Payment Gateway Development from A to Z

Having 34 years of experience in custom software development and 20 years in cybersecurity, ScienceSoft delivers reliable and secure payment gateways to help business in 30+ industries accept digital payments from their customers.

Payment Gateway Development - ScienceSoft
Payment Gateway Development - ScienceSoft

Payment Gateway Development: Summary

Payment gateway development helps companies introduce custom payment functionality in their web and/or mobile applications. Custom payment gateways support all required payment methods and currencies, offer advanced security of customer’s personal and payment data, seamlessly integrate with customer-facing apps and payment processing systems, and can be easily evolved with new features.

Key project steps: feasibility study, payment gateway design, project planning, tech stack selection, payment gateway development and QA, deployment, integration, support and evolution (optionally).

Timelines: 6–11 months on average.

Cost: end-to-end payment gateway development may cost from $100,000 to over $300,000, depending on the solution’s complexity.

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

With 750+ talents on board, ScienceSoft provides all necessary skills to cover the end-to-end development of a custom payment gateway and ensure its compliance with relevant security standards.

A Sample Architecture of a Payment Gateway by ScienceSoft

Below, ScienceSoft shares a sample architecture of payment gateways we create, describes essential solution integrations and payment handling flow.

Architecture of a Payment Gateway - ScienceSoft

An online payment gateway serves as a bridge that enables instant and secure transfer of a customer’s personal and payment information between an application that hosts a checkout page (e.g., a merchant’s website, a customer portal) and one or several payment processing systems. The latter can be provided by a financial institution (an acquiring bank), independent payment processing providers (e.g., PayPal, Authorize.Net, Stripe, BitPay), or the company (in case of relying on in-house payment processing). The payment gateway verifies sensitive data provided by a customer (purchasing details, billing address, a credit card number, etc.), encrypts and stores it in a PCI DSS compliant storage. Once a payment transaction is authorized in a payment processing system, approved in a payment processing network (e.g., ACH network, a card network, a crypto coin’s network), and settled between the customer’s bank and a company’s bank, a payment gateway automatically communicates payment success or decline to the customer.

A payment gateway integrates with an accounting system to instantly transfer data on the successful payments and receive triggers to timely charge due payments (e.g., recurring payments). Additionally, the solution may be connected to a data analytics system to share relevant data required to analyze cash inflow and customer payment behavior.

If you plan to monetize your custom payment gateway by offering it to other companies for a fee, the solution can be equipped with ready-to-use APIs to enable prompt and easy integration with customer-facing apps of the authorized merchants.

When to Opt for a Custom Payment Gateway

From ScienceSoft’s experience, companies looking to implement payment functionality in their web and/or mobile application often have doubts about whether they should rely on a market-available payment gateway or build their own custom solution. So far, integrating a prebuilt payment gateway remains a more popular option, as it offers a fast and easy way to enable digital payments. However, an off-the-shelf gateway is not always the most economically feasible option. Prebuilt gateways can bring high fees for third-party payment gateway providers’ services. They may also require substantial efforts on customization and establishing smooth integration with the required apps.

ScienceSoft suggests opting for a custom payment gateway in the following cases:

You need a payment gateway providing specific capabilities, e.g., support for all required payment methods, including crypto payments, sophisticated recurring payments, AI-powered fraud detection, or on-demand scalability to handle the growing amount of payment transactions during peak times.

You need a solution that can be easily evolved with new functionality as your business grows or transforms.

You want to smoothly and cost-effectively integrate a payment gateway with your existing software (e.g., an ecommerce website, a customer portal, a mobile banking app, an accounting system).

You want to monetize your payment gateway by allowing other companies to use it for a fee. For example, if you own an ecommerce marketplace, you can offer the merchants to accept payments via your custom-made payment gateway and charge them for this service.

Note: If you choose to develop a custom payment gateway, you take full responsibility for obtaining PCI DSS compliance. Here at ScienceSoft, we are ready to provide a full scope of PCI compliance services to help you implement and maintain proper storage, processing, and transfer of cardholder data according to PCI standards.

How To Develop A Payment Gateway: Key Steps

Below, ScienceSoft’s experts share a sample roadmap of a payment gateway development project and outline best practices to maximize ROI from the project.


A feasibility study


Payment gateway design and project planning


Tech stack selection


Payment gateway development


Payment gateway deployment


Integration with other systems


Support and evolution of a payment gateway (optionally)

Professional Payment Gateway Development Services

Having 34 years of experience in software development and 18-year expertise in fintech, ScienceSoft can help with:

Consulting on payment gateway implementation

  • Analyzing your business needs and eliciting requirements for a payment gateway.
  • Designing an optimal architecture, feature set, and tech stack for a payment gateway.
  • Preparing a plan of integrations with the required systems.
  • Consulting on security and compliance.
  • Delivering a roadmap for payment gateway implementation, including cost and time estimates and a risk mitigation plan.

End-to-end payment gateway development

  • Analyzing your payment handling needs.
  • Conceptualizing the payment gateway.
  • Architecture design.
  • Payment gateway development.
  • Integrating the payment gateway with the required systems.
  • Implementing security policies, procedures, and controls for cardholder data to achieve PCI DSS compliance.
  • Quality assurance.
  • Support and evolution (if required).

Why Choose Payment Gateway Development with ScienceSoft

  • Since 1989 in software development.
  • Since 2003 in cybersecurity to ensure world-class protection of your payment gateway solution.
  • In-house compliance experts to ensure that your payment gateway meets PCI DSS requirements and other essential region- and industry-specific standards and regulations.
  • 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.
  • For the second straight year, ScienceSoft USA Corporation is listed among The Americas’ Fastest-Growing Companies by the Financial Times.

Typical Roles on ScienceSoft’s Payment Gateway Development Teams

Project Manager

Plans the payment gateway project (goals, timeline, budget), prioritizes the scope of work and monitors its execution, coordinates the project team, reports the progress to the stakeholders.

Business Analyst

Elicits and documents functional and non-functional requirements for the payment gateway, analyzes technical capabilities and limitations of the existing IT infrastructure.

Solution Architect

Designs the architecture of the payment gateway solution, including integration points with the required systems.

UX/UI Designer

Designs the UX and UI of a customer-facing checkout page and the back-office UI to monitor the payment gateway’s performance.

DevOps Engineer

Containerizes the components of the payment gateway solution and configures CI/CD pipelines for streamlined testing and facilitated deployment.

Back-end Developer

Delivers the back end of the payment gateway (including integration API code) and fixes defects reported by QA engineers.

Front-end Developer

Delivers the UI of a customer-facing checkout page and an admin panel and fixes defects reported by QA engineers.

QA Engineer

Designs and implements a test strategy, a test plan, and test cases to perform functional (incl. integration) and non-functional testing (e.g., security, performance, and usability testing).

Sourcing Models for Payment Gateway Development

Payment Gateway Development: A Success Story by ScienceSoft

Payment Gateway Development for a Messaging App with 900M+ Active Users

Payment Gateway Development for a Messaging App with 900M+ Active Users

ScienceSoft designed and implemented a custom payment gateway to provide seamless payment experience for 900M+ active users of Viber, a messaging app that operates in more than 190 countries. Particularly, our team:

  • Created the checkout page fully compatible with Firefox, Chrome, Safari, Android and iOS browsers, and more.
  • Integrated the payment gateway with PayPal and a card network (Visa, MasterCard, American Express) to support the most popular payment methods.
  • Designed a payment module architecture that enables fast and easy integration of new payment methods.
  • Implemented a range of security tools to protect the system against XSS and CSRF attacks.

ScienceSoft’s Tech Stack for Payment Gateway Development

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

Databases / data storages


Microsoft SQL Server

Our Microsoft SQL Server-based projects include a BI solution for 200 healthcare centers, the world’s largest PLM software, and an automated underwriting system for the global commercial insurance carrier.


We’ve implemented MySQL for Viber, an instant messenger with 1B+ users, and an award-winning remote patient monitoring software.


ScienceSoft's team has implemented Oracle for software products used by GSK and AstraZeneca. We’ve also delivered Oracle-based SCM platform for Auchan, a retail chain with 1,700 stores.


ScienceSoft has used PostgreSQL in an IoT fleet management solution that supports 2,000+ customers with 26,500+ IoT devices. We’ve also helped a fintech startup promptly launch a top-flight BNPL product based on PostgreSQL.



ScienceSoft used MongoDB-based warehouse for an IoT solution that processed 30K+ events/per second from 1M devices. We’ve also delivered MongoDB-based operations management software for a pharma manufacturer.

Cloud databases, warehouses and storage


Amazon Redshift

We use Amazon Redshift to build cost-effective data warehouses that easily handle complex queries and large amounts of data.

Find out more
Amazon DynamoDB

We use Amazon DynamoDB as a NoSQL database service for solutions that require low latency, high scalability and always available data.

Find out more


Azure Cosmos DB

We leverage Azure Cosmos DB to implement a multi-model, globally distributed, elastic NoSQL database on the cloud. Our team used Cosmos DB in a connected car solution for one of the world’s technology leaders.

Find out more
Azure SQL Database

Azure SQL Database is great for handling large volumes of data and varying database traffic: it easily scales up and down without any downtime or disruption to the applications. It also offers automatic backups and point-in-time recoveries to protect databases from accidental corruption or deletion.

Google Cloud Platform

Google Cloud Datastore

We use Google Cloud Datastore to set up a highly scalable and cost-effective solution for storing and managing NoSQL data structures. This database can be easily integrated with other Google Cloud services (BigQuery, Kubernetes, and many more).

Back-end programming languages

Microsoft .NET


19 years





Our .NET developers can build sustainable and high-performing apps up to 2x faster due to outstanding .NET proficiency and high productivity.

Find out more


25 years





ScienceSoft's Java developers build secure, resilient and efficient cloud-native and cloud-only software of any complexity and successfully modernize legacy software solutions.

Find out more


10 years





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.

Find out more


10 years



ScienceSoft delivers cloud-native, real-time web and mobile apps, web servers, and custom APIs ~1.5–2x faster than other software developers.

Find out more


16 years





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.

Find out more


4 years

ScienceSoft's developers use Go to build robust cloud-native, microservices-based applications that leverage advanced techs — IoT, big data, AI, ML, blockchain.

Find out more

Front-end programming languages




21 years





ScienceSoft uses JavaScript’s versatile ecosystem of frameworks to create dynamic and interactive user experience in web and mobile apps.

Find out more

JavaScript frameworks

Angular JS


13 years



ScienceSoft leverages code reusability Angular is notable for to create large-scale apps. We chose Angular for a banking app with 3M+ users.

Find out more
React JS



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.

Find out more

ScienceSoft uses Meteor for rapid full-stack development of web, mobile and desktop apps.


By using a lightweight Vue framework, ScienceSoft creates high-performant apps with real-time rendering.


With Next.js, ScienceSoft creates SEO-friendly apps and achieves the fastest performance for apps with decoupled architecture.


When working with Ember.js, ScienceSoft creates reusable components to speed up development and avoid code redundancy.




16 years





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.

Find out more


14 years





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.

Find out more


11 years





ScienceSoft cuts the cost of mobile projects twice by building functional and user-friendly cross-platform apps with Xamarin.

Find out more
Apache Cordova

ScienceSoft uses Cordova to create cross-platform apps and avoid high project costs that may come with native mobile development.

Progressive Web Apps

ScienceSoft takes the best from native mobile and web apps and creates the ultimate user experience in PWA.

React Native


8 years



ScienceSoft reduces up to 50% of project costs and time by creating cross-platform apps that run smoothly on web, Android and iOS.

Find out more

ScienceSoft will save you from double or even triple expenses associated with platform-specific coding by creating cross-platform apps in Flutter.


With Ionic, ScienceSoft creates a single app codebase for web and mobile platforms and thus expands the audience of created apps to billions of users at the best cost.

Real-time data processing




CI/CD tools


Cost Factors of Payment Gateway Development

Based on ScienceSoft's experience in payment software development projects, we defined the general cost factors that apply to the majority of payment gateway development use cases:

  • Requirements to the functional capabilities of a payment gateway, its performance, scalability, availability, and security.
  • The number and complexity of integrations with relevant software (customer-facing web and mobile apps, payment processing systems, accounting software, data analytics solutions, etc.).
  • The required modifications of the integrated web and mobile apps, both on the technical level and on the app logic level.
  • Whether the payment gateway is going to be monetized or not: the former calls for the ready-to-use integration API development.
  • Requirements for the appearance, structure, and contents of a checkout page.
  • The need to obtain and maintain PCI DSS certification.


About ScienceSoft

ScienceSoft is an international payment gateway software development company headquartered in McKinney, Texas. We provide end-to-end custom software development services to help companies design and build reliable and secure payment gateway solutions tailored to their specific payment handling needs. In our payment gateway development projects, we employ robust quality management and data security management systems backed by ISO 9001 and ISO 27001 certification.