How to Add Payments to Your Mobile App: Stripe, Apple Pay, Google Pay — and What PCI Compliance Really Requires

Adding payments to your mobile app looks like one line on the feature list. In practice it's three separate decisions — which payment rails Apple and Google will even allow you to use, which payment gateway processes the money, and how much of PCI DSS compliance lands on your business — and getting any of them wrong is expensive in the worst ways: rejected app submissions, surprise commissions, or a security assessment you never budgeted for. Here's how payment gateway integration in a mobile app actually works, in plain English, from a team that builds this for a living.

First rule: Apple and Google decide before you do

The most misunderstood part of mobile payments has nothing to do with technology. Apple's App Store rules draw a hard line: if you're selling digital goods or features consumed inside the app — subscriptions to content, premium features, credits, courses delivered in-app — you must use Apple's in-app purchase system, which takes a commission of 30%, or 15% for developers under US$1 million in annual revenue through the App Store Small Business Program. Google Play's billing policy works the same way at similar rates. But if you're selling physical goods or real-world services — food, products, bookings, rides, appointments — Apple's guideline 3.1.3(e) requires the opposite: you must use purchase methods other than in-app purchase, such as a payment gateway or Apple Pay. Classify your product wrong and the app gets rejected in review; classify it right and you may keep an extra 15–30% of every sale. This is a business-model decision, and it belongs at the start of the project, not the end.

Payment gateway integration: how the money actually moves

For everything outside in-app purchase, you integrate a payment gateway — Stripe, Square, Moneris, and their peers. Done properly, the integration follows one golden pattern: the customer's card details go from the phone directly to the gateway, which returns a token your app and server use in its place. The card number itself never touches your server, never sits in your database, and never appears in your logs. Modern gateway SDKs make this the path of least resistance — Stripe's mobile SDKs ship prebuilt, tokenizing payment screens for exactly this reason. Your server's job is small but non-negotiable: create the payment on the gateway, confirm the result server-side, and never trust an "it worked" message from the app alone — anything running on a customer's phone can be tampered with.

Apple Pay and Google Pay: wallets, not processors

A common confusion: Apple Pay and Google Pay are not payment processors and don't replace your gateway — they sit on top of it. The wallet hands your gateway an encrypted, tokenized card; the gateway processes it like any other payment, and for physical goods and services neither Apple nor Google charges an additional fee on top of your normal processing costs. What the wallets buy you is conversion: checkout collapses from a form full of card fields to a thumbprint or a glance. On mobile — where typing a card number one-handed on the subway is where sales go to die — supporting both wallets is close to mandatory, and every serious gateway supports them with modest extra integration work.

The safest place to store a customer's card number is nowhere.

What PCI DSS actually requires from your business

PCI DSS — the Payment Card Industry Data Security Standard, maintained by the PCI Security Standards Council — applies to every business that stores, processes, or transmits cardholder data. The compliance burden, though, depends dramatically on how the card data flows:

• If card data passes through or is stored on your servers, you're exposed to the full standard — hundreds of security controls, dedicated tooling, and potentially external assessments. For a small business, that's a cost and a liability you should almost never accept.
• If you use a gateway's SDKs or hosted payment fields so card data goes straight from the customer's device to the processor, your obligations shrink to the simplest self-assessment tier — the outcome every sanely built app should target.
• Either way, compliance isn't zero: expect an annual self-assessment attestation, TLS on every connection, access controls on your systems, and verification that your processor is itself a certified PCI Level 1 service provider (the major gateways publish this).
• You can safely store what the gateway returns — tokens, card brand, last four digits, expiry — which is everything a normal app needs for "your Visa ending in 4242" receipts and saved payment methods.

Building it right the first time

Payment code is the one part of an app where "we'll clean it up later" is genuinely dangerous — later arrives as a chargeback dispute, a failed assessment, or a rejected release. When we build payment features inside a custom software development engagement, the payment architecture — in-app purchase vs gateway classification, tokenization flow, server-side confirmation, webhook handling for the payment events that happen while the app is closed — is designed and reviewed before the first screen is styled. The same foundations apply beyond apps: our ecommerce development team wires the identical gateway stack into Shopify, WooCommerce, and custom storefronts, and our guide to building a payment system for your business covers the subscriptions, billing, and fee mechanics that come next. If your app needs to take money — or is being rejected because of how it takes money — call us or use the contact form on our homepage.