Building behaviour-based email campaigns: Interpolly

by Portfolio, Email copy

The Company

Interpolly turns YouTube videos into interactive language learning experiences. I was originally introduced to Interpolly when founder Marcell reached out to me to write landing page copy for their new site. About a year later I came back to Interpolly, this time as co-founder and leading our marketing initiatives. We eventually wound everything down as we decided that the Indie hacker life just wasn’t for us, but I’m very proud of the amazing work we accomplished together.

The problem

When I first came on as co-founder I conducted an audit of our entire onboarding process and there was a noticeable absence of any email marketing to support it. This meant that it was easier for users to sign-up, start using Interpolly, get distracted by a funny cat video on Instagram, and never return.

I wanted to create a stand-out onboarding email campaign that did five things:

  • Got them excited about using the product
  • Celebrated important milestones
  • Nudged them to use the product’s full features
  • Re-engaged users who were in danger of churning
  • Kept us top of mind through regular, helpful newsletters

What I did

First of all we chatted about the steps a user had to take before they experienced value from our product. We then turned those actions into events we could track in-app. These were things like, “viewed video”, “collected first word”, “taken first quiz” etc. Through some genius, dev magic Marcell then integrated our app analytics tool with our email marketing software, MailerLite, using *checks notes* APIs and webhooks.

I then set-up tags in MailerLite for these events and built automations around them. For example, when someone watched their first video in-app a little robot went and told MailerLite to send out a specific email celebrating that milestone and encouraging them to take the next step. I also set up a re-engagement email trigger when a user hadn’t logged in for two weeks (I even offered 20 minute calls to help them build their language learning routine). Finally, I made sending our weekly newsletter a top priority.

I am very passionate about newsletters and I’ve seen too many SaaS companies turn theirs into a link-dump of blogs they’ve published or only emailing their list to push promos or webinars.

Not cool.

I really wanted our newsletter to be a resource that language learners would enjoy even if they never converted into a user or a customer. I sent out a weekly email with language learning advice and even got a top French language influencer, Alex Barron of French in Plain Sight, to guest on one issue and share it with his huge audience.

Our average open rates were 44% and I don’t think we ever sent out a newsletter without getting replies. I credit this to the newsletter’s first-person style storytelling: people want to read content they know was written by a real person with real experiences. You can still be a “we” as a company, but your newsletter is sent out by someone on you team, let them have a voice.

Read the copy

Onboarding Email Sample

My experience of writing funnel copy for course creators taught me the importance of hyping up subscribers for taking action and this became key to our brand voice.


We wanted our newsletters to feel like they weren’t just from some faceless company which is why I wrote them in first-person and with my own stories. I also segmented our newsletter by which language the user was learning to make them more personal.

Re-activation email

This email was triggered when a user was inactive for two weeks and yep, I really did set up calls with users to help with their language goals.

Two women posing for a photo at a desk. Tactical Marketing with 4Zero Marketing

Hi I’m Kerry

I’m a copywriter and content marketer who helps brands like yours own their messaging, soar in search engines, and convert more leads into customers.


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