PageSpeed Insights API review
Best free performance data
The PageSpeed Insights API runs Lighthouse against any public URL and returns the result as JSON, along with real-world Core Web Vitals from the Chrome UX Report where Google has enough traffic data for that page. It costs nothing.
The distinction between the two datasets matters. Lighthouse scores are lab results from a simulated environment and are useful for catching regressions. CrUX field data is what real Chrome users experienced, and it is what actually feeds Google's page experience signals.
Who PageSpeed Insights API is for
Any team that wants performance monitoring without paying for a synthetic monitoring product. It is the standard building block for automated site health dashboards and CI performance gates.
Strengths and limits
What it does well
- Free with a genuinely usable quota of 25,000 requests a day.
- Returns both lab and field data in one response, which few paid tools bother to separate as clearly.
- The same engine behind the public PageSpeed Insights tool, so the numbers match what a client sees when they check.
- Trivial to automate. One GET request per URL, no auth required for light use.
Where it falls short
- Field data only exists for URLs with enough Chrome traffic, so most pages on most sites return lab data only.
- Lighthouse scores are noisy between runs. Trend them over time rather than treating a single result as a fact.
- Rate limited to 100 queries per 100 seconds, and there is no way to pay for more.
PageSpeed Insights API pricing
Free, with no paid tier and no way to purchase additional quota. The limits are 25,000 requests a day and 100 queries per 100 seconds.
The practical constraint is the per-100-second rate rather than the daily cap. Auditing a large site means queueing requests with a delay rather than firing them in parallel, which is worth building in from the start.
Rate limits and quotas
- 25,000 requests per day per project.
- 100 queries per 100 seconds.
- No paid tier exists to raise the quota.
- An API key is optional for light use but recommended for anything automated.
Verdict
Free, authoritative and easy to automate, which makes it the obvious foundation for any performance monitoring you build. Pair it with Search Console and you have credible technical SEO reporting without spending anything. Just remember to trend Lighthouse scores rather than trusting a single run.
PageSpeed Insights API FAQ
Is the PageSpeed Insights API free?
Yes, entirely, with no paid tier. Limits are 25,000 requests per day and 100 queries per 100 seconds, and there is no way to purchase more.Do I need an API key?
Not for light use, but it is recommended for anything automated. Without a key you are rate limited more aggressively and share quota with other anonymous callers.What is the difference between lab and field data?
Lab data is a Lighthouse run in a simulated environment, useful for catching regressions. Field data comes from the Chrome UX Report and reflects what real users experienced, which is what feeds Google's page experience signals.Why is field data missing for some pages?
CrUX only reports on URLs with enough Chrome traffic to be statistically meaningful and to preserve anonymity. Most pages on most sites will return lab data only, with field data available at origin level instead.How do I audit a large site with this API?
Queue the requests with a delay rather than firing in parallel. The binding limit is 100 queries per 100 seconds, not the daily cap, so a large crawl needs pacing built in from the start.
Other providers worth a look
This is an independent review. We have no affiliate relationship with PageSpeed Insights API, earn nothing if you sign up, and no provider pays for placement in the directory. Prices were read from the vendor's own pages in August 2026 and change without notice.