Define the North Star metric for Connect serving SaaS companies

Problem Statement Description

Product context: Stripe is financial infrastructure for internet businesses; its products include payments, Checkout, Billing, Connect, Radar, Issuing, Terminal, and tax tools.

Stripe Connect enables SaaS platforms to embed payments and money movement for their own customers, such as vertical SaaS tools, marketplaces with SaaS workflows, or business software platforms that monetize through payments. In this interview, you are asked to define a North Star metric for Connect specifically for SaaS companies, not for Stripe as a whole or for all Connect segments.

Frame the problem around the SaaS platform’s workflow: onboarding businesses, enabling them to accept payments, managing compliance and risk, supporting recurring or usage-based revenue, and helping those businesses grow reliably. The metric should reflect durable value created for the SaaS platform, its end merchants, and Stripe, while avoiding short-term volume signals that could hide poor activation, fraud, churn, or low-quality growth.

Your task is to explain what the North Star should capture, how it would be measured, and why it would guide product decisions across onboarding, APIs, billing/payment flows, risk, compliance, and merchant success.

The metric definition should consider:

- The exact user/customer whose success is being measured: SaaS platform, connected merchant, or both.

- The numerator and denominator, including what counts and what is excluded.

- How the metric would be instrumented across Connect accounts, payment flows, onboarding states, and recurring SaaS usage.

- Relevant cohorts, such as new vs. mature platforms, SMB vs. enterprise SaaS, geography, business model, or integration type.

- Guardrail metrics for reliability, fraud, disputes, compliance failures, churn, support burden, and developer experience.

- How the metric distinguishes healthy merchant growth from raw payment volume or one-time spikes.

- How it would help product teams prioritize roadmap decisions and evaluate launches.

- Trade-offs versus alternative metrics that may be easier to measure but less representative of long-term value.

The goal is to define a clear, decision-useful North Star metric for Stripe Connect’s SaaS segment, along with the supporting measurement logic and guardrails needed to make it actionable for product strategy and execution.