SpyFu suits businesses that mainly want to see what competitors do on Google, especially their Google Ads keywords and ad test history, plus their SEO keywords. Semrush suits businesses that want a full marketing toolkit: keyword research, site health, rank tracking, link research, content tools and now AI search visibility in one platform called Semrush One. If competitor research is the job, SpyFu is focused and simple; if you want one tool for most of your SEO, look at Semrush.
These two get compared because both started as competitor research tools. Today they've grown in different directions. SpyFu has stayed focused on competitors, keywords and Google Ads. Semrush has become a broad platform and now pitches itself on visibility in AI search too. I read SpyFu's home page and Semrush's home page.
SpyFu and Semrush at a glance
| SpyFu | Semrush | |
|---|---|---|
| Main focus | Competitor keywords for Google Ads and SEO | Unified SEO and AI search platform |
| Standout feature | Competitors' full Google Ads history | AI Visibility and prompt research |
| Data scale | 7.2 trillion results across 152 million domains | Not stated on the page I read |
| Other tools | PPC negative keywords, SEO research | Site health, rank tracking, link research, content |
| AI connections | Not stated on the page I read | Semrush MCP for AI assistants |
| Free option | Not stated: try it free | Not stated: start for free |
SpyFu's competitor ads history
SpyFu's home page says it indexes over 7.2 trillion results across 152 million domains, and its most distinctive feature is Google Ads history. You can browse a competitor's complete campaign history, see the results of every ad split test they've run, and spot the early keywords that didn't work out for them. If you run Google Ads, that saves you repeating a rival's failed tests, and it's the main reason people choose SpyFu.
Semrush One and AI search
Semrush now leads with Semrush One, which it calls the unified SEO and AI search solution. Alongside keyword research and competitor analysis, its page lists AI Visibility, prompt research, local SEO, market analysis, content creation, technical site health, digital PR, rank tracking, marketing reports, AI brand sentiment and link analysis. There's also a Semrush MCP connection, so you can bring its data into AI assistants. If you care about being mentioned by ChatGPT and other AI tools as well as ranking on Google, that's a real difference.
Questions to settle first
- Do you run Google Ads, or is your traffic mostly organic?
- Do you need site audits and rank tracking, or just competitor research?
- Do you want to track how AI assistants mention your brand?
- Who will use it, and how much time can they put into learning a bigger tool?
A focused tool you use every week is worth more than a big platform you open once a month. Before you choose, it helps to know how to do keyword research on competitors, and this look at Semrush's own marketing strategy shows how the company grew.
How to get value in your first week
- List your three closest competitors and the five searches you most want to win.
- With SpyFu, check which of those competitors' Google Ads keywords and ad tests have lasted longest.
- With Semrush, run a site health check on your own site and fix the top issues first.
- Check how AI assistants describe your brand in Semrush's AI Visibility tools.
- Pick one change to make this week and measure it against those five searches.
My advice on SpyFu or Semrush
If you run Google Ads and want to learn from your competitors, try SpyFu first, because its ads history is the quickest win. If you want one platform for SEO, site health and AI search visibility, trial Semrush One and run a full audit of your own site in week one. You can also use both, with Semrush for daily SEO work and SpyFu for ads research.
Do you make SEO or keyword research software? Tool makers can ask to be considered for a featured place in comparisons like this one.
Frequently asked questions
What is SpyFu best known for?
Competitor keyword research, especially a competitor's full Google Ads campaign history and ad test results.
Want AI doing the heavy lifting in your marketing?
I build the systems that handle the boring 80 percent, so you get your week back. Done properly, with the human kept in.
What is Semrush One?
Semrush describes Semrush One as its unified SEO and AI search solution, covering keyword research, site health, rank tracking and AI visibility.
Does Semrush track AI search?
Yes. Its home page lists AI Visibility, prompt research and AI brand sentiment, plus a Semrush MCP connection for AI assistants.
How much data does SpyFu have?
SpyFu says it indexes over 7.2 trillion results across 152 million domains.
Which is better for local businesses?
Semrush lists local SEO tools within Semrush One, while SpyFu focuses on competitor keywords and Google Ads research.
Can I use both?
Yes. Some marketers use Semrush for everyday SEO work and SpyFu for Google Ads competitor research.
