SplitSignalBot
Semrush's other crawler.
Quick answer
SplitSignalBot is the crawler behind Semrush's SplitSignal tool, which lets a site owner create and run SEO A/B tests directly on their own website. It's a separate Semrush bot from SemrushBot and SiteAuditBot, each one tied to a different Semrush product and controlled independently in robots.txt.
What it does
SplitSignalBot supports Semrush's SplitSignal product, which site owners use to run structured SEO A/B tests on their own pages, comparing variations to see which performs better in search. Because this crawl is tied to a test a site owner set up themselves through Semrush, SplitSignalBot's activity is generally driven by that owner's own usage of the tool rather than by Semrush collecting data independently the way SemrushBot does for its backlink and keyword databases. It follows robots.txt rules, and Semrush documents SplitSignalBot's current user agent format on its own bot page rather than publishing a fixed string here, since the format can be checked there directly. Disallowing SplitSignalBot specifically only affects this one Semrush product, leaving SemrushBot and other Semrush bots unaffected unless they're also addressed.
Facts
Operator
Semrush
Robots token
SplitSignalBot
User agent string(s)
- (see semrush.com/bot/ for current User-Agent format)
Purpose
Other
Respects robots.txt
Yes
From Semrush's documentation, checked Oct 2026.
Should you block it?
SplitSignalBot isn't a search engine or AI answer crawler, so the decision here isn't about search ranking or AI visibility; it's about whether a site wants to use Semrush's SplitSignal tool to run its own SEO A/B tests. For a site actively using SplitSignal, blocking this bot would stop the tool from crawling the pages it needs to run those tests, breaking the workflow the site set up on purpose. For a site not using SplitSignal, allowing or blocking SplitSignalBot makes little practical difference, since its crawl activity is tied to tests a site owner configures rather than to independent, ongoing data collection the way SemrushBot's broader crawling works. A site mainly concerned about unwanted crawl load from third-party SEO tools in general would consider blocking all of Semrush's bots, including this one, rather than treating SplitSignalBot as a special case.
How to block it
Add this to robots.txt to block SplitSignalBot from crawling any page: User-agent: SplitSignalBot Disallow: / This only affects Semrush's SplitSignal tool; SemrushBot and other Semrush bots need their own rules if a site wants to block those too.
Frequently asked questions
What does SplitSignalBot actually do?
Semrush documents SplitSignalBot as the crawler used by its SplitSignal tool to create SEO A/B tests on a website.
Is SplitSignalBot the same as SemrushBot?
No. Semrush operates separate bots for different products. SplitSignalBot is tied specifically to the SplitSignal A/B testing tool.
Does blocking SplitSignalBot affect my search ranking?
No. It's an SEO testing tool crawler, not a search engine crawler, so it has no direct effect on search rankings.
Related
- AI crawler directory — every AI crawler's robots.txt token, purpose and facts in one place.
- Free AI crawler checker — check which AI crawlers a domain's robots.txt actually allows or blocks.
- Glossary — definitions of the AI-visibility terms that come up alongside crawler behavior.
Sources
- SplitSignalBot is used by Semrush's SplitSignal tool to create SEO A/B tests on a website. Source: https://www.semrush.com/bot/ (checked Oct 2026)
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