Facts checked September 14, 2026

Foglift vs PageSpeed Insights

PageSpeed Insights is the stronger specialist for performance, with Lighthouse 13 lab diagnostics and eligible 28-day CrUX field data. Foglift is the stronger operating layer when you need performance inside a five-dimension Technical Audit, separate AI Readiness, and recurring AI answer monitoring. Unlimited single-page audits cost $0; five-engine monitoring and developer access start at $49 per month.

The short answer

Choose Foglift for the whole improvement loop

Run a free Technical Audit, inspect eight AI Readiness dimensions, monitor buyer questions across five AI engines, rank the next fixes, and keep crawler requests and human AI referrals separate. Launch adds the REST API, CLI, MCP, webhooks, batch scans, and full-site audits at $49 per month.

Choose PageSpeed Insights for performance depth

Inspect the full Lighthouse report for one mobile or desktop URL. When Chrome has enough eligible traffic, compare the simulated run with 28 days of real-user LCP, INP, CLS, and FCP distributions at the URL or origin level.

Feature and evidence comparison

Decision	Foglift	PageSpeed Insights
Starting point	Unlimited single-page Technical Audits at $0; Launch monitoring at $49/mo	Free web report; API key optional for testing and recommended for frequent automated use
Primary job	Find technical and AI-readiness issues, monitor AI answers, rank fixes, and measure crawler and referral outcomes	Diagnose page performance with Lighthouse lab data and eligible CrUX field data
Technical Audit scope	SEO, performance, security, accessibility, and a separate AI Readiness result	Lighthouse performance, accessibility, best-practices, and SEO categories
Performance evidence	Uses PageSpeed v5 category scores when available and adds selected diagnostics plus local checks	Complete Lighthouse diagnostics for mobile and desktop
Real-user field data	Available in the free Page Speed Test when Google has enough CrUX coverage	Native 28-day CrUX distributions at URL level, with origin fallback when eligible
AI Readiness	Eight structural dimensions, including crawler access, entity identity, FAQs, depth, and citation formatting	No dedicated AI-readiness assessment
AI answer monitoring	Active-use weekly Perplexity on Free; five engines from Launch	No tracked prompts, brand mentions, citations, sentiment, or share of voice
Crawler and referral evidence	Sensor separates crawler requests from human visits arriving through AI answer links	Outside the PageSpeed performance workflow
Recommendations	Evidence-ranked technical, content, authority, and comparison actions with verification	Lighthouse performance opportunities and diagnostics
Full-site coverage	Launch+: up to 100 selected pages, automatic weekly coverage, and seven-day manual availability	One tested URL at a time; CrUX may summarize the origin when URL data is insufficient
Saved reporting	Shareable Technical Audit result and PDF export	Shareable report snapshots remain available for up to 30 days
Developer workflow	REST API, CLI, hosted MCP, webhooks, and batch scanning start on Launch	PageSpeed Insights API v5 and Lighthouse CLI, Node, and CI options

How the tools work together

A Foglift Technical Audit requests PageSpeed Insights v5 when Google is available. It consumes the Lighthouse category scores for performance, accessibility, and SEO, then combines them with local page analysis and security-header checks. Google remains the source of the Lighthouse result.

The products diverge after that shared input. PageSpeed Insights keeps the complete performance trace, opportunities, runtime context, and eligible CrUX distributions. Foglift places the selected performance evidence beside SEO, security, accessibility, and a separate eight-dimension AI Readiness result. Its monitoring layer then records what AI engines answered, cited, and recommended.

Use field data for the outcome and lab data for diagnosis. A strong Lighthouse run does not prove that real users meet Core Web Vitals, and a crawler fetch does not prove that an AI answer cited the page. The two distinctions protect the same thing: evidence from one stage cannot stand in for another.

What PageSpeed Insights measures in 2026

Lighthouse 13 lab run: A simulated mobile or desktop load supplies performance diagnostics plus accessibility, best-practices, and SEO audits. Google deployed Lighthouse 13 to PageSpeed Insights on October 20, 2025.
28-day CrUX field window: Eligible Chrome traffic supplies real-user distributions for LCP, INP, CLS, and FCP. PSI reports the 75th percentile and can fall back from the URL to the origin when coverage is insufficient.
A changing API boundary: The v5 API accepts direct requests and recommends an API key for frequent automation. Google says CrUX field data will leave the PageSpeed API, with the CrUX APIs becoming the dedicated programmatic source.

What Foglift adds

One five-dimension report

SEO, performance, security, and accessibility roll into Site Technical Health. AI Readiness remains a separate reported value, so a strong technical score cannot hide weak answer-ready structure.

Eight AI Readiness dimensions

Structured-data richness, heading clarity, FAQ quality, entity identity, content depth, citation formatting, topical authority, and AI crawler access stay inspectable as page-level evidence.

Answers across five engines

Launch monitors ChatGPT, Claude, Perplexity, Gemini, and Google AI Overview. Mentions, provider-returned citations, sentiment, competitors, and share of voice remain answer evidence rather than audit predictions.

Crawler and human outcomes

Sensor logs recognized crawler requests by purpose and records recognized human visits from AI answer links. Fetches, citations, and referrals remain separate measurements.

A ranked fix queue

Recommendations combine audit, answer, source, competitor, Search Console, crawler, and referral evidence. Each action carries a target and verification boundary instead of another disconnected score.

Developer access from Launch

The $49 monthly Launch plan adds REST API keys, CLI and MCP access, webhooks, batch scanning, daily five-engine monitoring, and weekly full-site audits of up to 100 selected pages.

A practical two-tool workflow

01Start broad. Run a free Foglift Technical Audit to place performance beside SEO, security, accessibility, and AI Readiness.
02Debug performance in Google. Open PageSpeed Insights for the complete Lighthouse report, mobile and desktop comparison, and eligible CrUX field distributions.
03Fix the right layer. Use Lighthouse opportunities for runtime work and the Technical Audit findings for page structure, crawlability, security, and answer extraction work.
04Verify with the matching evidence. Rerun the lab audit after a release, wait for the CrUX window to move, and use recurring AI Visibility Checks for answer-level changes.

Primary sources and product specifications

Google for Developers: About PageSpeed Insights for lab data, the trailing 28-day CrUX window, URL-to-origin fallback, 75th-percentile reporting, and Core Web Vitals.
Google for Developers: PageSpeed Insights release notes for Lighthouse 13 and the 30-day shareable-report boundary.
Google for Developers: PageSpeed Insights API for v5 access, API-key guidance, and the announced move of field data to the CrUX APIs.
Foglift Technical Audit specification for the single-page, full-site, report, PDF, plan, and scoring boundaries.
Foglift developer platform for the REST API, CLI, MCP, webhook, and batch-scanning surface.

Start with the wider evidence set

Run one public URL through all five Technical Audit dimensions. Keep PageSpeed Insights open for the deeper performance trace when the report points there.

Run a Free Technical Audit Open PageSpeed Insights

Related comparisons and guides

Foglift vs Lighthouse →Run a Page Speed Test →Website Health Check →Foglift vs Screaming Frog →Technical Audit Product →Developer API, CLI, and MCP →

Frequently asked questions

What is the main difference between Foglift and PageSpeed Insights?

PageSpeed Insights specializes in page performance. It combines Lighthouse lab diagnostics with eligible Chrome User Experience Report field data. Foglift uses PageSpeed category scores inside a broader Technical Audit, then adds separate AI Readiness, AI answer monitoring, crawler and referral evidence, recommendations, and developer workflows.

Is Foglift or PageSpeed Insights better for Core Web Vitals?

Choose PageSpeed Insights for the deepest Core Web Vitals investigation. Its native report separates a controlled Lighthouse run from 28-day CrUX field distributions and can fall back from URL to origin data. Foglift is the better fit when the performance result needs to sit beside SEO, security, accessibility, AI Readiness, and ongoing AI Visibility evidence.

Are Foglift and PageSpeed Insights both free?

Yes, for different jobs. Foglift offers unlimited single-page Technical Audits at $0 without a credit card, plus active-use weekly Perplexity monitoring after signup. PageSpeed Insights offers free mobile and desktop performance reports. Foglift Launch costs $49 per month and adds five-engine monitoring, full-site Technical Audits, REST API, CLI, MCP, webhooks, and batch scanning.

Does Foglift replace PageSpeed Insights?

Use both when performance is material. Start with Foglift to place performance inside the wider site and AI-search workflow. Open PageSpeed Insights when you need complete Lighthouse detail, lab-run context, or native CrUX distributions. Foglift also provides a free Page Speed Test that can show lab metrics and eligible CrUX data.

Can PageSpeed Insights measure AI search visibility?

PageSpeed Insights does not run buyer questions across AI engines or report brand mentions, answer citations, sentiment, competitors, crawler requests, or AI referrals. Foglift tracks those answer-level outcomes across ChatGPT, Claude, Perplexity, Gemini, and Google AI Overview on Launch and higher plans.

When should I choose Foglift over PageSpeed Insights?

Choose Foglift when the decision spans more than page speed: technical health, eight-dimension AI Readiness, recurring answer monitoring, source and competitor evidence, prioritized fixes, crawler activity, human AI referrals, or API, CLI, and MCP access. Choose PageSpeed Insights when the immediate job is a detailed performance investigation for one URL.

How we compare

These sources explain why the comparison separates AI-answer visibility from search rank, checks results by engine, and dates product evidence. They do not determine feature or pricing verdicts and do not establish universal ranking factors.

Aggarwal et al., “GEO: Generative Engine Optimization,” KDD 2024. The 10,000-query GEO-Bench found that tested textual interventions including citations, quotations, and statistics could improve source visibility by up to 40 percent, with results varying by domain. The study did not test JSON-LD or Google AI Overviews.
SE Ranking, “What actually drives AI citations,” current first-party study summary. The analysis covers 129,000 domains and 216,000 pages for ChatGPT plus 295,000 domains and 2.3 million pages for AI Mode. Referring domains ranked first for ChatGPT; organic traffic ranked first for AI Mode.
Chatoptic, “SEO ≠ GEO: Only 62% Overlap Between Google Ranking and ChatGPT Visibility,” 2025. Across 1,000 queries, 15 brands, and five categories, Google top-10 position had a 0.034 correlation with ChatGPT mention order when browsing was on. The study measured mentions and order, not URL citations.
Ahrefs, “AI Assistants Prefer to Cite Fresher Content,” 2025. Across 16.975 million cited URLs, AI-assistant citations skewed newer than organic results on average, while Google AI Overviews did not. Treat recency as an observational signal, not a causal score.

Feature and pricing data is verified against each tool's public website before comparison pages are refreshed.