We treat email like infrastructure.

Notification Harbor started in 2024 in a windowless office in Brooklyn. Two of us (Maya, the technical lead, ex-Stripe infra; Theo, the product lead, ex-Linear) had each, separately, written the same 800-line "wrap our transactional email provider with templating + segmentation + retries" Python module at four different companies. Both of us, the fourth time, asked the same question: why does this not exist as a product?

The honest answer is: it does, kind of. Mailchimp exists. Klaviyo exists. Resend exists. Customer.io exists. But they each pick one corner of the problem — newsletters, ecommerce flows, transactional, lifecycle — and ignore the rest. Product teams end up gluing three of them together with internal infra, and the gluing layer is where all the bugs live.

The bet

We bet that an AI-native foundation would let us collapse the four products into one without losing depth in any of them. The LLM handles the "what to write" problem (which is what Mailchimp's drag-and-drop tries to solve). A signal-driven personalization engine handles the "what each person should see" problem (which is what Klaviyo's flows try to solve). A send-time scheduler handles "when to send" (which Customer.io got right and most others didn't bother). And a clean transactional API layer handles the rest.

The result, after 14 months, is Notification Harbor. We shipped public beta in March 2025. We're profitable. We have 800 paying teams. We're hiring engineers in NYC and Lisbon.

What we don't do

We don't sell "marketing automation," and we don't talk about "the customer journey." We build the email backend product teams use to talk to their users. That's it. If you want a vendor with a four-quadrant Forrester chart, we are not it.

Who's funding this

We raised a $4.2M seed in late 2024 from a single fund (no SPVs, no party round). The fund cares about runway and revenue, not about quarterly storytelling. We have 32 months of runway at current burn. We expect to be cashflow-positive on operations in Q3 2026.

Where to find us

Office is in Brooklyn (DUMBO). Half the team is remote across NYC, Lisbon, Berlin, and Montréal. If you want to swing by, we do walk-in office hours every Thursday 2-4pm ET — email theo@notificationharbor.com.