Payment Gateway Integration in a Web or Mobile App
A Comprehensive Guide
ScienceSoft applies 33 years of experience in software integration and 15-year expertise in fintech to help businesses integrate payments in their web and mobile applications.
Payments Integration in a Web or Mobile App: Summary
Integration of payment functionality in a web or mobile application aims to help companies smoothly, quickly, and securely accept digital payments from customers.
Key project steps: Business needs analysis and requirements elicitation, integration conceptualization, project planning, tech stack selection, integration implementation and quality assurance, support and evolution of the integrated system.
Timelines: 2–5+ months, depending on the chosen approach to payments integration.
Cost: $20K–$100K to integrate a market-available payment gateway, $100K–$300K to build and integrate a custom payment gateway.
Team: a project manager, a business analyst, a solution architect, developers, a DevOps engineer, a QA engineer.
ScienceSoft provides all necessary talents to help our customers seamlessly integrate payment functionality in their web and mobile applications. We ensure prompt and high-quality integration with minimal disruption to internal business processes due to proven tech skills and multi-industry expertise of our team.
Apps That Will Benefit from Payments Integration
In web development since 1999 and in mobile development since 2005, ScienceSoft helps companies in 30+ industries design and build reliable web and mobile apps tailored to their business needs. Based on ScienceSoft’s experience, the following types of apps would benefit from the integrated payment functionality the most:
How to Integrate Payments in an Application
To enable payment functionality, your application should be integrated with an online payment gateway. Such software:
- Connects to a web and/or mobile application that hosts a checkout page to collect purchasing details, personal information, and payment data (e.g., credit card data) provided by customers.
- Encrypts sensitive data and transfers it securely to a payment processing system of an acquiring bank, an independent payment processing provider (e.g., PayPal, Stripe, Authorize.Net), or the company (in case of relying on in-house payment processing). The payment processing system verifies the customers’ personal and financial data and transmits transaction details to a payment processing network (e.g., a card network) that connects to the customer’s bank to finalize settlement.
- Integrates with an accounting system to instantly communicate data on the successful payments and receive triggers to charge the recurring payments.
A Sample Architecture of Online Payment Gateway Integration by ScienceSoft
There are two main approaches to integrating a payment gateway with your application, each with its benefits and limitations. Here at ScienceSoft, we are ready to help you choose the optimal approach to meet your payment handling needs.
1. Integrating a market-available payment gateway
With this approach, you rely on a prebuilt payment gateway offered by a third-party payment processing provider (e.g., an acquiring bank, PayPal, Stripe, Authorize.Net) to handle customer payments. Such solutions offer ready-to-use APIs to facilitate and speed up integration with arbitrary apps and provide plug-and-play integrations with popular ecommerce platforms, accounting software products, analytical tools, etc.
Depending on the chosen payment gateway’s type – self-hosted or hosted – checkout can take place in your app or on a payment provider’s website. The former option provides a more consistent payment experience for customers and offers flexibility in terms of solution customization and branding. The latter option is more cost-effective as it doesn’t require maintaining a payment data storage infrastructure and achieving compliance with data security standards, such as PCI DSS. For more information, check our detailed comparison of hosted vs. non-hosted payment gateways.
Main benefit: A fast and easy way to integrate payments in the app with no investments in custom design of integration solutions and components (APIs, payment buttons, redirect scripts, webhooks, etc.).
- The need to pay fees for the payment gateway provider’s services, including a one-time gateway setup fee, a monthly gateway fee, a merchant account setup fee, and a fee for each transaction processed.
- Costly and lengthy integration with your legacy apps.
- Customizing a prebuilt payment gateway to the company’s business-specific needs may be effort-consuming or impossible.
2. Building and integrating a custom payment gateway
With this approach, we develop an online payment gateway from scratch and build custom APIs to integrate the solution with your required business applications. Integration with an external payment processing system is enabled by the ready-made APIs that a payment processing provider (typically, an acquiring bank) provides.
- Minimized operational and security risks due to complete control over the checkout flow, transfer and storage of sensitive data.
- Tailored functionality (support for all required payment methods, including cryptocurrency payments, recurring payments, refund processing) and required scalability, speed, and security of payment data processing to fully meet your unique needs.
- Flexibility to evolve the payment gateway and add new features when needed.
- Seamless integration with legacy web and mobile applications and corporate systems.
- No fees for the payment gateway providers’ services.
- The need to invest in custom solution design.
- Responsibility for setting up and maintaining payment data storage infrastructure, as well as obtaining PCI DSS compliance, is fully on your side.
Note! As an alternative to custom payment gateway implementation, you may consider integrating your application with multiple prebuilt payment gateways. It could help overcome functional, non-functional, and geographical constraints of each particular ready-to-use solution. However, this option may appear economically unfeasible even for larger enterprises as it requires substantial investments in integration efforts and goes with large payment gateway license fees.
Business analysis and requirements elicitation
Duration: 1–3 weeks.
ScienceSoft starts any payments integration project with a thorough analysis of a client’s needs and expectations. We closely collaborate with project stakeholders to collect the answers to the following key questions:
- What payment methods should the payment gateway support? (a credit/debit card, an e-wallet, crypto, etc.)
- In which regions should payments be available? (globally or in specific countries)
- What volume of transactions should the solution be able to process? (daily, monthly, during peak periods, etc.)
- Are there any specific requirements for the customers’ checkout experience? (in-app payments only or redirect is possible)
After that ScienceSoft’s consultants analyze the company’s existing IT infrastructure and the applications to be integrated with an online payment gateway to understand their capabilities and constraints. Also, we define the data to be shared (customers’ personal information, credit card data, etc.), figure out how it should flow and whether it needs to be transformed into a different format.
One more important point to analyze is potential regulatory risks and compliance requirements. This helps ensure the online payment gateway will meet PCI DSS requirements for secure credit card payments processing, AML and KYC requirements to prevent payment fraud, other industry- and region-specific regulations.
Once the analysis is done, ScienceSoft’s consultants prepare a detailed list of requirements for the integration solution, which describes:
- All the capabilities that the payments integration in the mobile and/or web app should provide.
- The required data inputs, outputs, and attributes of the online payment gateway.
- Non-functional requirements for the integrated system (availability, integrity, scalability, maintainability, performance, security, etc.).
Conceptualization of payments integration in the app
Duration: 2–5 weeks.
Upon forming a high-level vision, ScienceSoft proceeds with the design of a payments integration solution. This step involves making several important technical decisions:
- Deciding on the preferred type of an online payment gateway to integrate:
- a market-available payment gateway:
- a hosted payment gateway.
- a self-hosted white-label payment gateway.
- a custom payment gateway.
- a market-available payment gateway:
- (In case of opting for third-party software) Choosing an optimal prebuilt payment gateway according to the client’s specific criteria and business priorities. We at ScienceSoft perform a detailed comparative analysis of possible solutions to recommend the one that offers the required features and ensures economic feasibility.
- Defining the appropriate payments integration pattern depending on the selected type of a payment gateway:
- Embedding payment buttons and redirect scripts into the checkout interface.
- Relying on ready-to-use integration APIs provided with market-available online payment gateways.
- Designing custom APIs to integrate custom online payment gateways or smoothly connect OOTB solutions with the existing customer-facing applications.
A payment gateway type and an integration pattern, as well as functional and non-functional requirements to the payments solution, provide a basis to design the integration architecture.
Additionally, ScienceSoft designs a custom payment gateway and creates a custom UI of a checkout page, if required.
Duration: 1–2 weeks.
During this stage, ScienceSoft introduces a detailed integration project plan, which defines:
- Project deliverables.
- Project duration and budget.
- Critical milestones, objectives, and KPIs for the project.
- Project-associated risks and the ways to mitigate them.
- Expected TCO and ROI of the integration solution.
Choosing an integration tech stack
Duration: 2–3 weeks.
ScienceSoft defines the techs and tools required to integrate a payment gateway with your web and/or mobile app, relevant back-office systems (e.g., accounting software), and an external payment processing system. We compare various integration techs and tools in the context of the documented business requirements and select the optimal ones.
Best practice: In our payments integration projects, ScienceSoft’s team relies on well-established platforms, frameworks, and ready-made components where possible to streamline integration implementation, ensure its high quality, and optimize the project cost.
Payments integration implementation and quality assurance
Duration: 2–8 weeks, depending on the chosen integration pattern (custom payment gateway development and integration may be significantly longer than integrating a market-available solution).
The implementation of payments integration with ScienceSoft usually covers:
- Developing and deploying a custom web and/or mobile payment gateway (if required).
- Depending on the chosen type of a payment gateway and an integration pattern:
- Developing and installing custom integration APIs.
- Setting up ready-to-use APIs.
- Building payment buttons, redirect scripts, webhooks, and other required components and incorporating them into the checkout interface.
- Establishing further integrations with the required solutions (a web and/or a mobile app, a payment processing system, accounting software).
- Implementing security tools (authorization controls for APIs, transaction validity confirmation mechanisms, DDoS protection algorithms, firewalls, IDSs / IPSs, DLP systems, etc.) to ensure protection of the integrated system and the sensitive data it processes and stores.
ScienceSoft’s team performs quality assurance of each component of the solution in parallel with coding to eliminate possible vulnerabilities and logic errors and guarantee proper functioning of all uni- or bidirectional queries between the connected applications.
Note: Before launching the payment features in your app, you need to establish a merchant account with a bank to receive customer payments. In case of relying on a prebuilt payment gateway, you also need to establish a merchant account with a payment processor (e.g., PayPal, Stripe, Authorize.Net) to manage the received funds.
Prior to payment gateway implementation in the real environment, you need to obtain PCI DSS compliance. This is critical in the case of building a custom payment gateway or setting up a self-hosted OOTB solution.
After-launch support and evolution of the integrated system (optional)
- Fixing payment gateway performance and scalability issues, if any.
- Adjusting the payments integration solution’s functionality to the changing business needs (e.g., adding new payment methods).
- Monitoring and maintaining payment gateway compliance with PCI DSS and other relevant data security standards and regulations.
Consulting on payments integration
- Help you conceptualize a payments integration solution.
- Define the optimal integration patterns for a payment gateway.
- Determine the integration architecture and tech stack.
- Advise on an integrated system’s security.
- Help comply with PCI DSS and other relevant standards.
- Deliver a detailed payments integration roadmap for your app.
Our team takes over:
- Payments integration solution conceptualization and feature mapping.
- Integration architecture design.
- Custom payment gateway development (if required).
- Payment gateway integration with required systems and apps.
- Quality assurance of the integration solution.
- Payments integration launch and support.
- Further evolution of the integration solution (optionally).
Why integrate payments in the application with ScienceSoft
- Since 1989 in application integration services.
- Since 2007 in financial software development.
- 19 years in cybersecurity to ensure world-class protection of payments integration solutions.
- Practical knowledge of 30+ industries, including ecommerce, BFSI, healthcare, telecoms, professional services.
- Well-established Lean, Agile, and DevOps practices.
- A quick project start (1–2 weeks) and frequent releases (every 2–3 weeks).
- A mature quality management system and customer data security backed up by ISO 9001 and ISO 27001 certifications.
- Listed among the Americas’ Fastest-Growing Companies 2022 by Financial Times.
- Plans the project scope (goals, timeline, budget).
- Manages the project team.
- Controls the integration progress.
- Communicates with the stakeholders and reports the progress to them.
- Elicits, prioritizes, and documents the requirements for the payments integration solution.
- Chooses an approach to payments integration (in collaboration with the solution architect).
- Defines a payments integration approach (in collaboration with the business analyst).
- Architects the integration solution.
- Designs frameworks and processes to support the implementation of an integration solution.
- Write custom integration code (APIs, redirect scripts, etc.).
- (in case of integrating a prebuilt payment gateway) Set up triggers and choose resulting actions for customer and payment data sharing.
- Develop the UI and the back end of a custom payment gateway (if required).
- Fix code issues on a QA engineer’s notices.
- Configures the infrastructure for the payments integration solution.
- Automates integration processes by introducing a CI/CD pipeline.
- Designs and implements a test strategy, a test plan, and test cases for the payments integration solution.
- Verifies the integration solution’s adherence to the quality standards defined in the project plan.
NB! ScienceSoft is ready to provide additional talents, for example, UX and UI designers to design a checkout page for your application.
- Payments integration is fully under your control.
- Risk of delays and compromised quality due to the lack of specific integration competencies on board.
Turn to ScienceSoft to get assistance on the integration process planning and integration design.
- Prompt access to the required tech skills and optimal utilization of in-house resources, which helps to balance integration project costs.
- All project management efforts are on your side.
Turn to ScienceSoft to quickly augment your in-house IT team with necessary talents.
- Quick project start and optimized integration budget. Plus, full responsibility for the integration process and resources lies on the vendor.
- Risks of relying on an inept vendor.
Turn to ScienceSoft to get an ISO-certified self-managed team of experienced professionals.
ScienceSoft’s Success Stories of Payments Integration
Payments Integration for a Messaging App with 900M+ Active Users
ScienceSoft integrated the Viber billing portal with PayPal and a card network (Visa, MasterCard, American Express) to provide seamless payment experience for the Viber app users. The payment module architecture we designed enables fast and easy integration of new payment methods. Also, ScienceSoft’s team implemented a range of security algorithms to protect the integrated system against XSS and CSRF attacks.
Payments Integration in a Government Customer Portal
ScienceSoft delivered an integration that connected a government customer portal with a banking module. Our team established integrations with international payment systems using CyberSource and Mastercard Payment Gateway Service to enable the customers to make convenient and secure payments.
A Telecom Provider’s Website Integration with PayPal
ScienceSoft integrated a website of an international WiFi service provider with PayPal to enable easy customer payments for subscriptions.
ScienceSoft’s Tech Stack for Payments Integration in the Application
ScienceSoft’s team usually relies on the following tools and technologies to streamline payments integration into web and mobile apps and ensure high quality of an integration solution.
Back-end programming languages
Our .NET developers can build sustainable and high-performing apps up to 2x faster due to outstanding .NET proficiency and high productivity.
ScienceSoft's Java developers build secure, resilient and efficient cloud-native and cloud-only software of any complexity and successfully modernize legacy software solutions.
ScienceSoft's Python developers and data scientists excel at building general-purpose Python apps, big data and IoT platforms, AI and ML-based apps, and BI solutions.
ScienceSoft delivers cloud-native, real-time web and mobile apps, web servers, and custom APIs ~1.5–2x faster than other software developers.
ScienceSoft's PHP developers helped to build Viber. Their recent projects: an IoT fleet management solution used by 2,000+ corporate clients and an award-winning remote patient monitoring solution.
ScienceSoft's developers use Go to build robust cloud-native, microservices-based applications that leverage advanced techs — IoT, big data, AI, ML, blockchain.
Front-end programming languages
ScienceSoft leverages code reusability Angular is notable for to create large-scale apps. We chose Angular for a banking app with 3M+ users.
ScienceSoft achieves 20–50% faster React development and 50–90% fewer front-end performance issues due to smart implementation of reusable components and strict adherence to coding best practices.
ScienceSoft’s achieves 20–50% cost reduction for iOS projects due to excellent self-management and Agile skills of the team. The quality is never compromised — our iOS apps are highly rated.
There are award-winning Android apps in ScienceSoft’s portfolio. Among the most prominent projects is the 5-year-long development of Viber, a messaging and VoIP app for 1.8B users.
ScienceSoft cuts the cost of mobile projects twice by building functional and user-friendly cross-platform apps with Xamarin.
ScienceSoft reduces up to 50% of project costs and time by creating cross-platform apps that run smoothly on web, Android and iOS.
Integration of a market-available payment gateway costs around $20K–$100K, while the implementation a custom payment gateway requires $100K–$300K in investments.
From ScienceSoft’s experience, each payments integration case is unique, so the cost factors vary for different customers. Below, we outline general factors that affect cost and duration of payments integration projects.
Integration cost factors
- The chosen type of an online payment gateway (hosted or self-hosted), which defines the integration pattern.
- The number and specifics of solutions (web and/or mobile applications, corporate software, external systems) to be integrated and the number of integration points.
- (for a custom payment gateway) Solution complexity and requirements for the UX/UI of a checkout page.
- The required modifications of the integrated apps, both on the technical level and on the app logic level.
- The chosen sourcing model (in-house, outsourced).
Operational cost factors
- Performance, availability, scalability, security requirements for the integrated system, which defines data processing and storage capacity and IT infrastructure security mechanisms.
- (for a market-available payment gateway) Setup fees for a gateway and a merchant account.
- (for a self-hosted payment gateway) The cost of maintaining PCI DSS compliance.
ScienceSoft is a global IT consulting and software development company headquartered in McKinney, Texas. We provide end-to-end application integration services to help companies integrate payment functionality in their web and mobile apps and seamlessly accept digital payments from customers. In our payments integration projects, we employ robust quality management and data security management systems backed up by ISO 9001 and ISO 27001 certification.
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