Semrush suits small businesses, freelancers and agencies doing SEO day to day, with keyword research, rank tracking, site audits and AI visibility tracking, and a Free plan to try it. Similarweb suits marketers and researchers who need market, traffic and competitor intelligence across web, apps and ads, with free tools and a trial. Pick on whether you're improving your own site or sizing up a market.
Both tools will show you a competitor's traffic, so people treat them as interchangeable. They aren't. Semrush is built around improving your own visibility in search and AI answers. Similarweb is built around understanding markets, audiences and competitors across many channels.
Similarweb and Semrush in one table
| Similarweb | Semrush | |
|---|---|---|
| Built for | Digital market and competitor intelligence | SEO and AI search visibility |
| Free option | Free tools (Website Traffic Checker, App Analytics, Keyword Tool) and a free trial | Free plan: 1 demo project, 10 reports a day |
| Card to start free | Not stated | No credit card required |
| SEO tools | Keyword research, keyword gap, rank tracker, SERP analysis | Keyword research, Position Tracking, Site Audit, competitor analysis |
| AI search | AI traffic trends, AI brand visibility, prompt analysis | AI visibility reports, AI sentiment, custom prompt monitoring |
| Ads data | Search ads, display and social ads | A separate Advertising toolkit on the plans page |
| History | Up to 37 months, daily data | Historical data from higher SEO plans |
| Countries | 100+ country-level coverage | Multi-location tracking on higher plans |
| AI assistant access | AI Studio and an MCP | Semrush MCP for AI assistants |
What Semrush is built to do
Semrush's plans page frames everything around visibility. The entry SEO plan covers 5 websites and 500 keywords tracked daily, with keyword research, competitor analysis, Position Tracking and Site Audit, plus AI visibility reports and sentiment monitoring. Higher plans add historical data, content optimisation, cannibalisation analysis and multi-location tracking.
- Daily rank tracking for your own keywords.
- Site Audit to catch technical problems.
- AI visibility tracking for prompts you choose.
What Similarweb is built to do
Similarweb's plans page groups its tools into suites: Competitive Intel, Strategic SEO, Ads Intel and Gen AI Intel. You get demand analysis, segment and page-level insights, search and display ad analysis, and AI brand visibility, with up to 37 months of history at daily level across 100+ countries. AI Studio answers questions in plain language.
- Market sizing and competitor benchmarking.
- Ad intelligence across search, display and social.
- Custom data feeds and APIs for larger teams.
Getting the data into your own tools
Semrush offers an MCP that brings its traffic, visibility and market data into AI assistants, which suits a solo marketer who already works in ChatGPT or Claude. Similarweb's plans page lists real-time and bulk APIs, BI tool integrations, custom data feeds, connections to Snowflake and AWS, and an MCP for AI workflows. That's a sign of who each one is built for: Semrush for the person doing the work, Similarweb for the team feeding a dashboard.
How far the free options go
Semrush has a Free plan with no card: 1 demo project and 10 reports a day across its core tools, which is enough to learn the interface and run a few checks. Similarweb's route in is different: free tools such as its Website Traffic Checker, plus a free trial and self-service packages for individuals and small teams, with business packages arranged through sales. If you want to keep using something at no charge, Semrush's Free plan and Similarweb's free checkers are the two to bookmark.
If competitor research is your main job, my guide to competitor keyword research for your niche shows the method behind both tools.
Which team suits which tool
A small business, freelancer or agency doing SEO week in, week out will get more from Semrush, because rank tracking and site audits are the daily work. A marketing lead, investor or analyst asking how big a market is, where competitors get their traffic and which ads they run will get more from Similarweb. To see how Semrush positions itself, read my take on Semrush's marketing strategy.
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My advice on Similarweb or Semrush
Write down the one question you'll ask most often. 'Why isn't my page ranking?' points to Semrush. 'How is this competitor growing?' points to Similarweb. Use the free option for that exact question for a week, and you'll know which one earns a place in your stack.
Do you make an SEO, analytics or research tool? Tool makers can ask to be considered for a featured place in comparisons like this one.
Frequently asked questions
Is there a free version of Semrush?
Yes. Semrush's Free plan needs no credit card and includes 1 demo project and 10 reports a day across its core tools.
Is Similarweb free?
Similarweb offers free tools such as its Website Traffic Checker, App Analytics and Keyword Tool, plus a free trial; business packages are arranged with its sales team.
Does Semrush track AI search?
Yes. Its SEO plans include AI visibility reports, AI sentiment monitoring and tracking for custom prompts.
How much history does Similarweb show?
Its plans page lists up to 37 months of data, with daily-level insights and coverage for 100+ countries.
