01
Audit
I review your onboarding, paywall, analytics and past tests to find where users drop off and what to test first.
Your paywall is leaking revenue
We find what’s stopping your users from paying and design the experiments that fix it.
Why aren’t your users paying?
1
You forgot about the onboarding
You’ve focused on the paywall, but purchase intent starts earlier. If users don’t understand the value, they won’t start a trial.
2
You’re not testing the placement
Even a high-converting paywall can underperform when it appears at the wrong moment in the user journey.
3
You’re not learning from the experiments
A/B testing shouldn’t just produce winners and losers. It should show you why, and what to test next.
4
You are leaving potential revenue behind
Users who do not subscribe immediately may still be interested. The right timing and follow-up can bring them back.
The method to improve conversion
02
Design the test
I turn the problem into a clear A/B test, from the hypothesis to the Figma screens and specs your developer needs.
03
Deliver
I give you everything needed to run the test: final designs, developer specs and a setup guide.
I also define the key metrics to track, from conversion and user behaviour to guardrails.
04
Analyse and iterate
I make sense of the data, explain what we learned, and decide what to do next.
Every experiment gives us a better understanding of your users, so the next test is based on evidence, not assumptions.
From digital strategy to paywall optimization
Sofia Mateo · Product Designer & Growth Strategist
After five years in the audit world, I moved into digital business strategy and growth, a path that led me to mobile apps. Along the way I’ve mentored 150+ entrepreneurs, designed 100+ experiments, and analysed hundreds of onboarding flows, paywalls and conversion funnels.
Today I work as a growth designer for consumer apps, helping product teams decide what to build next and find where their revenue is leaking.
Choose how you want to test
Single Experiment
$900per experiment
For one high-impact idea you want validated.
- Revenue audit
- 1 high-converting experiment
- Hypothesis definition
- Primary, secondary and guardrail metrics
- Figma designs + developer-ready specs
- Result analysis and learnings
WarrantyIf it doesn’t win on the agreed metrics, I run the next experiment for free.
Run an experimentGrowth Plan
Most popular$3,500per month
For testing every month, with me alongside you.
- Revenue audit
- High-converting experiments, run continuously
- Hypothesis definition
- Primary, secondary and guardrail metrics
- Figma designs + developer-ready specs
- Result analysis and learnings
- The next experiment, informed by the last
- Monthly strategy call + async support
Always onOne experiment is always running, one is ready to go.
Start the loopPayments secured by Stripe
From the founders
What changed after we started testing, in their own words.
“When Sofia joined us, only about 10% of our users were converting to paid. The root issue was something we hadn’t seen ourselves: we were asking users to subscribe before they’d experienced any real value. She redesigned onboarding around a personalised questionnaire, introduced an aha moment before the paywall, then restructured the paywall itself. She didn’t just redesign screens. She changed how we think about when and why users pay.”
Travel DiariesFounder“From day one she asked the right questions, challenged assumptions when needed, and took ownership of the project. After implementing her proposal, our A/B test showed a 17% increase in initial conversion rate, which translated to a huge uplift in our MRR. I really recommend her.”
Blackjack ApprenticeshipFounderGot questions? I’ve got answers
Who do you work with?
I work mainly with subscription apps that already have users and revenue.
For the monthly Growth Plan, I generally look for apps with at least 10,000 downloads and around $15,000 a month in revenue. You need enough users for experiments to produce useful results.
If your app is smaller, start with a Single Experiment.
My app is smaller than that. Can I still work with you?
Yes. We can run one experiment, wait for the data, and decide what to do next.
There is no monthly commitment. You pay for the experiment, get the result, and decide whether you want to continue.
I’ll also tell you when your app has enough users to make regular A/B testing worthwhile.
What tools do you use?
Whatever you’re already using. For example:
Paywalls: RevenueCat, Superwall, Adapty
Analytics: Mixpanel, PostHog, Amplitude
I don’t need you to change your tech stack to work with me.
Do you replace my designer or growth person?
No. Your designer keeps working on the product. I focus on the parts of the app that directly affect conversion.
I look at the data, decide what is worth testing, design the change, and give your developer everything they need to build it.
Your team keeps ownership of the product. I add the conversion work on top.
Should I test onboarding or the paywall first?
Usually, we’ll start with the paywall because it has the most direct impact on revenue.
But I don’t follow a fixed order. If we find a clear, high-impact opportunity somewhere else in the funnel, we may start there instead.
The important thing is to fix the biggest problem first. There’s little point in bringing more users to your paywall if the paywall isn’t converting them.
Do you implement the experiment, or does my developer?
Your developer builds it. I design and spec it. You get:
- The Figma design
- What needs to change
- The hypothesis we’re testing
- The main success metric
- Any important things we need to keep consistent
Your developer should be able to build the test without needing a meeting with me to explain every detail.
I don’t write Swift or React Native. That’s deliberate. It keeps the work focused and the turnaround fast.
How long until I see results?
It depends on how many users your app gets.
I’ll review your data before we start and tell you roughly how long the test needs to run. The more traffic you have, the faster you’ll get a reliable answer.
You won’t have to guess when the test has enough data. I’ll tell you when we have enough to make a decision.
What if an experiment doesn’t win?
That’s okay. A test that doesn’t improve the agreed metric still tells us something about your users.
For a Single Experiment, if the test doesn’t win, I’ll run the next experiment for free.
For the Growth Plan, we use the result to decide what to test next. That’s the point of running experiments continuously: each test gives us information that makes the next one better.
Can I cancel anytime?
Yes. The Growth Plan is month to month with no long-term contract. Just give me 15 days’ notice before your next billing cycle.
That said, testing works better when we have time to learn from several experiments. Each test gives us information that helps us choose the next one.