What is Prerender?
Prerender is a web crawler that pre-renders Single Page Applications (SPAs) into static HTML to improve SEO visibility for JavaScript-heavy websites and search engine indexing. Agent Analytics can track when it visits your website.
Overview
| Operated By | Prerender |
| Source | Official Website |
| Expected To Follow Robots.txt | Yes |
| Insights Last Updated | July 12, 2026 |
Category
Expected Behavior
Prerender maps sites the way its customers' SEO tools need, following internal links to build a full picture of structure, content, and ranking signals. Expect thorough crawls rather than spot checks, with frequency rising when your site or your competitors are actively monitored in its tools.
Prerender's User Agent
| User Agent | Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) HeadlessChrome/89.0.4389.82 Safari/537.36 Prerender (+https://github.com/prerender/prerender) |
How To Block Prerender With Robots.txt
Add this rule to your robots.txt file to block Prerender from accessing your entire website, or use Automatic Robots.txt to block all SEO crawlers at once. You can customize which pages are blocked by swapping out / for a different path.
User-agent: Prerender # https://knownagents.com/agents/prerender
Disallow: /Global Insights for Prerender
As of July 12, 2026, this data reflects agent visits measured across thousands of websites using Agent Analytics, combined with daily scans of the world's top 1000 websites and their robots.txt files.
Robots.txt Blocked Percentage
Country of Origin
Robots.txt Blocking Trend
0% of top websites block Prerender in their robots.txt files.
Overall SEO Crawler Traffic
3.2% of all web traffic came from SEO crawlers.
Frequently Asked Questions
Should I Block Prerender?
Only if you want your own pages and outbound links out of those tools. Prerender collects the ranking and backlink data behind SEO tools, likely including ones you or your agency use, and it does not change how search engines rank you. Blocking it will not hide your backlink profile either, because backlinks are discovered on the sites that link to you. Almost none of the top websites we track have robots.txt rules for Prerender right now.
Does Prerender Follow Robots.txt Rules?
Yes. Prerender is expected to follow robots.txt rules, so a disallow rule is the right first move. Automatic Robots.txt adds and maintains that rule for you, and Agent Analytics confirms Prerender actually follows it.
Does Prerender Access Private Content?
Login walls stop it. Prerender analyzes public pages for rankings, links, and site structure.
Why Is Prerender Visiting My Website?
Your domain shows up in the ranking, backlink, and competitor data Prerender's operator sells. If anyone tracks your site or your competitors in an SEO tool, Prerender visits you.
How Can I Tell if Prerender Is Visiting My Website?
Agent Analytics tracks Prerender visits in real time alongside every other known AI agent, crawler, and scraper. You can also check your server logs for requests whose user agent string contains "Prerender". Look for full site crawls that follow your internal links. Keep in mind that Prerender doesn't publish a verification method, so any client can claim its user agent string and a log match is a hint rather than proof.