Pick Similarweb if your main question is “How much traffic do competitors get from email?” Pick Semrush if your main question is “How does email fit with SEO, PPC, and content?” That is the simplest split. Both tools help, but neither shows a rival’s private open rates or full email list.
TLDR: Similarweb is cleaner for spotting competitor email traffic patterns. Semrush is stronger for linking email pushes to search ads, keywords, landing pages, and content. For example, if Competitor A gets 7.8% of traffic from email and Competitor B gets only 2.1%, Similarweb helps you see who treats email as a major channel. Semrush then helps you check if that same brand also boosted paid search by 18% that week.
What “competitive email analysis” really means
Let’s clear this up early. You cannot open a tool and see your competitor’s exact email open rate. You cannot see their full subscriber list. You cannot see who clicked every button. That would be creepy. Also illegal in many cases.
What you can see is useful enough.
- How much website traffic may come from email.
- Which competitors depend on email more than others.
- Which landing pages get pushed.
- When campaigns seem to spike.
- How email works with ads, search, and content.
Think of it like watching footprints in mud. You do not see the whole person. But you can tell where they walked, how often, and where they probably went next.
Similarweb: best for traffic clues
Similarweb is very good at channel-level competitor analysis. It shows estimated traffic sources. That includes direct, organic search, paid search, referrals, social, display, and email.
For email marketing analysis, this is gold. You can compare brands side by side. You can see if email is tiny, healthy, or weirdly huge.
Say you compare three ecommerce brands:
- Brand A: 8.4% of traffic from email.
- Brand B: 3.2% from email.
- Brand C: 0.9% from email.
Brand A probably has a stronger newsletter engine. Or frequent promos. Or a better customer base. Brand C may be weak at retention. Or it may use SMS, apps, or marketplaces instead.
Similarweb also helps you study timing. If email traffic jumps in late November, the brand may be running Black Friday campaigns. If it spikes every Tuesday, they may have a weekly send rhythm.
What Similarweb does well:
- Shows estimated email traffic share.
- Makes competitor comparison simple.
- Spots traffic spikes fast.
- Shows which channels support each other.
- Works well for market sizing.
Where it gets annoying: some smaller sites have thin data. You may click into a smaller competitor and get vague estimates. Honestly, it feels like checking a fridge and finding only mustard. Technically useful. Not dinner.
Semrush: best for the bigger marketing picture
Semrush is not only about email. That is the point. It is strong because it connects competitor activity across SEO, paid search, content, backlinks, display ads, and traffic trends.
If Similarweb tells you email traffic went up, Semrush helps you ask why.
Maybe the competitor launched a new landing page. Maybe they ranked for new sale keywords. Maybe they ran paid ads to the same product page. Maybe a blog post started pulling traffic, then email pushed readers to a discount page.
This is where Semrush feels more like a detective board. Strings. Pins. Coffee. Mild panic.
What Semrush does well:
- Finds competitor keywords.
- Shows paid search ads and landing pages.
- Tracks content performance.
- Monitors traffic sources with its traffic tools.
- Helps connect email activity to wider campaigns.
The catch is that email data is not always the star of the show. You may need to jump between several reports. It drives me crazy that a simple question can take six clicks instead of two. Still, the added context is often worth it.
Side by side: Similarweb vs Semrush
| Need | Better choice | Why |
|---|---|---|
| Compare email traffic share | Similarweb | It is faster for channel mix checks. |
| Study landing pages | Semrush | It links pages to keywords, ads, and rankings. |
| Spot campaign spikes | Similarweb | Traffic trend charts are easy to scan. |
| Understand SEO and PPC overlap | Semrush | Its search data is deeper. |
| Build a boardroom snapshot | Similarweb | Clean visuals and quick market comparisons help. |
| Build a campaign plan | Semrush | It gives more action points for content and ads. |
A simple use case
Imagine you run a skincare store. Your competitor just had a sales jump. You want to know if email helped.
First, open Similarweb. Check traffic sources for the last three months. You see email traffic rose from 2.5% to 6.9% in April. That is a big lift. Not proof, but a strong clue.
Next, check the top pages getting traffic. You notice a “Spring Glow Kit” page appeared during the same period. Nice. Now the plot thickens.
Then open Semrush. Search the competitor domain. Look at new keywords, paid ads, and landing pages. You find that they started bidding on “vitamin c skincare set” and “spring skincare bundle.” Paid search traffic also rose by 22%.
Now you have a story. They likely ran a spring offer across email and paid search. Their email list may have warmed up the audience. Their ads may have caught shoppers who missed the email.
Your move is clear. Build your own bundle. Write three email angles. Test one discount. Send traffic to one clean landing page. Track revenue per recipient, not just opens.
What these tools cannot tell you
This part matters. Do not overtrust the numbers. Both platforms use estimates. They are not your competitor’s CRM.
You usually will not get:
- Exact open rates.
- Exact click rates.
- Subscriber count.
- Email revenue.
- Subject line test results.
- Personalization rules.
So treat the data as a signal. Not a courtroom confession.
Want the missing creative details? Subscribe to competitor emails yourself. Use a clean inbox. Tag each email by offer, product, subject line, send day, and call to action. This old-school method still works. Boring? Yes. Useful? Very.
How to use both together
The best setup is simple.
- Start with Similarweb. Find who gets meaningful traffic from email.
- Mark the spikes. Note dates with sudden jumps.
- Check landing pages. See where users likely went.
- Move to Semrush. Check keywords, ads, and content around those dates.
- Subscribe manually. Capture the actual emails if possible.
- Build your test. Copy the strategy, not the wording.
This gives you a full view. Similarweb says, “Email traffic rose.” Semrush says, “Here is what else supported it.” Your inbox research says, “Here is the message they sent.” Together, that is strong competitive analysis.
Which one should you buy?
If you can only choose one, choose based on your job.
Choose Similarweb if you are a founder, growth lead, investor, or marketing manager who needs fast competitor channel insight. It is better for quick checks. It is also easier to explain to a non-technical team.
Choose Semrush if you run SEO, PPC, content, or full campaign planning. It gives you more ways to act after spotting a trend. It is better for building the next move.
For pure email traffic comparison, Similarweb wins. For connecting email to the rest of competitor marketing, Semrush wins. If your budget allows both, use both. If not, pick the one that answers your most painful question first.
Final pick: use Similarweb to spot the email signal. Use Semrush to explain the campaign behind it. Then use your own testing to beat it.