Engineering a certified, production-ready FedNow platform for instant payments and future Payments-as-a-Service growth

Real-time payments are redefining how quickly customers expect businesses to move money. For a leading US fintech serving millions of customers through embedded financial services, faster access to funds was becoming central to delivering a more responsive customer experience and supporting the next stage of its payments strategy.

The fintech wanted to enable instant, cost-optimized money movement across use cases including merchant disbursements, invoice payments, bill payments, same-day payroll and loan-related payouts. FedNow, the Federal Reserve’s continuously available instant payment service, provided a path to reduce reliance on slower or more expensive payment rails while creating a platform for future Payments-as-a-Service capabilities.

Persistent partnered with the organization to design, build and operationalize a greenfield FedNow payments processing engine. The result was a certified, production-deployed FedNow Send platform built to support immediate payment needs while providing an extensible foundation for additional personas, workflows and payment services.

Moving from payment capability to always-on payment confidence

Connecting to an instant payment rail is only one part of the transformation. Every transaction must also meet stringent requirements for message accuracy, security, resilience and traceability.

FedNow payments settle within seconds and cannot be recalled, reversed or charged back. Unlike a traditional batch-based environment, there is no overnight processing window in which teams can identify and correct an error. The platform therefore had to operate reliably around the clock while complying with ISO 20022 messaging requirements, integrating with sponsor banks and partner systems and meeting Federal Reserve certification expectations.

The fintech needed more than a point integration. It required a production-ready payments engine that could align with its preferred cloud-native technology stack, conform to internal architecture principles and expand into new payment use cases without requiring future replatforming.

The initial scope centered on FedNow Send persona workflows. However, the architecture also needed to accommodate future capabilities such as Receive Credit Transfer, Request for Payment, payment orchestration, Third-Party Service Provider expansion and Payments-as-a-Service.

Designing a platform for a rail that never closes

Persistent approached the initiative as a strategic engineering program rather than a standalone integration. Payments specialists, product engineers and cloud-native technology teams worked closely with the fintech’s business stakeholders, product owners, architects, security teams and external ecosystem participants.

Full-week workshops, remote working sessions and recurring design reviews helped the teams clarify requirements, make architecture decisions and maintain delivery momentum. Persistent also identified specialized capabilities early and onboarded skilled team members, including payments business analyst and IBM MQ administrator, to reduce execution risk around critical integration activities.

The solution combined microservices and event-driven design patterns with Java Spring Boot services deployed on Kubernetes. Relational persistence, event streaming, messaging integration, CI/CD automation and centralized monitoring supported delivery across environments. IBM MQ provided messaging connectivity to FedNow while automated pipelines and engineered test coverage enabled repeatable development and deployment.

An API-first architecture and domain-aligned microservices enabled the FedNow module to integrate with the fintech’s existing money movement services and partner ecosystem. Secure communication, observability, auditability and structured exception handling were embedded into the platform design to support operational control and future extensibility.

Accelerating delivery through AI-assisted engineering

Persistent incorporated AI-assisted engineering across the software development lifecycle to increase delivery speed while maintaining the controls required for a regulated payment platform.

Tools including Claude and Cursor supported requirements elaboration, design exploration, code generation, test-case creation, refactoring, documentation and review preparation. Rather than limiting AI to code completion, the team used it as an engineering co-pilot across the software development lifecycle, supporting activities such as design exploration, code generation, testing, documentation and code reviews.

Controlled AI use contributed to an observed increase of approximately 30% in sprint velocity and an approximately 50% reduction in pull request shipping time.

The governance boundary remained explicit. Domain specialists and engineering leads retained responsibility for validating outputs, reviewing security considerations and ensuring production-grade quality. AI accelerated the engineering process but did not replace accountable decision-making. This distinction was particularly important for an irrevocable payment rail where every released message had to be accurate, secure and operationally sound.

Embedding compliance and quality into every release

For an always-on payment platform, quality engineering could not be treated as a final delivery phase. Persistent embedded it throughout the implementation lifecycle.

Structured design documentation, automated testing, component testing, message validation, integration testing, security reviews and operational monitoring created multiple layers of assurance. FedNow messages were validated against ISO 20022 expectations while simulation layers and lower-environment testing supported end-to-end validation before ecosystem-level integration.

Security and operational readiness reviews were completed before production activation. This approach helped build confidence that the platform could support real-world payment processing while meeting the fintech’s requirements for resilience, traceability and control.

Turning a greenfield build into a production payments platform

The engagement moved the fintech from having no FedNow capability to operating a certified, production-deployed FedNow Send platform.

Persistent built a greenfield payments engine supporting more than 30 payment workflows and over 15 ISO 20022 message types. FedNow certification was completed with the Federal Reserve in February 2026 alongside integration with the relevant banking and network participants.

Production validation began with a microdeposit-based use case, confirming the full transaction path from origination to settlement on live infrastructure. The platform has since processed more than 75,000 FedNow credit transfers.

Beyond achieving go-live, the program established an internally controlled processing model that allows the fintech to direct eligible real-time payment volume toward a more cost-optimized rail. Its modular architecture also provides a path to add Receive Credit Transfer, Request for Payment, payment orchestration and Payments-as-a-Service capabilities without replatforming the core engine.

The client recognized the FedNow program as a “game-changing” strategic milestone and highlighted the team’s technical knowledge, execution discipline, governance and sustained momentum across a complex payment ecosystem.

Business outcomes at a glance

• Certified and production deployed: The fintech progressed from no FedNow capability to a certified FedNow Send platform operating on live infrastructure.
• 75,000+ credit transfers processed: The production platform has processed more than 75,000 FedNow credit transfers following validation of the initial microdeposit use case.
• 30+ payment workflows enabled: The greenfield engine supports more than 30 payment workflows across over 15 ISO 20022 message types.
• Approximately 30% higher sprint velocity: Governed AI-assisted engineering increased the observed sprint velocity while preserving human-led validation and quality controls.
• Approximately 50% faster pull request shipping: The AI-assisted development approach reduced the observed time required to move pull requests through the delivery process.
• A platform for future payment services: The architecture can support additional FedNow personas, Request for Payment, orchestration and Payments-as-a-Service without replatforming the foundational engine.

Creating a foundation for the next generation of digital payments

The implementation gives the fintech more than access to a new payment rail. It establishes a modern payments processing backbone built for speed, compliance, resilience and extensibility.

Future phases can expand automation coverage, strengthen performance and service-level benchmarking, address technical debt introduced during certification and enhance nonfunctional design. The platform can also evolve into Receive Credit Transfer and Request for Payment scenarios as the fintech broadens its instant payments portfolio.

The program also reinforced several principles for always-on payments transformation. Availability, throughput and failover expectations need to be defined early because they shape the architecture. Alignment with existing enterprise platforms reduces downstream rework while comprehensive documentation improves auditability and maintainability. Automation becomes increasingly important as payment workflows move across environments. AI-led engineering can accelerate delivery but creates sustainable value only when paired with security guardrails, domain-led validation and accountable human oversight.

As instant payments become fundamental to financial services, organizations need more than connectivity. They need platforms that bring together operational resilience, regulatory readiness and the flexibility to support evolving customer needs. For this fintech, the FedNow implementation created that foundation and opened a path toward a broader portfolio of platform-based payment services.

Ready to modernize your real-time payments ecosystem? Talk to Persistent about building secure, scalable and extensible instant payment platforms.