Emerline’s clients - SAP
Emerline’s clients - FUCHS
Emerline’s clients - Espresa
Emerline’s clients - TrueLedger
Emerline’s clients - CPG Data
Emerline’s clients - Praxie
Emerline’s clients - Beacon Council
Emerline’s clients - Yarowa
Emerline’s clients - GoDog
Emerline’s clients - Fast Formulator
Emerline’s clients - 8 sports
Emerline’s clients - Driv
Emerline’s clients - Hello Ralphie
Emerline’s clients - SquareDash
Emerline’s clients - SAP
Emerline’s clients - FUCHS
Emerline’s clients - Espresa
Emerline’s clients - TrueLedger
Emerline’s clients - CPG Data
Emerline’s clients - Praxie
Emerline’s clients - Beacon Council
Emerline’s clients - Yarowa
Emerline’s clients - GoDog
Emerline’s clients - Fast Formulator
Emerline’s clients - 8 sports
Emerline’s clients - Driv
Emerline’s clients - Hello Ralphie
Emerline’s clients - SquareDash
Emerline’s clients - SAP
Emerline’s clients - FUCHS
Emerline’s clients - Espresa
Emerline’s clients - TrueLedger
Emerline’s clients - CPG Data
Emerline’s clients - Praxie
Emerline’s clients - Beacon Council
Emerline’s clients - Yarowa
Emerline’s clients - GoDog
Emerline’s clients - Fast Formulator
Emerline’s clients - 8 sports
Emerline’s clients - Driv
Emerline’s clients - Hello Ralphie
Emerline’s clients - SquareDash

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

Clutch rating 4.9 out of 5 - client reviews.

25 Reviews on Clutch

100+successfully launched financial products

800+Experienced full-time employees

Our offices
Florida, USA
Miami - Headquarters
Poland
Wrocław
Lithuania
Vilnius
Germany
Heidelberg
Map of Emerline’s global office locations: USA, UK, Germany, Poland, Lithuania, Georgia.

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.

Emerline's payment gateway integration services

Gateway API integration

Our experts seamlessly integrate payment gateway APIs into your applications, including integration with legacy systems, so you get resilient payment flows, swift confirmations, and consistent refund and chargeback handling to keep business moving.

Payment methods enablement

We enable diverse payment options, from cards to e-wallets and bank transfers, and more, so your customers always find their preferred payment method, helping you boost conversions and adapt to every market.

Checkout implementation

Our team delivers sleek checkout pages or embedded payment interfaces, giving your customers fast, intuitive payment experiences and driving higher completion rates on every device.

Recurring billing integration

For subscription services, we design billing workflows that reduce missed payments, automate renewals, and support more predictable revenue collection, so your subscriptions and invoicing run without interruptions.

Payment orchestration and routing

We deliver multi-gateway payment routing and intelligent orchestration, can improve authorization rates and help reduce fees, providing failover and more reliable processing.

Compliance-ready implementation

Security and compliance are foundational to every implementation. We guard your data with end-to-end encryption, help you meet PCI DSS standards, and build auditable, trusted payment workflows.

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.

Transform your business with expert payment integrations that sync your applications, billing, and finance, creating a unified, high-performing transaction ecosystem.

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 Integration Use Cases by Business Model

Different business models place different demands on payment infrastructure. We design integrations that support the specific transaction flows, compliance constraints, and operational requirements of your platform.

E-commerce checkout optimization

In E-commerce, the integration must prioritize both conversion and operational reliability. Checkout flows are designed to process payments quickly, handle declines gracefully, and maintain consistent synchronization between payment status and order fulfillment.

Typical capabilities include secure card tokenization, saved payment methods, one-click checkout, streamlined refund handling, including partial refunds, and fraud-detection mechanisms that minimize friction for legitimate customers.

E-commerce checkout optimization

Subscription billing and proration

Subscription businesses require payment infrastructure that supports recurring lifecycle events, including renewals, plan changes, and billing adjustments.

Typical functionality includes automated trial management, renewal billing, proration for upgrades or downgrades, failed-payment recovery workflows, invoice generation, and webhook-based synchronization of subscription and user lifecycle states.

Subscription billing and proration

Marketplace and split payouts

Marketplaces introduce complex financial flows where payments must be distributed between multiple parties.

Typical capabilities include seller onboarding workflows, automated split payments, scheduled payouts, balance management for platform accounts, reconciliation of platform fees and commissions, and role-based administration tools for marketplace operators.

Marketplace and split payouts

On-demand services

Service platforms such as delivery or mobility apps require flexible payment timing.

Common functionality includes authorization holds before service delivery, delayed or incremental capture after service completion, support for tips and add-ons, cancellation flows, partial refunds, and real-time payment status visibility for operations teams.

On-demand services

B2B invoicing and bank transfer flows

In B2B environments, payments are often tied to invoices and approval workflows rather than instant checkout.

Typical integrations support invoice payment links, bank transfer methods such as ACH or SEPA, where applicable, payment reconciliation and fees, and automated posting of transaction data to accounting and financial management systems.

B2B invoicing and bank transfer flows

International expansion

Global platforms require payment infrastructure that adapts to local market expectations and regulations.

Typical capabilities include multi-currency pricing, integration of regional payment methods, localized checkout experiences, authentication flows such as 3DS2 for regulatory compliance, and multi-gateway architectures that improve geographic coverage and reliability.

International expansion

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.

STEP 1

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.
STEP 2

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.
STEP 3

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.
STEP 4

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.
STEP 5

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

Stripe
PayPal
Adyen
Worldpay
Authorize.Net
Skrill
Shift4
Square
Telr
PayU

Subscription and billing platforms

Chargebee
2Checkout
BlueSnap

Accounting and finance systems

QuickBooks
Xero

Banking and Open Banking APIs

Plaid
Tink
Salt Edge

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

The company’s methodologies and delivery practices have been acknowledged by several technology partners and industry organizations. These recognitions indicate alignment with established technical standards and professional practices.
view all awards
Emerline awards
97 awards
Top Fintech Software Development Company 2026
Top Fintech Software Development Company 2026
Top Fintech Software Development Company 2026
Top Fintech Software Development Company 2026
Top Fintech App Development Companies 2026
Top Fintech App Development Companies 2026
Top Financial App Developers 2026
Top Financial App Developers 2026
Top Financial Services Company 2026
Top Financial Services Company 2026
Customer Choice 2025
Customer Choice 2025
Top Service Provider 2025
Top Service Provider 2025

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.

4.9

25 Reviews on Clutch

25 Reviews on Clutch

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!

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Tracy B. Neal, President/CEO, CPG Data
Tracy B. Neal

President/CEO, CPG Data

USA

case study

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.

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Michael Lynch, CEO, Praxie
Michael Lynch

CEO, Praxie

USA

case study

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.

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Felicity Johnson, Founder, Hello Ralphie
Felicity Johnson

Founder, Hello Ralphie

USA

case study

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.

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Alex Shubat, CEO, Espresa
Alex Shubat

CEO, Espresa

USA

case study

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.

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Dr. Andreas Schwarzer, VP Global IT, FUCHS Group
Dr. Andreas Schwarzer

VP Global IT, FUCHS Group

Germany

case study

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.

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Matt Fruge, Founder and CEO, SquareDash
Matt Fruge

Founder and CEO, SquareDash

USA

case study

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.

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Renny Joy, IT Director, DRiV
Renny Joy

IT Director

USA

case study

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!

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Rodrick Miller, President & CEO, Miami-Dade Beacon Council
Rodrick Miller

President & CEO, Miami-Dade Beacon Council

USA

case study

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.

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Christian Callender-Easby, Founder & CEO, Kontango
Christian Callender-Easby

Founder & CEO, Kontango

USA

case study

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.

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Dr. Yelena Yesha, Key Partner and Project Leader, FastFormulator
Dr. Yelena Yesha

FastFormulator Key Partner and Project Leader

USA

case study

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.

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Natalie Boll, CEO, Founder of Tribela GmbH
Natalie Boll

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.

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Robert Gill, Director, RedWrasse Ltd.
Robert Gill

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.

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Raphaël Briner, CEO & Founder, Visible
Raphaël Briner

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.

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Jesse Sprague, CEO, Echospectra
Jesse Sprague

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.

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Business Director, 3QC, Inc.
3QC

Business Director, 3QC, Inc.

USA

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.