{
  "schemaVersion": "crawler-atlas-1",
  "atlasVersion": "atlas-2026-07-28-v1",
  "canonical": "/atlas/compression",
  "title": "Response compression",
  "category": {
    "slug": "http",
    "title": "HTTP behavior and efficiency"
  },
  "definition": "Compression reduces transferred bytes when the client advertises a supported content encoding.",
  "mechanism": "The server selects gzip, Brotli, or identity based on Accept-Encoding and should vary caches on that decision.",
  "validation": "Measure compressed and uncompressed sizes, Content-Encoding, Vary, and total latency for representative HTML, JSON, CSS, and script bodies.",
  "commonFailure": "Precompressed content with an incorrect Content-Length or missing Vary header can produce corrupted responses or cache confusion.",
  "related": [
    "/atlas/content-negotiation",
    "/atlas/cache-validators"
  ],
  "modified": "2026-07-28"
}