A Guide To Stripe Integration in Spring Boot Application

As digital transactions rise, the ability to seamlessly integrate payment gateways has become a critical skill for developers. Whether for marketplaces or SaaS products, a payments processor is crucial to collect and process user payments.

This article explains how to integrate Stripe within a Spring Boot environment, how to set up subscriptions, offer free trials, and build self-service pages for your customers to download their payment invoices.

What Is Stripe?

Stripe is a globally renowned payment processing platform available in 46 countries. It is a great choice if you want to build a payment integration in your web app owing to its large reach, reputed name, and detailed documentation.

Understanding Common Stripe Concepts

It’s helpful to understand some common concepts that Stripe uses to coordinate and carry out payment operations between multiple parties. Stripe offers two approaches for implementing payment integration in your app.

You can either embed Stripe’s forms within your app for an in-app customer experience (Payment Intent) or redirect customers to a Stripe-hosted payment page, where Stripe manages the process and lets your app know when a payment is successful or failed (Payment Link).

Payment Intent

When handling payments, it’s important to gather customer and product details upfront before prompting them for card information and payment. These details encompass the description, total amount, mode of payment, and more.

Stripe requires you to collect these details within your app and generate a PaymentIntent object on their backend. This approach enables Stripe to formulate a payment request for that intent. After the payment concludes, you can consistently retrieve payment details, including its purpose, through the PaymentIntent object.

Payment Links

To avoid the complexities of integrating Stripe directly into your codebase, consider utilizing Stripe Checkouts for a hosted payment solution. Like creating a PaymentIntent, you’ll create a CheckoutSession with payment and customer details. Instead of initiating an in-app PaymentIntent, the CheckoutSession generates a payment link where you redirect your customers. This is what a hosted payment page looks like:

The Stripe-hosted checkout page showing invoice details on the left and the payment details collection form on the right.
The Stripe-hosted checkout page.

After payment, Stripe redirects back to your app, enabling post-payment tasks such as confirmations and delivery requests. For reliability, configure a backend webhook to update Stripe, ensuring payment data retention even if customers accidentally close the page after payment.

While effective, this method lacks flexibility in customization and design. It can also be tricky to set up correctly for mobile apps, where a native integration would look far more seamless.

API Keys

When working with the Stripe API, you will need access to API keys for your client and server apps to interact with the Stripe backend. You can access your Stripe API keys on your Stripe developer dashboard. Here’s what it would look like:

The Stripe dashboard's developer section showing the API keys tab.
The Stripe dashboard showing API keys

How Do Payments in Stripe Work?

To understand how payments in Stripe work, you need to understand all the stakeholders involved. Four stakeholders are involved in each payment transaction:

  1. Customer: The person who intends to pay for a service/product.
  2. Merchant: You, the business owner, are responsible for receiving payments and selling services/products.
  3. Acquirer: A bank that processes payments on behalf of you (the merchant) and routes your payment request to your customer’s banks. Acquirers may partner with a third party to help process payments.
  4. Issuing bank: The bank that extends credit and issues cards and other payment methods to consumers.

Here’s a typical payment flow between these stakeholders at a very high level.

A basic workflow showing how online payments are handled by the customer, merchant, acquirer, and the issuing bank
How online payments work

The customer lets the merchant know they’re willing to pay. The merchant then forwards the payment-related details to their acquiring bank, which collects the payment from the customer’s issuing bank and lets the merchant know the payment was successful.

This is a very high-level overview of the payment process. As a merchant, you only need to worry about collecting the payment intent, passing it on to the payment processor, and handling the payment result. However, as discussed earlier, there are two ways you could go about it.

When creating a Stripe-managed checkout session where Stripe takes care of your payment details collection, here’s what the typical flow looks like:

The Stripe hosted checkout payment workflow showing how the payment is handled between the client, the server, the Stripe API, and the hosted Stripe Checkout page.
The Stripe hosted checkout payment workflow. (Source: Stripe Docs)

With custom payment flows, it’s really up to you. You can design the interaction between your client, server, customer, and the Stripe API based on your app’s needs. You can add address collection, invoice generation, cancellation, free trials, etc., to this workflow as you need.

Now that you understand how Stripe payments work, you are ready to start building it in your Java application.