Do not launch your custom Stripe integration without this checklist.

The reason custom Stripe integrations leak money is rarely the obvious one. The Stripe SDK is good. The Stripe documentation is good. The mistakes are upstream of the API. A team treats Stripe webhooks as exactly-once delivery instead of at-least-once, and a single replay grants a customer two months of free access. A team forgets to set a 3D Secure fallback on a non-US payment method and the entire EU customer base hits a silent decline. A team writes the subscription state machine without modeling past_due-to-canceled transitions correctly and ends up with hundreds of customers stuck in zombie subscription states. None of those bugs are caught by Stripe's own test mode. They surface in production with revenue impact.

This checklist is the QA artifact our team runs on every custom Stripe integration engagement. It is also what we use when we do an inbound review of a Stripe integration a client built in-house. The pre-launch sections catch the bugs that hit you in Week 1. The post-launch monitoring sections catch the ones that hit you in Month 6.

The checklist is built for three audiences. First, engineering leaders and CTOs at SaaS or marketplace companies shipping a custom Stripe integration for the first time — replacing Stripe Checkout or Payment Links with a custom Stripe Elements flow, or moving from a legacy payment processor onto Stripe. Second, technical founders building a billing system into a post-MVP SaaS product who need a defensible pre-launch QA artifact for an upcoming enterprise sale. Third, engineering teams running an existing Stripe integration that has started producing customer support fires they cannot explain — failed webhook retries, dunning recovery numbers that look wrong, or reconciliation reports that take a half-day per month to close.

If you are using Stripe Checkout or Payment Links and have no plans to customize, the checklist is overkill — Stripe handles most of these concerns for you. If you are building marketplace payouts on Stripe Connect, several additional categories apply that are outside the scope of this checklist (KYC flows, payout schedules, capability lifecycle, dispute pass-through). We can cover those in a scoping call.

You will learn the idempotency-key pattern that survives Stripe's at-least-once webhook delivery semantics — and why the version that works in your test environment will fail under real load. You will learn the four hidden edge cases in the subscription state machine and the database schema that handles all of them. You will learn how to configure Stripe Smart Retries for the highest dunning recovery rate at your customer profile, the in-app reactivation prompt that adds 5-12 percentage points of recovery on top of the email cadence, and the metrics that turn dunning into a board-level number.

You will learn how to handle SCA-required payments correctly for EU and UK customers — the single most common source of silent decline rate inflation for US-built SaaS. You will learn the multi-currency rounding rules that Stripe applies and where they break your accounting reconciliation. You will learn the canonical refund flow that satisfies both customer-success expectations and finance audit requirements.

On the monitoring side, you will learn the four production dashboards you actually need — webhook delivery, subscription state distribution, dunning recovery, dispute and refund rate — and the threshold alerts that page your on-call engineer before customers tweet at support. Section 1 of this checklist is also a prerequisite for the payments pillar in the MVP to Production Playbook.

The checklist is the internal QA artifact we ship to every custom Stripe integration client on day one. It is also the framework our payments, invoicing, and licensing service runs against when we audit an existing integration. For broader billing systems — subscription billing, license servers, or full revenue stack — the checklist is one of the four artifacts that governs the build.

To estimate the cost of a custom Stripe build at your scope, run the Stripe integration cost calculator. To see how a Stripe integration sits inside a larger SaaS architecture, read the MVP to Production Playbook. For engagement pricing, see the pricing page or browse sample builds and read about QUANT LAB.