Finding a payment gateway development company is different from picking a processor like Stripe or Adyen. A development partner builds the actual software that moves money. They handle security, compliance, and connections to banks.

Not every software firm can do this work properly. Payment systems require PCI DSS knowledge, experience with acquirer integrations, and an understanding of settlement logic. The companies listed below have delivered production payment systems for real clients.

This list focuses on firms with verified payment gateway development expertise. Each entry includes what they actually build and who they have built it for.

1. ScienceSoft

ScienceSoft has operated since 1989, with 20+ years specifically in payment software and 22+ years in cybersecurity. The company is headquartered in the US with a presence in the EU.

Their payment gateway development methodology follows a structured seven-step process. ScienceSoft builds both custom gateways and integrations with existing processors. The firm serves ecommerce companies, fintech startups, and enterprise organizations across 30+ industries.

ScienceSoft breaks payment gateway integration into six stages. Scope definition takes one to three weeks. Project planning runs another one to two weeks. Design takes two to five weeks. Tech stack selection runs for two to three weeks. Implementation and testing take two to eight weeks. A custom gateway built more than doubles that timeline compared to standard integration.

Here is what a payment gateway integration project at ScienceSoft looks like.

A project manager sets the timeline and budget. A business analyst writes down what the system needs to do. A solution architect decides how everything connects. Developers build the code. A DevOps engineer watches for security problems and keeps the system running after launch. A QA engineer tests everything before customers use it.

Each project gets all seven roles assigned from the start.

ScienceSoft started doing security work in 2003. That means twenty-two years of looking for holes before criminals find them. The team includes people who passed the Certified Ethical Hacker exam. Clients get help meeting PCI DSS, GDPR, and SOC 2 rules from dedicated compliance staff.

Two certificates matter here. ISO 9001 says ScienceSoft follows consistent quality processes. ISO 27001 says they protect client data the right way. Both are independently audited every year.

Services: Integration consulting, custom gateway builds, merchant onboarding tools, transaction platforms

Compliance: PCI DSS, ISO 9001, ISO 27001

2. SPD Technology

SPD Technology builds custom payment gateways with PCI DSS and GDPR compliance built into the foundation. The company handles multi-currency processing and connections to processors, including Adyen and Stripe. Founded in 2006, the firm brings 18+ years of fintech engineering experience and operates as a product engineering partner rather than an outsourcing vendor.

Their payment work spans the UK, US, and EU markets. Core expertise includes fintech software development, payment platforms, and billing systems. The firm holds certified Adyen Implementation Partner status and serves fintech scale-ups alongside digital payment companies.

SPD Technology built full-cycle payment processing software for Poynt, now part of HP Commerce. That platform runs 140 million transactions each month. The company also delivered an aggregated merchant portal for BlackHawk Network that onboarded 8,000 US businesses in two years, reducing setup time by 7x. 

For a LegalTech platform with 20 million users, SPD Technology handled simultaneous payment integrations across multiple geographies with transaction transparency built into the system.

The company approaches compliance as an architectural foundation. Tokenization and network segmentation reduce PCI DSS scope from the start rather than as an afterthought.

Core services: Payment gateway software development, payment processing engines, security systems, PSP abstraction layers, merchant onboarding workflows

Compliance coverage: PCI DSS 3.2 compliant data storage, ISO/IEC 27001/27002:2005 standards, GDPR, PSD2, KYC, SOC 2 Type II ready

3. Andersen Lab

Andersen Lab launched in 2007 and operates from offices in the US, UK, and Europe. The firm employs more than 3,500 people globally.

One client was a Baltic FinTech company with an EU eMoney license, employing 300 people across 15 cities worldwide. Andersen built a payment gateway that serves as the payment processing tool for eShops. Merchants accept payments across different countries and currencies using cards, eBanking tools, and local payment methods.

The solution now serves over 700,000 clients across more than 20 countries. Users have performed over six million transfers across 20 different currencies. The project also included an LSTM neural network for detecting abnormal transaction behavior, trained via transaction logs to spot deviations from normal client patterns.

The firm operates with Scrum methodology and has launched mobile and watchOS applications as part of their payment ecosystem delivery.

Key services: Payment gateway development, fintech software, SWIFT/SEPA integration, custom API development

Compliance: PCI DSS, KYC, AML, GDPR, Fraud Prevention

4. Intellias

Intellias has delivered payment and banking software since its founding in 2002. The company has built systems for tier-1 European banks.

Intellias built a payment processing architecture for a European bank. The system stays online 24 hours a day, seven days a week. It fails only 0.259% of the time, which means 99.741% resistance to failure.

During an eight-hour peak window, that same system moves three million transactions. It serves nearly 30,000 business clients and five million people using mobile banking. The engineers picked Apache Flink for processing streaming data with very low delay. Kubernetes runs the whole setup in containers.

For an iGaming operator, Intellias rebuilt an outdated payment system from the ground up. The old code was no longer supported. The new platform works with Visa and Mastercard. Customers can deposit and withdraw money through a clean interface.

The firm modernizes old banking platforms into cloud-native systems. They also build white-label customer platforms that let companies launch branded payment products faster.

What they offer: Payment platforms, core banking modernization, white-label customer platforms, API-first open banking tools

Compliance focus: PSD2, PSD3, ISO 20022

5. Geniusee

Geniusee started in 2017. The company has its main office in the UK and serves EU markets. More than 250 people work there. They have finished over 180 client projects and hold a 5.0 customer rating.

The firm builds custom payment gateways that meet PCI DSS standards. Their systems connect to multiple payment providers and include fraud detection. Geniusee holds AWS Certified Partner status. They follow ISO-certified processes for quality and security.

Geniusee connects payment systems to banks through APIs. They handle transaction routing and settlement processing. The company also builds BNPL platforms from scratch. A basic version takes three to five months and costs $70,000 to $120,000. Full-featured systems need six to nine months or more. Enterprise platforms go above $250,000.

The company builds payment apps for web browsers, iPhones, and Android phones. The same features work across all three.

One of their projects involved migrating a shipping marketplace from Digital Ocean to AWS. The client needed better scalability. Geniusee set up CI/CD pipelines for smooth deployment and integrated Stripe and Venmo for payments.

Another client needed a white-label lending platform. Geniusee delivered a fully functional MVP within five months. The platform digitized manual lending workflows and added automated risk assessment.

What they offer: Custom gateway engineering, BNPL platforms, payment API connections, multi-provider routing

Compliance areas: PCI DSS, KYC, AML, ISO-certified processes

Final Thoughts

Choosing a payment gateway development company comes down to three factors. First, does the firm have verifiable payment project experience? Second, do they understand PCI DSS compliance from day one? Third, can they handle the specific processors and geographies needed?

The companies listed above have all delivered production payment systems. SPD Technology brings 18+ years of fintech engineering with verified enterprise scale. ScienceSoft offers structured integration methodology and in-house compliance expertise. Andersen Lab has delivered cross-border payment gateways for regulated EU institutions.

Intellias provides banking-grade payment platforms with high-volume transaction processing. Geniusee delivers cloud-native payment solutions and BNPL capabilities. Intellectsoft specializes in payment software and digital wallets. EPAM offers global payments transformation at enterprise scale. Eleks focuses on secure fintech products with fraud management.

A company handling less than $50 million in yearly transactions usually does better with off-the-shelf processors. Once volume passes that mark, custom payment infrastructure deserves a serious look. The right partner determines whether a gateway goes live on schedule or gets stuck in compliance checks.