Lighthouse — alert on a perf-score drop between releases
After a release Lighthouse perf score drops from 90 to 65 (new lib without code-split, or un-minified bundle). You only learn when RUM starts showing LCP > 4 s.
Recipe
#!/usr/bin/env bash
# /etc/cron.d/lighthouse-drop
# 0 */1 * * * root /opt/lighthouse-drop.sh
URL=${URL:-https://example.com}
THRESH=${THRESH:-80} # alert below score N
# Headless lighthouse, JSON output
SCORE=$(lighthouse "$URL" \
--quiet --chrome-flags='--headless' \
--output=json --output-path=stdout 2>/dev/null \
| jq '.categories.performance.score * 100 | floor')
if [ "${SCORE:-100}" -lt "$THRESH" ]; then
curl -fsS "$HEARTBEAT_URL" --data "perf_score=$SCORE,threshold=$THRESH,url=$URL"
exit 2
fi
echo "OK (perf=$SCORE)"Same thing in Enterno.io
Use Enterno PageSpeed for score retention — you spot the day LCP jumped and tie it to a commit.
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