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Payment App Development

How to Build a Successful Solution

ScienceSoft combines 23 years of experience in web dev and 17 years – in mobile development with 15-year practice in creating financial solutions to help companies design and build robust payment applications.

How to Build a Payment App - ScienceSoft
How to Build a Payment App - ScienceSoft

Payment Application Development: Summary

Payment application development helps companies focused on payments provide their customers with a fast and convenient way of sending and receiving digital payments. Custom payment apps offer comprehensive functionality for funds management, support all required payment methods and currencies, provide advanced security of customer’s personal and payment data, and can be easily evolved with new features.

Key project steps: Payment needs analysis, requirements engineering, project planning, payment application design, tech stack selection, development, integration, quality assurance, deployment, support and evolution of the payment app.

Timelines: 6–11 months on average.

Cost: $150K–$2M+, depending on the type of a payment app.

Team: a project manager, a business analyst, a solution architect, a UX designer, a UI designer, a front-end developer, a back-end developer, a DevOps engineer, a QA engineer.

ScienceSoft can provide all necessary competencies to help companies roll out reliable, secure, and visually appealing payment applications that ensure seamless payment experience for their target audience and drive high ROI.

Types of Payment Applications

ScienceSoft is ready to help you design and develop the type of a payment app that fits the specifics of your business best.

A bank-based payment app

Employs existing banking infrastructure to process and settle digital payments in fiat currencies.

Best for: established traditional banks, neobanks.

A standalone payment app

Relies on non-banking payment processing infrastructure, enables fast and cost-effective funds transfer between the app’s users.

Best for: fintech startups focused on payments, including crypto startups.

A social-media-centric payment app

Provides a digital wallet embedded in the social media platform, allows for instant payments between the social network users.

Best for: social media companies.

A mobile-OS-based payment app

Offers a digital wallet built upon a mobile OS for NFC- and QR-code-enabled offline payments and convenient online payments.

Best for: mobile device manufacturers.

A Sample Architecture of a Payment Application

Sample Architecture of a Payment Application - ScienceSoft

Payment applications ScienceSoft delivers typically comprise:

  • Web and/or mobile interface for end users to interact with the application (make and accept payments, check the account balance, monitor spend, etc.).
  • A payment processing system to verify a user’s personal and payment information, trigger funds settlement and control its progress.
  • PCI DSS compliant data storage to ensure the security of cardholders’ sensitive data and enforce proper data retention and deletion policies.

To operate properly, a payment app needs to ensure a seamless payment data flow to the payment processing networks (e.g., the ACH network, SWIFT, VISA / MasterCard / American Express card network). Bank-based payment apps rely on direct integration between the bank’s existing payment processing system and the payment processing networks. Other payment apps usually employ banking APIs to integrate their payment processing system with a chosen acquiring bank, validate the required personal and payment information of the users, and streamline its further transfer to the processing networks and other banks.

Note! Cryptocurrency payment processing requires integration with dedicated blockchain networks of the crypto coins that a payment app supports. ScienceSoft recommends employing ready-to-use cryptocurrency APIs (e.g., Coinbase API, CoinGate API) to streamline the connection of a payment app to the required blockchain networks.

Additionally, a payment app can be integrated with an accounting system of the app owner to instantly record data on the received transaction fees. The solution may also be connected to the data analytics system to share relevant data required to analyze the app users’ payment behavior.

Key Features of a Payment Application

From ScienceSoft’s experience, companies looking to develop a payment application usually expect the solution to cover the following functionality:

Payments and money transfers

  • Sending and receiving domestic and cross-border payments, including recurring, split, and advance payments.
  • Real-time payment processing.
  • Support for various payment methods, including debit/credit cards, e-wallets, bank transfers, etc.
  • Multi-currency payments, including cryptocurrency payments.
  • Online and offline QR-code-based payments.
  • NFC-enabled onsite mobile payments.
  • P2P money transfers within the payment system’s network using an email address, a phone number, or an account ID of a money recipient.
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Payment transactions tracking

  • A full history of payment transactions.
  • Real-time tracking of inbound and outbound payment transactions by status, period, amount, and more.
  • Configurable user notifications, e.g., on successful or failed automated payments, due payments, upcoming payment card expiry.
  • (for crypto payments) An immutable record of payment transactions in the blockchain ledger.
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Spend management

  • Configurable budget and saving goals for a particular period (e.g., a week, a month, a quarter) or category (e.g., food, clothing, transportation, entertainment).
  • Real-time analysis of current vs. planned spend.
  • Alerts on actual expenses exceeding the pre-set threshold.
  • Automated generation of spend reports (by period, category, transaction amount, etc.).
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Funds management

  • Filling up the account balance using a bank transfer or a debit/credit card.
  • Scheduled and ad hoc payouts to the bank account or a debit/credit card.
  • Automated updates of the account balance.
  • Automated conversion of the account balance and transferred amounts to the user-defined fiat currency or cryptocurrency.
  • Support for in-app currency exchange transactions.
  • Configurable dashboards with up-to-date currency exchange rates.
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Account management for app users

  • Adding, saving, and updating personal/business info, billing details, including tax IDs, bank account and payment card details, etc.
  • Creating custom templates for recurring payments, such as utilities, rent, telecom, insurance, assigning a preferred payment method.
  • A digital assistant to help app users solve technical, transactional, security issues.
  • End-to-end audit trail of all account activities.
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Billing and invoicing

  • Tracking paid and outstanding invoices.

For businesses:

  • Automatically generating and submitting multi-language invoices to customers to initiate the collection of due payments.
  • Automated generation of region-specific e-invoices.
  • Signing invoices using an electronic signature.

For customers:

  • In-app bill payments.
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Security and compliance

  • Multi-factor authentication, including biometric authentication (e.g., facial or fingerprint recognition).
  • Data encryption.
  • AI-powered fraud detection.
  • Geography-based KYC verification.
  • Compliance with PCI DSS, PSD2 and GDPR (for the EU), other relevant global, country- and industry-specific regulations.
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A Roadmap to Payment Application Development

Below, ScienceSoft describes the essential steps we take to introduce a reliable and secure payment applications tailored to the clients’ unique requirements.

Analysis and requirements engineering

Duration: 1–3 weeks

At this stage, ScienceSoft’s consultants:

  • Communicate with key project stakeholders to discuss the payment app vision or discuss payment handling needs.
  • Introduce a detailed list of requirements for the solution, which describes:
  • The type of a payment app.
  • The required platform to base a payment app on (web, mobile, or both).
  • Functional capabilities a payment app is expected to provide, e.g., support for particular payment methods (cards, bank transfer, e-wallet, etc.), currencies (fiat and crypto), payment models (e.g., recurring payments, split payments), and more.
  • The data the app should be able to process (customers’ personal information, credit card data, crypto wallet address, etc.).
  • Requirements for the app’s UX and UI.
  • Non-functional requirements, including security and compliance requirements (e.g., AML/KYC requirements to prevent payment fraud, PCI DSS requirements for secure credit card payments processing, and more).


Project planning

Duration: 1–2 weeks

The accurate planning of payment app development can substantially reduce project timelines and prevent operational and financial risks. During this stage, ScienceSoft’s team:

  • Defines objectives, KPIs, and milestones for the project.
  • Determines project deliverables, duration, and budget.
  • Forms the project team and designs collaboration workflows.
  • Outlines possible project risks, defines a risk mitigation strategy and plan.
  • Estimates the expected TCO and ROI of the payment application.


Payment application design

Duration: 3–6 weeks
  • This step involves:

  • Designing the architecture of a payment app:
    • Creating a detailed description of how the app’s functional modules and a database should perform.
    • Determining integration approaches between the app’s components.
  • Introducing an optimal feature set for a payment application, including security and compliance features.
  • Designing UX and UI for the required user roles, such as individual users, corporate users, app admins:
    • Conducting UX research to understand the behavior of the app’s target audience.
    • Describing user interactions with the app, creating functional wireframes and content layouts.
    • UX prototyping.
    • Designing the visual appearance of the app and introducing UI mockups.
  • Providing a payment app integrations plan with the required payment processing networks, suggesting optimal ready-to-use integration solutions (particular open banking APIs, crypto APIs, etc.), if needed.


Tech stack selection

Duration: 2–3 weeks
  • When selecting techs and tools for payment app implementation, ScienceSoft adheres to the following practices:

  • We rely on best-performing technologies and tools to ensure the high quality of the application.
  • We compare possible techs and tools in the context of the client's priorities (e.g., prompt development, minimized project cost, etc.) and form an optimal tech stack with the client’s goals in mind.
  • We employ platforms, frameworks, and ready-made components where possible to streamline payment app development and optimize project cost.


Payment application implementation

Duration: 5–8+ months, depending on the solution’s complexity

The implementation of a payment application with ScienceSoft usually includes the following stages:

1. Development

  • Establishing development and delivery automation environments (CI/CD, container orchestration, etc.).
  • Creating the server-side code of a payment app.
  • Developing role-based user interfaces.
  • Implementing a PCI DSS compliant database.
  • Performing unit tests in parallel with coding.

2. Integration with required systems

  • (for bank-based payment apps) App integration with a bank’s payment processing system.
  • (for other payment apps) App integration with the required payment processing networks using banking APIs and/or crypto APIs.

3. Quality assurance

  • Designing a test strategy, a test plan, test cases and checklists.
  • Writing and running automated test scripts, if relevant.
  • Conducting functional, including integration, and non-functional testing.
  • Fixing defects revealed during testing.

4. Deployment

  • Configuring the payment app’s infrastructure, backup and recovery procedures.
  • Implementing infrastructure security tools (authorization controls for APIs, DDoS protection algorithms, firewalls, IDSs / IPSs, etc.).
  • Deploying the payment application in the production environment.


Support and evolution (optionally)

Duration: continuous

ScienceSoft offers continuous monitoring and optimization of the payment application to ensure its stable performance, compliance with relevant data security standards and regulations, and ability to provide smooth payment experience for end users. We can evolve the app by adding new features and perfecting its non-functional capabilities.



Consider Professional Services to Build a Payment Application

ScienceSoft applies 33 years of experience in software development and 15-year expertise in implementing financial solutions to provide companies with:

Consulting on payment app development

  • Market and competition analysis.
  • Payment app conceptualization.
  • Defining product differentiation and Unique Selling Proposition (USP).
  • Optimal feature set, architecture design, UX and UI design, and tech stack for a payment app.
  • A plan of integrations with the required systems.
  • Security and compliance consulting.
  • Providing a payment app implementation plan, including a risk mitigation plan.

End-to-end payment app implementation

  • Payment app idea productization and brand design.
  • Architecture design.
  • Payment app development.
  • Developing APIs to expand the app’s integration capabilities.
  • App integration with the required systems.
  • Quality assurance.
  • Support and evolution of the payment app (if required).

Why ScienceSoft for payment app development?

  • In web development since 1999 and in mobile development since 2005.

  • 19 years in cybersecurity to ensure world-class protection of a payment application.
  • In-house compliance experts to guarantee payment app compliance with relevant global, country- and industry-specific standards and regulations.
  • Practical knowledge of 30+ industries, including BFSI and fintech.
  • A mature quality management system and customer data safety backed up by ISO 9001 and ISO 27001 certificates.
  • Listed among the Americas’ Fastest-Growing Companies 2022 by Financial Times.

Typical Roles on ScienceSoft’s Payment App Development Teams

Project Manager

Creates a project plan, prioritizes the scope of work and monitors its execution, coordinates communication between the team members, reports the progress to the stakeholders.

Business Analyst

Analyzes needs and expectations of a client/target users and translates them into functional and non-functional requirements for the payment application.

Solution Architect

Designs the architecture of the payment application and its integration points with the required systems.

UX Designer

Performs UX research, designs user interactions with a payment application, conducts usability testing.

UI Designer

Creates the style of the user-facing interfaces and introduces a UI kit for user interface development.

Front-end Developer

Delivers UI of a payment app and fixes defects found by the QA team.

Back-end Developer

Delivers the code of the app’s back end, integrates the solution with relevant systems, and fixes defects found by the QA team.

DevOps Engineer

Containerizes payment app’s components, configures CI/CD pipelines for streamlined app development, testing, and release.

Quality Assurance Engineer

Creates and implements a test strategy, a test plan, and test cases to validate the quality of the payment app against the quality requirements defined in the project plan.

Payment App Development: A Success Story by ScienceSoft

Development of a Mobile Payment Application for 18M+ E-wallets

Development of a Mobile Payment Application for 18M+ E-wallets

ScienceSoft designed and built a full-fledged iOS app for mobile payments. Our team created convenient app’s UX and clear UI to ensure smooth payment experience for end users. We implemented functionality for:

  • Instant payments on popular categories (home utilities, telecoms, leisure, etc.) using bank cards and eMoney.
  • NFC-enabled onsite payments.
  • Transactions and account balance tracking.
  • User authentication, and more.

Sourcing Models for Payment Application Development

Perks of Payment App Development with ScienceSoft

Prompt development

We guarantee a quick project start (1-2 weeks), frequent releases (every 2-3 weeks), and apply established Lean, Agile and DevOps practices to ensure the implementation of a payment application on time and within budget.

Transparent collaboration

We define custom sets of KPIs, track project progress, and submit regular reports to ensure service quality and transparency.

Fast payback

We rely on an iterative approach to payment app development to introduce the fundamental functions first and speed up payback.

Guaranteed compliance

We ensure the payment application compliance with PCI DSS, AML/KYC regulations, other relevant global, country- and industry-specific standards and regulations.

Our Customers Say

We chose ScienceSoft as a technology partner for the mobile banking development project for both iOS and Android platforms. We were pleased with the outcomes of the project, as well as with the collaboration mode. ScienceSoft brought to the table substantial expertise in mobile application development and explicitly customer-centered approach to the application design. Besides, they proved to be a reliable and agile technology partner. We especially appreciate their professional approach to security issues, which were among our main concerns due to strict regulations.

Khalid Ahadov, Executive Director at Unibank

ScienceSoft’s Tech Stack for Payment Application Development

In payment app development projects, ScienceSoft’s team usually relies on the following tools and technologies:

Back-end programming languages

Front-end programming languages



JavaScript frameworks



Databases / data storages


Microsoft SQL Server



Cloud databases, warehouses and storage


Amazon Relational Database Service
Amazon S3
Amazon DocumentDB
Amazon ElastiCache


Azure SQL Database
Azure Data Lake
Azure Blob Storage

Google Cloud Platform

Google Cloud SQL
Google Cloud Datastore

Real-time data processing

Apache Kafka Streams
Amazon Kinesis
Azure Event Hubs



Red Hat OpenShift
Apache Mesos


HashiCorp Terraform
HashiCorp Packer

CI/CD tools

AWS Developer Tools
Azure DevOps
Google Developer Tools
GitLab CI/CD



Architecture designs and patterns

Microservices-based architecture

Cloud-native architecture

Reactive architecture

Service-oriented architecture (SOA)


Traditional 3-layer architecture

Cost Factors of Payment Application Development

Building a bank-based mobile payment app of average complexity costs around $150K, while developing a comprehensive standalone payment app with an independent payment processing system at its core may require $2M+ in investments.

As you see, the costs of building a payment app vary greatly from case to case. Below, ScienceSoft lists the major factors that affect project costs:

Core cost factors

  • The type of a payment app (determines the spend on integrations with payment processing networks).
  • The number and complexity of the app’s features.
  • The platform to base the app on (web, mobile, or both).
  • (for mobile payment apps) Supported mobile platforms (iOS, Android).
  • The number of user roles and specific UX and UI requirements for each role.
  • Performance, scalability, availability, security requirements for the app.

Operational cost factors

  • License fees for cloud services, ready-made app components (e.g., KYC/AML verification services, messaging services), integration components (banking APIs, crypto APIs), security tools.
  • Maintenance of PCI DSS compliance, including annual PCI audits.
  • Payment application support services.


About ScienceSoft

ScienceSoft is an international IT consulting and software development company headquartered in McKinney, Texas. We provide end-to-end application development services to help companies design and build reliable and secure payment apps. In our payment software development projects, we employ robust quality management and data security management systems backed up by ISO 9001 and ISO 27001 certifications.