Similar sites extension or keyword lookup: which belongs in your workflow

A similar sites extension is the obvious thing to install when you keep asking "what else is like this page?" It lives in the toolbar and answers in one click. A keyword overlap lookup takes a minute longer and costs credits, but it answers a narrower question with numbers. For developers who look at rival products and docs sites all day, the two do different jobs. Here is how they compare, and which one earns a place in your workflow.

The two contenders

SimilarSites browser extension. A free Chrome extension from SimilarGroup, whose footer also lists SimilarWeb and SimilarTech among its tools. You open a site, click the icon, and get a list of related sites. Its home page promises to "instantly find similar sites". We did not test how it builds the list, so treat its idea of "similar" as its own.

seogeoaeo.ai Competitor Finder. A web tool that you can also call from an MCP client or over REST. You enter any public domain and a Google country. It compares that domain's ranking keywords with every other site and returns up to 30 domains that share the most, with numbers for each.

Side by side

When the extension is enough

You are browsing, you land on an interesting tool, and you want three more like it to try this afternoon. You do not care why they are similar, only that they are. A free toolbar button fits that moment and nothing else needs to.

When the lookup wins

You are planning docs, a changelog page or a blog, and you need to know which domains compete for the same searches as a rival. Here "similar" has to mean something you can measure, and the overlap share is the measure. A site where at least 5% of its keywords match the rival's is a close competitor. A huge general site that shares a few hundred keywords out of millions is not, and Competitor Finder sets those aside instead of putting them at the top.

You also get the output as data. From a terminal agent, one call returns rows you can drop into a CSV, diff next month, or feed into the next tool:

curl -X POST https://seogeoaeo.ai/api/v1/tools/competitor-finder/runs \
  -H "Authorization: Bearer $SEOGEOAEO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"input":{"url":"https://rival.dev","market":"us"}}'

Pass maxCredits with a call and the API refuses any run priced above it. That matters once an agent is looping.

A typical session

Say you maintain an open source CLI and a paid hosted version. You run the lookup on the best-known rival's domain, keep the close matches, and find two docs-heavy sites and one tutorial blog you had never heard of. Those are the pages taking the "how do I" searches your docs should answer. A toolbar list of lookalike products would not have shown you the blog at all.

What the lookup will not tell you

It only sees Google search. A dev tool that grows through word of mouth, conference talks or paid ads, and ranks for little, will not show up. The lookup covers the whole domain, so you cannot ask about one docs folder. Visits and keyword counts are estimates. A small domain may return few close matches, because the few terms it ranks for are mostly shared with large sites; run it on a bigger rival instead.

Cost check

Indie is $29 a month for 2,000 credits, about 52 Competitor Finder runs. Each tool shows its price before running, failed runs are refunded, and monthly credits reset at renewal. If you only need a list of lookalikes once in a while, the free extension is the cheaper habit. If the list feeds a plan, the paid lookup gives you something to act on.

The pick

Keep the extension for casual browsing if you like it. For anything you will base work on, use Competitor Finder on seogeoaeo.ai, then take the close matches into Competitor Keywords (35 credits) to see what brings them traffic. The MCP setup notes cover connecting it to Claude Code or Cursor.

One honest caveat: if what you want is to watch a rival's rankings change day by day, neither option does that. A suite with a rank tracker is the right tool for that job.