Rankfill

Competitor Website Research: Map Gaps, Then Fill Them

You publish something, wait three months, and watch it sit at position 34. Meanwhile, a competitor with a domain you've never heard of ranks #2 for the exact keyword you were targeting. You click through to their page. It's not even that good. So what are they doing that you're not?

Usually the answer isn't better writing or a smarter strategy. It's coverage. They've published pages across dozens of related topics, and their topical depth signals to search engines that they own the subject. You published one piece. They published forty.

Competitor website research is how you figure out what those forty pages are — and which ones you should build first.

What You're Actually Looking For

When most people say "competitor research," they mean looking at a rival's website and getting a general sense of what they do. That's not useful. What's useful is a specific list of keywords your competitors rank for that your site does not.

That gap is your opportunity. Every keyword on that list is a search query where a potential customer is going to someone else's site instead of yours — right now, today.

There are three layers to this:

1. Keywords they rank for that you don't target at all. These are complete blind spots. You have no page addressing this topic, no mention of this term.

2. Keywords they rank for where you have content but rank poorly. You're at position 28. They're at position 3. Your page exists but isn't competitive.

3. Keywords where neither of you rank well. These are often the most interesting — nobody has owned them yet, so the barrier to entry is lower.

Most of the work is in layer one. That's where the fastest wins live.

How to Do the Research

Start with the right competitors

Your SEO competitors aren't always your business competitors. A software company might compete in search with a media site that publishes comparison articles. A local plumber might lose search traffic to a home improvement blog.

Find your actual search competitors by taking 3-5 keywords you care about, running them in Google, and noting which domains appear repeatedly. Those are your real competitors for this exercise — not the companies you think of when someone says "the competition."

Pull their keyword data

You need a tool that shows you what a given domain ranks for. Ahrefs, Semrush, and Moz all have site explorer features that do this. Enter a competitor's domain and export their ranking keywords. You're looking for:

Do this for each competitor you identified. You'll end up with several spreadsheets.

Find the gaps

Now compare what they have to what you have. This is the content gap analysis step. Most tools have a built-in content gap feature — in Ahrefs it's literally called "Content Gap," in Semrush it's "Keyword Gap." You input your domain and your competitors' domains, and it returns keywords they rank for that you don't.

Export that list. Filter out irrelevant terms (brand names, geographies you don't serve, topics outside your scope). What remains is your opportunity set.

If you want to go deeper than what the major platforms offer, there are Screaming Frog alternatives for content gap analysis worth knowing about — some are lighter on budget while still surfacing structural gaps.

Prioritize ruthlessly

A content gap analysis often returns hundreds or thousands of keywords. You cannot write all of them, so you have to pick. The variables that matter:

A simple scoring approach: multiply relevance (1–3) by search volume, then divide by difficulty. Sort descending. The top of that list is where you start.

What to Do With the List

Group by topic cluster

Don't treat each keyword as a standalone article. Cluster related terms together — a pillar page covering the broad topic, with supporting pages going deeper on subtopics. This is how you build topical authority, which is what causes Google to start trusting your domain on a subject.

For example, if your gap analysis surfaces "project management software for small teams," "project management templates," "how to set up a project tracker," and "project management vs task management" — those belong in the same cluster, not four disconnected articles.

Build with intent in mind

Each keyword signals what the searcher wants. Some want a definition. Some are comparing products. Some are ready to buy. Before writing anything, Google the keyword yourself and look at the top 3 results. Are they blog posts? Landing pages? Listicles? That tells you what format Google thinks satisfies the intent — and you should match it.

For a deeper look at reading intent from search results and structuring content around it, how to analyze competitors and steal their keywords walks through this in practical detail.

Publish consistently

One article won't move the needle. What moves the needle is filling 20, 30, 50 gaps over a period of months. The sites that dominate a niche are the ones that systematically covered it — they didn't publish randomly, they executed a plan.

This is where most sites fail. The gap analysis happens, the spreadsheet gets made, and then life intervenes. The list sits. Nothing gets published. The competitor keeps ranking.

What Good Research Actually Produces

When done right, competitor website research gives you:

That last piece — the traffic estimate — matters more than people realize. It converts the research from an abstract exercise into a business case. "If we publish these 30 articles and rank for them at average positions, we'd add roughly X visits per month." That's how you justify the work to yourself or to anyone else funding it.

Tools like Rankfill automate this entire mapping process — identifying which competitors are in your space, scoring them, surfacing the keyword gaps, estimating traffic potential, and producing a full content plan — for sites that have the domain authority to compete but haven't yet published enough content to capture what's available.

For most sites, though, the manual process described above gets you 80% of the way there. The tools just make it faster and more complete.

The Trap to Avoid

Don't copy your competitors. That's not what this is.

The goal is to understand the full landscape of what searchers in your space are looking for, figure out which of those searches you're absent from, and then publish something genuinely useful on those topics. If you just reproduce what your competitor wrote, you won't outrank them — Google has been good at detecting thin, derivative content for years.

The gap tells you where to build. The quality of what you build determines whether it works.

For a full breakdown of what to examine when you pull up a competitor's site — structure, backlinks, content format, internal linking — competitor site analysis: what to look for and why covers the complete checklist.

Frequently Asked Questions

How many competitors should I analyze? Three to five is usually enough. More than that and the data becomes hard to act on. Pick the domains that repeatedly show up in the top results for your core keywords.

What if I don't have budget for Ahrefs or Semrush? Semrush has a free tier that allows limited keyword and domain lookups. Ubersuggest offers similar functionality at lower cost. You won't get the same depth, but you can still find meaningful gaps.

How long does it take to see results from content published after a gap analysis? Typically three to six months before pages gain meaningful traction, though lower-competition keywords in less saturated niches can rank faster. The timeline is why you start immediately — waiting costs you months.

My competitors have thousands of pages. Where do I even begin? Start with their highest-traffic pages, not their full keyword list. Export their top 50 ranking pages by estimated traffic, find which topics those pages cover, and identify the two or three clusters most relevant to your offering. Build those first.

Should I target keywords my competitors rank #1 for, or look for terms where they're weaker? Both, with different timelines. Start with keywords where they rank positions 5–20 — they've validated the topic but haven't locked it down. Pursue the #1 rankings as your domain authority grows.

Does this work for local businesses or only national/global sites? It works for local too, though your competitor set is smaller and the volumes are lower. The process is the same: find who ranks for your local keywords, see what else they rank for, and build pages you're missing.