Payment Gateway Integrator You Can Trust
With proven integration expertise and a keen grasp of financial workflows, we deliver payment systems that maximize uptime, accelerate growth, and adapt to your business requirements.
15+years of experience in fintech and banking app development
100+successfully launched financial products
800+Experienced full-time employees
Our Payment Gateway Integration Services
Modern digital products depend on steady transaction flows. We deliver payment infrastructure that boosts efficiency, increases transaction reliability, and keeps your operations running smoothly while connecting your apps and financial systems.

Gateway API integration
Payment methods enablement
Checkout implementation
Recurring billing integration
Payment orchestration and routing
Compliance-ready implementation
Business Systems We Connect Through Payment Integration
Payment infrastructure fuels your business. Our integrations guarantee your orders, subscriptions, and finances are flawlessly connected, so every transaction is tracked and every record is current, driving operational excellence.
Checkout
Build seamless web and mobile checkout flows so your customers pay in seconds, receive instant confirmation, and your backend systems stay perfectly in sync to avoid order or payment errors.
E-commerce platforms and shopping carts
Connect payment gateways across your shopping cart, catalog, tax, and discount systems, and launch faster, sell smarter, and deliver a frictionless checkout every time.
Order management systems
Ensure operational consistency between transaction status and fulfillment processes, preventing problematic scenarios such as shipped orders without confirmed payments or completed transactions that never trigger shipment workflows.
Billing systems
Automate every recurring payment with integrations that prevent failed charges, trigger billing retries, and keep revenues steady, reducing manual effort and missed collections.
Marketplaces and vendor platforms
Simplify complex marketplace models: our payment integrations automate payouts, manage split payments, and enable vendor onboarding, so you keep every transaction visible and every partner happy.
Accounting and finance systems
Sync payment and accounting platforms so every settlement, fee, and payout posts automatically, speeding up financial reconciliation and giving you instant, trustworthy records for smarter decisions.
Payment Gateway Integration Models
Different payment architectures balance speed, user-experience control, and compliance. We help organizations select and implement the best-fit integration model for their needs. Our engineers support multiple gateway integration approaches, from fast-deployment models for rapid launch to fully customized integrations that give businesses complete control over payment flows.
Hosted checkout
- Time-to-launch: Fastest path to production, ideal for rapid deployment with minimal engineering effort.
- PCI implications: Lowest PCI scope, as all sensitive card data is handled entirely by the payment provider.
- UX flexibility: Limited control over the checkout experience, with branding options available but core flow managed by the gateway.
Embedded payment UI
- Time-to-launch: Fast and predictable, with slightly more implementation effort than hosted models.
- PCI implications: Low to moderate scope; tokenized elements ensure sensitive data does not pass through your servers.
- UX flexibility: High control over layout, validation, and user experience, enabling a more cohesive and branded checkout flow.
Direct API integration
- Time-to-launch: Moderate, requiring deeper engineering effort, testing, and coordination across payment scenarios.
- PCI implications: Higher PCI exposure if card data is processed directly, requiring careful architectural design to minimize scope.
- UX flexibility: Maximum control over payment logic, user experience, and edge-case handling across the entire transaction lifecycle.
Mobile payment gateway integration
- Time-to-launch: Fast to moderate, depending on platform requirements, SDK usage, and supported payment methods.
- PCI implications: Typically low when using provider Software Development Kits (SDKs) and tokenization, with secure implementation practices still required.
- UX flexibility: High control over in-app payment flows, with support for native experiences such as Apple Pay and Google Pay to improve usability and conversion.
Architecture That Prevents the Painful Stuff
Payment integration issues, such as duplicate charges or lost events, are common. We design architectures to ensure payment flows are consistent and resilient in real conditions.
Payment Gateway Integration Process We Follow
Integrating payment infrastructure requires careful planning, architecture design, and controlled implementation. Our structured approach ensures that integrations are technically reliable, compliant with payment regulations, and aligned with your operational workflows.
Discovery and requirements analysis
Timeline: 1–2 weeks
We begin by evaluating your existing systems and defining integration requirements in detail.
- Conduct stakeholder interviews to gather requirements, including supported payment methods, regions, transaction volumes, checkout UX expectations, and security needs.
- Assess regulatory obligations, including PCI DSS and other relevant compliance requirements.
- Analyze current infrastructure, integrations, and data flows to understand system constraints and define how payment data will move between systems.
Project planning
Timeline: 1–2 weeks
During this stage, we establish a clear project roadmap and delivery framework.
- Define the integration scope, deliverables, project milestones, and success KPIs.
- Estimate timelines, budget, and expected total cost of ownership.
- Identify potential risks and develop mitigation strategies to maintain predictable implementation.
Integration architecture design
Timeline: 2–5 weeks
Next, we design the payment architecture and integration model best suited to your platform.
- Select the optimal gateway integration approach, such as hosted checkout, embedded UI, or direct API integration.
- Design the system architecture, APIs, data exchange mechanisms, and operational workflows.
- Optionally design custom checkout experiences aligned with your UX and branding requirements.
Technology stack selection
Timeline: ~1 week
We determine the most suitable technologies and integration tools for the implementation.
- Evaluate available frameworks, SDKs, APIs, and infrastructure components.
- Compare options against business requirements, scalability goals, and security standards.
- Select the optimal stack to support long-term maintainability and performance.
Integration implementation and testing
Timeline: 2–8 weeks (depending on complexity)
At this stage, we implement the integration and thoroughly validate its reliability and security.
- Develop or configure the payment gateway integration using APIs, SDKs, or custom middleware.
- Implement payment workflows within checkout systems, backend services, and connected platforms.
- Perform functional, integration, performance, and security testing to ensure production readiness.
Payment integrations don’t have to be slow or risky. Tell us about your current platform, and we’ll outline the most efficient and reliable path to integration.
Gateways and Platforms We Connect
Payment gateways and PSPs
Subscription and billing platforms
Accounting and finance systems
Banking and Open Banking APIs
Security Practices Behind Reliable Payment Integrations
Our payment integration prioritizes both security and user experience. We embed practical controls into the architecture to minimize data exposure, streamline compliance, and ensure responsible data handling across all systems involved.
PCI scope minimization strategy
We design payment flows to keep sensitive cardholder data out of your infrastructure by using hosted payment elements, tokenization, and gateway-managed processing. This reduces PCI compliance scope, lowers risk, simplifies compliance, and frees your team to focus on product development.
Secure storage and tokenization approach
Modern payment systems use tokenization to replace sensitive card details with secure, reusable tokens. We implement architectures that safely manage and scope tokens across all services, rotating them as needed to keep customer payment data protected while supporting features such as saved cards and recurring payments.
Logging and auditability
Transparent logging and traceability are critical for diagnosing payment issues and maintaining operational accountability. We design integrations with structured logs, traceable transaction identifiers, and audit-ready records so that every payment action, from authorization to refund, can be tracked and verified. This ensures finance, operations, and support teams can investigate issues quickly while maintaining a clear audit trail.
Data protection basics
Effective security often comes down to applying the right foundational controls. We implement practical safeguards, including encrypted communication, strict access controls, secure credential management, and protection against accidental data exposure in logs or analytics tools. These controls help reduce risk while preserving performance and usability across payment flows.
Awards and Recognitions
What Our Clients Say
Client feedback frequently highlights structured communication practices, periodic progress reporting, and alignment with agreed project objectives. Deliverables are typically documented and tracked, allowing stakeholders to monitor milestones and project outputs throughout the engagement.
Frequently Asked Questions About Payment Gateway Integrations
Integrating a payment gateway involves practical decisions about architecture, compliance, and operations. Below are concise answers to common questions organizations have when planning or implementing payment integrations.















Emerline is an important part of our strategic team!
Emerline has been our technology partner since late 2012. In the early years I thought that would be a short-term gap fill until I could afford to hire my own technical team in the US. But they have consistently met the demands of our growing company and helped us build what we believe is the industry's best solution option. Emerline provides high quality work, so much so that our platform's reliability and accuracy has been mentioned by our largest customer's internal vendor survey repeatedly. The individuals we work with aren't just contractors, they are an important part of our strategic Team and we enjoy working with them every day!
Emerline is an important part of our strategic team!
Emerline has been our technology partner since late 2012. In the early years I thought that would be a short-term gap fill until I could afford to hire my own technical team in the US. But they have consistently met the demands of our growing company and helped us build what we believe is the industry's best solution option. Emerline provides high quality work, so much so that our platform's reliability and accuracy has been mentioned by our largest customer's internal vendor survey repeatedly. The individuals we work with aren't just contractors, they are an important part of our strategic Team and we enjoy working with them every day!
President/CEO, CPG Data
USA
President/CEO, CPG Data
USA
Emerline has been the best development partner we’ve ever worked with!
Emerline has been the best development partner we’ve ever worked with. The team is very responsive and the quality is very high. They are always willing to do whatever is necessary to support development and customer support efforts. I would recommend them to anyone.
Emerline has been the best development partner we’ve ever worked with!
Emerline has been the best development partner we’ve ever worked with. The team is very responsive and the quality is very high. They are always willing to do whatever is necessary to support development and customer support efforts. I would recommend them to anyone.
CEO, Praxie
USA
CEO, Praxie
USA
We recommend Emerline as a trusted technology partner
We can confidently say that Emerline fully met our expectations, starting with providing high-quality advice on technologies that would improve our solution and continuing with their fast, high-quality implementation. Emerline has strong communication processes in place that kept us apprised of the project's stage and allowed us to discuss any issues on the go. The team was professional and promptly made adjustments when asked. We recommend Emerline as a trusted technology partner for developing telemedicine solutions and would choose to work with Emerline again regarding new projects.
We recommend Emerline as a trusted technology partner
We can confidently say that Emerline fully met our expectations, starting with providing high-quality advice on technologies that would improve our solution and continuing with their fast, high-quality implementation. Emerline has strong communication processes in place that kept us apprised of the project's stage and allowed us to discuss any issues on the go. The team was professional and promptly made adjustments when asked. We recommend Emerline as a trusted technology partner for developing telemedicine solutions and would choose to work with Emerline again regarding new projects.
Founder, Hello Ralphie
USA
Founder, Hello Ralphie
USA
We are very pleased and content with our relationship with Emerline
We are very pleased and content with our relationship with Emerline. We rely on their team for full-stack development of our platform. We respect the high technical caliber and dedication of the team assigned to our project. Emerline provided us with the scaling we needed to grow development capabilities from early-stage POC to now a globally deployed platform in the HR Teach space.
We are very pleased and content with our relationship with Emerline
We are very pleased and content with our relationship with Emerline. We rely on their team for full-stack development of our platform. We respect the high technical caliber and dedication of the team assigned to our project. Emerline provided us with the scaling we needed to grow development capabilities from early-stage POC to now a globally deployed platform in the HR Teach space.
CEO, Espresa
USA
CEO, Espresa
USA
We highly recommend Emerline as a technology partner
The Emerline team involved in the completion of our projects demonstrated a high level of responsiveness and support by solving issues and answering questions ASAP. They were diligent and proactively addressed the challenges that arose during the development process. Our cooperation ran smoothly and professionally, and Emerline quickly provided direct and correct advice when necessary. We highly recommend Emerline as a technology partner for large and complicated development projects that also delivers continuous cooperation with the provider on new projects.
We highly recommend Emerline as a technology partner
The Emerline team involved in the completion of our projects demonstrated a high level of responsiveness and support by solving issues and answering questions ASAP. They were diligent and proactively addressed the challenges that arose during the development process. Our cooperation ran smoothly and professionally, and Emerline quickly provided direct and correct advice when necessary. We highly recommend Emerline as a technology partner for large and complicated development projects that also delivers continuous cooperation with the provider on new projects.
VP Global IT, FUCHS Group
Germany
VP Global IT, FUCHS Group
Germany
Emerline helped us build an MVP into a full-fledged production platform — in 14 months
Emerline worked closely with us to take the best ideas from our MVP and integrate them with transactional capabilities for digital payments, workflow for job management, and funds transfers for cash advances. Our platform was built to service the roofing industry getting contractors paid faster so they can focus on growing their businesses and servicing their customers.
Emerline helped us build an MVP into a full-fledged production platform — in 14 months
Emerline worked closely with us to take the best ideas from our MVP and integrate them with transactional capabilities for digital payments, workflow for job management, and funds transfers for cash advances. Our platform was built to service the roofing industry getting contractors paid faster so they can focus on growing their businesses and servicing their customers.
Founder and CEO, SquareDash
USA
Founder and CEO, SquareDash
USA
They proved themselves reliable technology partners
Throughout our cooperation with Emerline, they proved themselves reliable technology partners. That’s why we trusted them with our new project — website migration to AEM and revamping our brand’s product catalog that we use across multiple websites — without any hesitation. The team always stayed in touch, providing regular feedback and progress updates. The cooperation was smooth, and the work on the project was completed in due time. They provided an efficient solution that allowed us to reduce infrastructure costs; with it, we didn’t have to depend on third-party vendors. Thanks, Emerline! We will definitely continue working with you.
They proved themselves reliable technology partners
Throughout our cooperation with Emerline, they proved themselves reliable technology partners. That’s why we trusted them with our new project — website migration to AEM and revamping our brand’s product catalog that we use across multiple websites — without any hesitation. The team always stayed in touch, providing regular feedback and progress updates. The cooperation was smooth, and the work on the project was completed in due time. They provided an efficient solution that allowed us to reduce infrastructure costs; with it, we didn’t have to depend on third-party vendors. Thanks, Emerline! We will definitely continue working with you.
IT Director
USA
IT Director
USA
Emerline exceeded expectations!
Redesigning our website wasn't just about updating our look — it was about building a stronger front door for the world to experience Miami’s economic story. As the official EDO for Miami-Dade, we knew the stakes were high. Emerline exceeded expectations. They were consistently organized, forward-thinking, and committed. In less than six months, we had a completely new platform — faster, smarter, and built to grow with us. We’re proud of what we built together!
Emerline exceeded expectations!
Redesigning our website wasn't just about updating our look — it was about building a stronger front door for the world to experience Miami’s economic story. As the official EDO for Miami-Dade, we knew the stakes were high. Emerline exceeded expectations. They were consistently organized, forward-thinking, and committed. In less than six months, we had a completely new platform — faster, smarter, and built to grow with us. We’re proud of what we built together!
President & CEO, Miami-Dade Beacon Council
USA
President & CEO, Miami-Dade Beacon Council
USA
The team gladly brought their expertise and delivered us a perfect solution to meet our customers’ business needs.
The Emerline team wasn’t scared of any challenges and managed to design a solution to cater to any analytical or supply chain tasks. Their enthusiasm and process transparency ensured seamless communication and prompt reaction to any adjustment or focus shift from our side. Their experience and dedication allowed them to provide the solution really fast. We highly recommend choosing Emerline as a development partner if you need a high-end solution for your business.
The team gladly brought their expertise and delivered us a perfect solution to meet our customers’ business needs.
The Emerline team wasn’t scared of any challenges and managed to design a solution to cater to any analytical or supply chain tasks. Their enthusiasm and process transparency ensured seamless communication and prompt reaction to any adjustment or focus shift from our side. Their experience and dedication allowed them to provide the solution really fast. We highly recommend choosing Emerline as a development partner if you need a high-end solution for your business.
Founder & CEO, Kontango
USA
Founder & CEO, Kontango
USA
We recommend Emerline as a reliable and skilled tech partner
Collaboration with Emerline was one of our best decisions! Their team quickly understood both the technical requirements and the industry-specific challenges we were trying to solve. We needed a secure, flexible platform that could support data-driven formulation across different industries, and Emerline delivered exactly that. Their team approached the task with professionalism, understood our goals, and built a solution that met both technical and user-facing needs.The result is a working platform that reduces manual work, speeds up R&D, and supports faster, smarter formulation processes across various industries. From day one, communication was smooth, timelines were clear, and we felt fully supported throughout the project. We highly recommend Emerline as a tech partner for your future initiatives.
We recommend Emerline as a reliable and skilled tech partner
Collaboration with Emerline was one of our best decisions! Their team quickly understood both the technical requirements and the industry-specific challenges we were trying to solve. We needed a secure, flexible platform that could support data-driven formulation across different industries, and Emerline delivered exactly that. Their team approached the task with professionalism, understood our goals, and built a solution that met both technical and user-facing needs.The result is a working platform that reduces manual work, speeds up R&D, and supports faster, smarter formulation processes across various industries. From day one, communication was smooth, timelines were clear, and we felt fully supported throughout the project. We highly recommend Emerline as a tech partner for your future initiatives.
FastFormulator Key Partner and Project Leader
USA
FastFormulator Key Partner and Project Leader
USA
Emerline demonstrated a deep understanding of the client's vision
Emerline demonstrated a deep understanding of the client's vision, delivering a functional MVP on time and within budget. The team was highly responsive to the client's needs and maintained clear communication throughout. Above all, their exceptional project management skills stood out.
Emerline demonstrated a deep understanding of the client's vision
Emerline demonstrated a deep understanding of the client's vision, delivering a functional MVP on time and within budget. The team was highly responsive to the client's needs and maintained clear communication throughout. Above all, their exceptional project management skills stood out.
CEO, Founder of Tribela GmbH
Germany
CEO, Founder of Tribela GmbH
Germany
The level of skill and quality of the developers is outstanding!
Emerline has been helping the client significantly improve their apps for 1.5 years. Their efforts have resulted in positive feedback from users and stakeholders. Moreover, the vendor impresses the client with their skills, flexibility, excellent project management, and effective communication.
The level of skill and quality of the developers is outstanding!
Emerline has been helping the client significantly improve their apps for 1.5 years. Their efforts have resulted in positive feedback from users and stakeholders. Moreover, the vendor impresses the client with their skills, flexibility, excellent project management, and effective communication.
Director, RedWrasse Ltd.
UK
Director, RedWrasse Ltd.
UK
Impressed with transparency, proactiveness, and customer-oriented processes
Emerline helped the client deploy the mobile app on the app store. Their team impressed the client with their transparency, proactiveness, and customer-oriented processes. They informed the client about any issues and addressed them swiftly, positively affecting the product quality and work speed.
Impressed with transparency, proactiveness, and customer-oriented processes
Emerline helped the client deploy the mobile app on the app store. Their team impressed the client with their transparency, proactiveness, and customer-oriented processes. They informed the client about any issues and addressed them swiftly, positively affecting the product quality and work speed.
CEO & Founder, Visible
Switzerland
CEO & Founder, Visible
Switzerland
My experience with Emerline has been great
The team was hired to design and develop the Echospectra mobile and web applications, as well as to integrate them with a variety of cloud services. A critical requirement was to rapidly develop the apps in an agile manner, quickly implementing important stakeholder and user feedback as it came along, and fixing any outstanding bugs. The team managed to accommodate this kind of agile, change-driven process successfully. Thanks to their rapid development approach, we've been able to build the initial app versions and then continuously iterate on them to refine our product offering and make sure it meets and exceeds customer expectations. I highly recommend them to anyone looking for a reliable partner who delivers on time and on budget.
My experience with Emerline has been great
The team was hired to design and develop the Echospectra mobile and web applications, as well as to integrate them with a variety of cloud services. A critical requirement was to rapidly develop the apps in an agile manner, quickly implementing important stakeholder and user feedback as it came along, and fixing any outstanding bugs. The team managed to accommodate this kind of agile, change-driven process successfully. Thanks to their rapid development approach, we've been able to build the initial app versions and then continuously iterate on them to refine our product offering and make sure it meets and exceeds customer expectations. I highly recommend them to anyone looking for a reliable partner who delivers on time and on budget.
CEO, Echospectra
USA
CEO, Echospectra
USA
They were very successful in listening to what we needed
They were very successful in listening to what we needed, making the appropriate suggestions, and pointing us in the right direction. They helped move our software from an awkward and crashy program to one that we depend on everyday. We couldn't do what we do without it.
They were very successful in listening to what we needed
They were very successful in listening to what we needed, making the appropriate suggestions, and pointing us in the right direction. They helped move our software from an awkward and crashy program to one that we depend on everyday. We couldn't do what we do without it.
Business Director, 3QC, Inc.
USA
Business Director, 3QC, Inc.
USA