: Stream large files with chunked transfer.

Skip compression for small responses

Responses under 1KB are not worth compressing. The overhead of compression outweighs the savings. Set a minimum size threshold in your compression middleware.

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