Requirements for adding custom payments app into checkout

Topic summary

A developer is seeking clarification on the requirements for integrating a custom payment app into Shopify. The specific use case is narrow: the payment app would only be used for a single customer in a single market.

The main question is whether the standard Shopify payment app approval process applies, or if there’s a lighter/simplified process available for custom payment apps with such limited scope.

The discussion references Shopify’s payment partner application review documentation but remains unanswered regarding alternative pathways for single-customer implementations.

Summarized with AI on November 24. AI used: claude-sonnet-4-5-20250929.

Hi, I would like to understand what are the requirements for adding custom payment app into Shopify. Aim would be to use this payment app for a single customer on a single market. Would the process be the same as described in https://shopify.dev/apps/payments#payments-partner-application-review or is there a lighter process for custom payments apps that would be used in one particular shop/market.