Ahrefs MCP vs Semrush MCP: which one to connect, what each costs, and how far the units go
Connecting Ahrefs or Semrush to an AI is like taking a taxi with the meter running, so it pays to know how each meter works.
A plain-text version of this site for AI assistants is at https://contengi.com/llms.txt, with the full product documentation in one file at https://contengi.com/llms-full.txt. Every page is also available as markdown by adding .md to its URL.
TL;DR
- Pick Ahrefs MCP for backlink and competitor work, and Semrush MCP if your team already lives in Semrush or needs paid search and traffic data in the same chat.
- Both are official remote servers you add to Claude or ChatGPT with a URL and a sign-in, and neither charges extra for the server itself, because every call spends API units from your plan.
- Ahrefs MCP works on Lite and up, with 200,000 API units a month on Lite (€119 a month on the pricing page), a minimum of 50 units per call, and 100 rows per request.
- Semrush MCP needs a qualifying plan, charges units per row returned, and puts traffic and market data behind a separate Trends API subscription.
- An agent asks more questions than a person, so set a monthly unit cap on day one and ask narrow questions.
Connecting Ahrefs or Semrush to an AI is like taking a taxi with the meter running. The ride is quick and comfortable, and every extra question the agent asks on your behalf ticks the meter over. Knowing how each meter works decides which one you should get into.
This post compares the two official servers on what they cover, what they cost, how far the units stretch, and how to set them up. For the full stack, including the free servers, start with the guide to SEO MCP servers in 2026.
Ahrefs MCP vs Semrush MCP at a glance
| Ahrefs MCP | Semrush MCP | |
|---|---|---|
| Server | Official, hosted, remote only | Official, remote |
| Plans with access | Lite and up | Qualifying paid plans, plus Trends API for traffic data |
| Entry price | €119 a month (Lite) | $199 a month (Starter) |
| Units included | 200,000 a month on Lite | 50,000 MCP units a month on Starter and Pro+ |
| How units are spent | At least 50 units per call, more for complex requests | Per row returned, priced by report type |
| Best at | Backlinks, referring domains, competitor pages | Keyword research, paid search, domain and traffic comparisons |
What does Ahrefs MCP give you?
Ahrefs MCP connects your AI assistant to the Ahrefs API through a hosted server available on paid plans from Lite upwards. You paste the connection URL into Claude, ChatGPT, Copilot Studio, n8n, or another supported client, approve access, and the connection syncs across your devices.
Lite includes 200,000 API units and 100 rows per request, Standard 800,000 units and 250 rows, and Advanced 2,000,000 units and 500 rows, and one API call costs a minimum of 50 units. So Lite buys up to 4,000 of the cheapest calls a month, fewer once the agent asks for big reports. Keys created through OAuth for MCP also default to a 200,000-unit monthly cap, which you can change.
Ahrefs no longer supports a local setup, only the remote server, and its terms don't allow you to call the MCP endpoint from your own scripts. If you want to build automations, the Ahrefs API is the supported route.
What does Semrush MCP give you?
Semrush MCP connects your AI assistant to live Semrush data for keyword targeting, domain audits, competitor and paid search tracking, and backlink research. It runs as a remote server with OAuth sign-in, so in Claude Code it's a single command and in Claude or ChatGPT it's a connector.
Plan access is where Semrush gets fiddly. Starter ($199 a month) and Pro+ ($299 a month) include 50,000 MCP API units, the entry SEO plan doesn't qualify, and Semrush charges units per row returned at the same rates as its API. At 10 units per organic keyword row, 50,000 units is about 5,000 rows a month. Traffic and market data need a Trends API subscription, which includes MCP access, and extra unit packages come in sizes from 2 million to 20 million.
Project data such as position tracking and site audits is read-only over MCP, so the AI can report on your setup but not change it.
Which one should you connect?
Connect the one you already pay for. Both servers do the job, and neither of them are cheap enough to justify a second subscription for MCP alone.
- Choose Ahrefs MCP if link building, broken backlinks, and competitor page analysis fill your week, or you want Brand Radar data on AI Overviews, which needs its own add-on.
- Choose Semrush MCP if you run paid search alongside SEO, need traffic estimates for competitors, or your agency already reports from Semrush.
- Choose neither if you pay for neither today. Pay-as-you-go data or your own Search Console will cover a small site, and there are cheaper SEO tools for small businesses for everything else.
The research behind this post ran on Google's own keyword and SERP data, pulled through Contengi's MCP, with no Ahrefs or Semrush units spent. One thing it surfaced: Google reads the bare query "seo mcp" as a general SEO search and fills page one with SEO starter guides. Branded searches such as "ahrefs mcp" leave no doubt about what the searcher wants, which is part of why this comparison exists.
How to keep the meter under control
- Set a unit cap before the first session. Ahrefs lets workspace admins change per-key limits, so give the MCP key its own ceiling.
- Ask for a number of rows. "Top 50 organic keywords for this domain in the UK" costs a fraction of "what does this site rank for?".
- Ask the AI what it requested. A follow-up such as "how many rows did that use?" shows you where the units went.
- Save your best prompts. Reusing a tested prompt is cheaper than letting the agent explore every week, and it fits neatly into an agentic SEO workflow.
- Turn findings into briefs straight away. Data you don't act on is units spent for nothing, so feed it into your SEO content briefs while it's fresh.
Frequently asked questions
Is Ahrefs MCP or Semrush MCP better?
Ahrefs MCP is stronger for backlink and competitor page analysis, and Semrush MCP is stronger for keyword research alongside paid search and traffic data. If you already pay for one, connect that one.
Does Ahrefs MCP cost extra?
No. The server is free on Lite and higher plans, and each call spends API units from your monthly allowance, starting at 200,000 units on Lite.
Which Semrush plans include MCP?
Starter and Pro+ include 50,000 MCP API units a month, the entry SEO plan doesn't qualify, and traffic data needs a Trends API subscription. Larger unit packages are sold separately.
Can I use Ahrefs MCP and Semrush MCP with Claude?
Yes. Both connect to Claude as remote servers with a URL and a sign-in, and both also work in ChatGPT and Claude Code.
Can I run Ahrefs MCP locally?
No. Ahrefs only supports its remote MCP server now, and calling the endpoint from your own scripts isn't permitted. Use the Ahrefs API for custom automations.