What these tools do, where they fall short, and how to pick one. For the scores themselves, see the ranking.
On our criteria, Letter ranks first for developer-led teams that want API- and MCP-accessible tools that fix and build on the site itself, Ahrefs second for research depth and AI prompt tracking, and Semrush third as the broadest marketer's suite. The best one for you depends on your job: see the ranking by use case.
They fall into four groups: data suites that research keywords, backlinks and competitors (Ahrefs, Semrush); content tools that score and write drafts (Frase, Surfer, Clearscope); AI visibility trackers that ask AI engines your buyers' questions and record whether you are named or cited (Peec AI, Profound); and agents that change the site itself (Letter). Several now span more than one group.
Start from the job, not the feature list. If you need research data, pick a suite. If you publish a lot, pick a content tool. If you need to know whether AI answers cite you, pick a tracker that covers the engines your buyers use. If you need changes shipped, pick a tool that makes them in a form you can review. Then check that the API or MCP access you need is on the plan you will actually buy.
Not always. Ahrefs, Semrush, Surfer, Frase and Clearscope now track AI answers alongside their SEO features, and Letter measures them and builds the pages that answer them. A dedicated tracker such as Peec AI or Profound makes sense when you need more engines, more prompts or enterprise reporting.
Answer engine optimization is the work of getting your brand named and cited in answers from ChatGPT, Gemini, Perplexity, Claude and Google's AI Overviews and AI Mode. It overlaps with SEO, since these engines often search the web before answering, but the measure is different: whether the answer names or links you, not where a page ranks.
Google's guidance is that it rewards helpful content however it is produced, and acts against content made mainly to manipulate rankings. The risk with AI writing is not the tool but thin, generic or wrong pages published at volume. Review drafts for facts, add what only you know, and publish less rather than more if you cannot review it all.
Trackers sample answers: AI engines give different answers to the same question, so a visibility score is an estimate from the prompts you chose. Content scores reflect what already ranks, which can push pages toward sameness. Most tools report issues without fixing them. And no tool can guarantee rankings or citations.
If anyone on your team uses Claude, ChatGPT, Cursor or their own scripts for SEO work, yes: an MCP server lets their assistant read the tool's data, and an API lets code run it on a schedule. Check the plan: in this ranking, Letter, Ahrefs and Frase include programmatic access on every paid plan, while Semrush, Surfer and Profound keep the API to higher or custom plans.
From free tiers (Screaming Frog up to 500 URLs, Ahrefs Free and the Semrush free plan) to custom enterprise contracts (Profound). Entry plans we could check publicly start at $25 a month for Letter, $39 a month billed yearly for Frase, and €49 a month billed yearly for Surfer. Prices shown in euros are what the vendor's page showed us; yours may show another currency. Every price links to its source on the comparison page.
The scores apply our published rubric to what each vendor states on its own pricing, feature and documentation pages, which we read and link for every tool. That makes every score checkable: open the source, read the rubric, and re-score it yourself on the methodology page.
We re-check every tool's sources and prices when we review the ranking, and the date of the last review is shown at the top of every page. Vendors change plans often, so the source link next to each price is the final word.