Estimate the annual addressable market for Checkout among platform businesses

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 wants to understand the annual addressable market for Checkout among platform businesses: companies that enable many third-party sellers, creators, service providers, or merchants to accept payments through their software ecosystem. Examples may include marketplaces, SaaS platforms with embedded payments, booking platforms, creator platforms, vertical SaaS tools, and commerce enablement platforms.

In this guesstimate, your task is to size the opportunity for Stripe Checkout specifically, not Stripe’s entire payments, billing, or financial infrastructure business. Checkout should be treated as a hosted or prebuilt payment experience that helps platforms improve conversion, support payment methods, manage compliance complexity, and scale globally for their connected businesses.

You should define the market boundary clearly, choose a practical unit of analysis, and estimate annual addressable revenue or payment volume in a way that is useful for a Stripe product or strategy team. You may make reasonable assumptions, but you should state them explicitly and show how changes in key assumptions would affect the estimate.

The experience should consider:

- The definition of “platform businesses” and which subsegments are included or excluded

- Whether the market is sized by gross payment volume, Stripe revenue, Checkout-specific revenue, or another unit

- The number of eligible platforms and/or the number of merchants or sellers they support

- Adoption assumptions for hosted checkout among platforms versus custom-built payment flows

- Average transaction volume, transaction frequency, take rates, and geographic mix

- Differences between small, mid-market, enterprise, and global platform businesses

- Competitive and substitution factors, including in-house checkout, Adyen, PayPal, Square, Razorpay, and Checkout.com

- Sensitivity checks for the highest-impact assumptions and sanity checks against payments industry scale

Your goal is to produce a structured, defensible estimate of the annual addressable market for Stripe Checkout among platform businesses, while making clear what is in scope, what assumptions drive the result, and how confident a product team should be in the final range.