Stripe · Metrics · Mid · 45 to 60 minutes

Should Stripe show BNPL at checkout?

Stripe provides payments infrastructure and checkout tools for internet businesses. Answer this product management case and get it graded line by line against a weighted rubric.

Metric design
Experimentation
Trade-off analysis
Product judgment
Communication

The situation

You are the PM for Stripe's checkout optimization and payment methods experience. A merchant, Mixtiles, asks whether adding a buy now, pay later option at checkout will help or hurt its business. The concern is not simple adoption. BNPLs are usually more expensive than card payments, so the merchant worries that an extra option could add checkout friction, reduce completion, or shift existing card customers into a higher cost method without creating much new demand. Stripe leadership sees this as a broader product question for many B2C businesses using Stripe, not a one-off account request. If Stripe is going to recommend BNPLs, surface them in product, or build self-serve guidance, it needs evidence that captures the full business impact of showing BNPL at checkout. You have access to Stripe's network-level checkout and payment data across eligible merchants, but you cannot assume every merchant can run a long custom study on its own. Your task is to define how Stripe should evaluate whether showing BNPL at checkout is worth it, and how the team should decide what to recommend.

What to produce

Write a 1 to 2 page experiment and metrics memo.

Your answer must

State the product decision Stripe is trying to make, and name the primary user or customer affected by that decision.
Define a metric framework with one primary outcome metric and supporting metrics that capture checkout friction, payment method mix, and business impact.
Propose an experiment design that includes treatment and control, unit of randomization, target population, and at least two useful segments to analyze separately.
Explain how you would detect cannibalization versus net-new sales, and how those findings would change your recommendation.
End with a clear decision framework for when Stripe should encourage merchants to show BNPL, when it should ask them to test, and when it should be cautious.

Constraints

Focus only on checkout sessions where a BNPL method is eligible to be shown and at least one other payment method is available.
The approach must produce guidance that can work across many B2C Stripe merchants, not just a custom answer for one merchant.
Your recommendation must consider total economics, including the higher cost of BNPL relative to cards, not just BNPL adoption or conversion alone.
Use only signals Stripe can reasonably observe in checkout and payment outcomes, such as conversion, order value, refunds, disputes, and payment method selection.

Format

Use sections titled Decision, Metrics, Experiment, Risks and trade-offs, and Recommendation. A simple metric tree or table is welcome.

How Stripe actually played it

A Mixtiles product lead asked whether buy now, pay later would add checkout friction or cannibalize card volume. Stripe ran experiments across its network and reports that sessions where a BNPL option was eligible saw up to a 14 percent revenue increase from higher conversion and order value. A tidy example of answering a product question with an experiment.

Frame the experiment around the fear (friction, cannibalization).
Measure revenue, not just conversion.
Network-level data can settle questions a single store cannot.

Built from Testing the impact of buy now, pay later across 150,000+ checkout sessions by Stripe.