What Is Bot Filtering on HubSpot Emails? (And Should You Care?)

A client asked us this week: "I saw a notice on my email that it's not eligible for bot filtering. What is that, and is it important?"

Great question. And one that a lot of HubSpot users have seen and ignored because the explanation in the platform doesn't make it any clearer really. So here it is.

What Bot Filtering Actually Is

Bot filtering is HubSpot's way of throwing out fake opens and clicks.

Here's what's happening behind the scenes. A lot of companies (especially in healthcare, finance, and any industry with strict IT security) run email scanning software. Mimecast, Barracuda, Proofpoint... these tools scan every inbound email before it hits the recipient's inbox. They open the email. They click every link. They check for threats.

That scanning looks exactly like a person opening your email and clicking your links. But it's not a person. It's a robot doing a security check.

Apple Mail does something similar with its privacy protection features. It pre-loads email content in the background so senders can't track whether someone actually opened the message.

Without bot filtering, all of that activity gets counted as real engagement. Your open rates look inflated. Your click rates look inflated. And your data starts lying to you.

Bot filtering catches those fake interactions using IP detection and behavioral patterns (like how fast the clicks happen... no human clicks six links in 0.3 seconds) and strips them out of your reporting.

Where It Lives

Bot filtering is on by default for marketing emails. The toggle is in Settings → Tracking & Analytics → Tracking Code. If you haven't touched it, it's probably already on.

You can check whether it was active for any specific send by opening the sent email and looking to the right of the Performance and Recipients tabs.

Sales emails handle this differently. HubSpot says it won't generate open or click events for sales emails when the interaction is non-human, so there's no toggle to manage.

Why It Matters Beyond Vanity Metrics

Here's the part that catches people off guard. Bot filtering doesn't just affect your email dashboard. It affects contact properties.

When HubSpot flags a bot open, the "Marketing emails opened" counter on the contact record doesn't increment. Which means bot filtering is quietly touching:

Workflow enrollment (if you're enrolling contacts based on email engagement). Lead scoring (if opens or clicks contribute to the engagement score). Lifecycle stage progression (if MQL or SQL triggers are tied to email activity). List segmentation (any list built on "has opened" or "has clicked" criteria).

Turn bot filtering off and you get inflated numbers across all of those systems. You could end up with MQLs that were created by a security scanner. Leads flagged as "highly engaged" that have never actually read an email. Workflows firing for contacts whose IT department did the clicking, not them.

The Imperfect Part

Bot filtering helps. It's not perfect.

Regulated industries get hit the hardest. Finance and healthcare especially, because corporate email security is aggressive. Some portals still see a meaningful chunk of engagement that's machine-generated even with filtering on. HubSpot's algorithms catch a lot, but they don't catch everything.

This is actually one of the reasons we build lead scoring models with fit and engagement as two separate scores. Contact fit (job title, company size, industry) and company fit (revenue, location, target vertical) don't get clicked by Mimecast. If your entire lead scoring model runs on email engagement, bot activity is inflating scores for contacts who may have never actually read a thing you sent.

Engagement should be one input. Not the whole model.

What About Email Types That Aren't Eligible?

This is what prompted the original question. Our client was looking at an RSS email (an automated email that sends whenever new blog content is published) and saw a notice that it wasn't eligible for bot filtering.

That's a HubSpot limitation on the email type. RSS emails, along with a few other automated types, don't support bot filtering. There's nothing to change in the email itself to turn it on. It's just how HubSpot built it.

Is that a problem? Not really. Filtered or not, the data is still directionally correct. The bots hit every send about the same way, so if something in the email is working (a new banner, a different CTA, a content change), you'll see the trend. Compare RSS sends to other RSS sends and you'll get a clean read. Just don't stack those numbers against your regular marketing emails, since those are filtered and these aren't. Apples to apples.

If you want a tighter look at whether a specific link or banner in an unfiltered email is driving real behavior, skip the click data entirely and look at actual page visits. That's a cleaner signal because bots don't visit your website... they just click links inside the email.

What You Should Do

Make sure bot filtering is on. It should be by default, but check. Settings → Tracking & Analytics → Tracking Code.

Don't build critical automations on email engagement alone. If your MQL trigger is "opened three emails," that MQL might be a Mimecast server in a data center somewhere. Pair engagement criteria with fit criteria so your scoring model has a foundation that bots can't inflate.

Compare like to like. If you're looking at an email type that isn't eligible for filtering (RSS, some automated types), compare it against other sends of the same type. The bot activity will be consistent across those sends, so the trends are still meaningful.

Use page visits as a backup signal. If you want to know whether someone actually engaged with your content (not just whether their email security software clicked the link), look at whether they visited the page. That's a human behavior that bots don't replicate.

Don't panic about it. Bot filtering is one of those things that's easy to overthink. For most portals, turning it on and building smart scoring models is enough. You don't need to audit every open and click. Just know that the numbers aren't perfectly clean, factor that into how much weight you put on email engagement, and move on.

If you want help auditing your email engagement data, building a lead scoring model that accounts for bot activity, or just figuring out whether your numbers are telling you the truth, that's what we do.