Monitoring

    Gzip / Brotli compression check

    Verifies your server compresses HTML, CSS, JS, and JSON responses — up to 80% payload reduction that costs nothing to enable.

    Updated 2026-07-10
    1 min read
    compression
    gzip
    brotli

    Quick answer#

    We send Accept-Encoding: br, gzip, deflate and check which encoding your server picks. Uncompressed text responses fail.

    What it checks#

  1. HTML, CSS, JS, JSON, SVG served compressed
  2. Brotli preferred (bonus)
  3. Compression ratio ≥60%
  4. Compression NOT applied to images/video (which are already compressed)

    5. Where to find it in Lemwatch#

    Site details → Performance → Compression.

    How to fix#

  5. Enable gzip in your web server config.
  6. Add Brotli for another 15-20% savings.
  7. Set compression on text/* and application/json, javascript, xml.
  8. Re-run the check.

    9. FAQ#

    Should I compress at the CDN or origin?#

    CDN — cached compressed variants are cheapest.

    Is Brotli safe?#

    Yes — supported by every modern browser since 2017.

    Related#

  9. Performance budgets
  10. Core Web Vitals
  11. Cache-Control header check
    12. Was this article helpful?

    Previous

    HTTP/2 & HTTP/3 support check

    Next

    Cache-Control header check

    Related Articles

    Setting Performance Budgets

    Set thresholds and get alerted when metrics exceed your limits.

    Core Web Vitals Explained

    Understanding LCP, CLS, INP and how to improve them.

    Cache-Control header check

    Grades your Cache-Control headers on static assets, HTML, and API responses — bad caching is a leading hidden cause of slow LCP.

    How Health Scores Work

    Deep dive into how LemWatch calculates and attributes health scores.

    Back to Help Center