perf.ttfb-slow

What to change

A finding of this rule on a page carries the exact edits for that page: the markup it quotes, and what to write instead.

When it runs

Runs with --lighthouse, on the command or the local server. A warning is a problem that costs a page ranking, clicks or citations. Each finding takes 5 points off the page's score.

The severity here is the rule's usual one: a finding can be raised or lowered when the page gives a reason.

Run it, or skip it

Check a page for this rule alone, after a fix for instance:

npx @rivi-software/agentic-seo-check audit https://example.com --lighthouse --rule perf.ttfb-slow

Or from an assistant, with the MCP tool seo_audit_page:

{
  "url": "https://example.com",
  "lighthouse": true,
  "rules": [
    "perf.ttfb-slow"
  ]
}

To leave it out of an audit, pass --disable perf.ttfb-slow on the command, or disableRules: ["perf.ttfb-slow"] to a tool.

• Warningperf.lcp-slowLargest Contentful Paint above 2.5 s (poor above 4 s). Lab measurement from Lighthouse.
• Warningperf.cls-highCumulative Layout Shift above 0.1 (poor above 0.25).
• Warningperf.tbt-highTotal Blocking Time above 200 ms (poor above 600 ms). Lab proxy for Interaction to Next Paint.
• Infoperf.fcp-slowFirst Contentful Paint above 1.8 s (poor above 3 s).
• Warningperf.score-lowLighthouse performance score below 50.
• Infoperf.opportunityA Lighthouse opportunity with measurable estimated savings.
• Warninglighthouse.seo-audit-failedA Lighthouse SEO audit failed (rendered-DOM checks such as crawlable anchors, robots.txt validity).
• Infolighthouse.agentic-audit-failedA Lighthouse agentic-browsing audit failed (llms.txt, accessibility tree quality, WebMCP). Experimental.