Openfy: Exploring a Reusable Backend for Fintech Applications

Openfy started from an idea I had while thinking about how much infrastructure a new fintech product has to build before it can even begin solving its actual customer problem.

Authentication, accounts, transactions, payment flows, analytics, savings products, and credit logic are not necessarily the differentiating part of a fintech product, but they still require substantial backend work. I wanted to explore what a reusable backend for those common capabilities could look like. That became Openfy.

It was an open-source project rather than a commercial product. The goal was not to build a complete financial institution in a repository. It was to explore the backend architecture and implementation patterns that could provide a starting point for developers and fintech teams building financial applications.

The Idea

A lot of fintech products eventually need similar foundations. A user needs an account. The application needs authentication. Transactions need to be recorded. Users need to see transaction history. Financial activity needs to be analyzed. Money may need to be split between different recipients. A lending product may need some form of credit assessment. A savings product may need rules around contributions, targets, and rewards.

These problems are not identical across fintech products, but they share enough common ground that repeatedly rebuilding all of them from scratch felt inefficient. Openfy was an attempt to explore that common layer. I designed the project as a backend foundation that developers could build on, rather than a complete end-user fintech application.

Defining the Initial Scope

The project started with a relatively broad feature set. The initial concept included user account management, JWT authentication, transaction management, transaction history, analytics, payment splitting, dynamic credit scoring, savings and investment plans, gamification around savings, and financial data protection.

The intention was to create a backend that could support different types of financial products rather than designing the entire system around one particular user interface or business model. That distinction influenced the way I thought about the APIs. The backend needed to represent financial operations rather than simply mirror the screens of one application.

Starting With the Backend

Openfy was built with Node.js and Express.js, with PostgreSQL as the primary database. The project used a conventional backend structure with separate application concerns rather than putting the entire system into a single collection of route handlers. The repository included separate areas for models, migrations, controllers, and application configuration.

That gave me a straightforward foundation for experimenting with the financial functionality without introducing unnecessary infrastructure. The project was intentionally focused on the backend. The idea was that a frontend could consume the APIs while the underlying financial capabilities remained independent of the presentation layer.

User Accounts and Authentication

The first requirement for most financial applications is identity. Openfy therefore included user account management and JWT-based authentication. The authentication flow covered account creation, login, and email verification.

This provided the foundation for the rest of the system. A transaction cannot meaningfully belong to an anonymous request. A savings plan needs an owner. Credit information needs to be associated with an account. Payment splitting requires authenticated participants. Identity became the starting point from which the other financial capabilities could be built.

Transaction Management

Transactions were another fundamental part of the system. Financial applications need a reliable representation of financial activity rather than simply storing a current balance. Openfy explored this through transaction records and transaction history, aiming to provide a backend representation that could support downstream functionality such as analytics and financial workflows.

This was also an early opportunity to think through an important distinction: a financial application should preserve what happened, not only the result of what happened. A current balance tells you where an account is. Transaction history tells you how it got there. That distinction becomes increasingly important as financial products become more sophisticated.

Transaction Analytics

Once transactions exist as structured records, they become useful beyond the immediate transaction itself. Openfy included transaction analytics as part of the backend, with the purpose of making financial activity queryable and useful for applications built on top of it. This could support questions around transaction activity and user financial behaviour rather than forcing every consuming application to build its own aggregation logic from raw records. The broader idea was that financial infrastructure should expose useful primitives rather than simply expose database records.

Payment Splitting

Payment splitting was another capability I explored in the project. The idea was to allow a payment to be divided across multiple recipients or destinations rather than treating every transaction as a simple sender-to-single-recipient operation. This is useful in several types of financial products, including platforms where payments need to be distributed among multiple participants.

Implementing the capability as part of the backend also reinforced the original objective of the project. Payment distribution is a piece of financial infrastructure that can appear in many different products. It does not necessarily need to be reinvented every time.

Dynamic Credit Scoring

Openfy also explored dynamic credit scoring. Credit assessment is an interesting backend problem because it involves turning financial and behavioural information into a decision or score. The project included dynamic credit scoring as one of its intended financial capabilities.

The important part of the experiment was not attempting to create a universal credit-scoring system. It was exploring how a backend could provide a structured place for credit-related logic to exist independently from the rest of a fintech application's presentation layer. This also highlighted one of the challenges of reusable financial infrastructure: different products can have very different definitions of creditworthiness. A reusable backend therefore has to provide enough structure to support different strategies without assuming that every financial product evaluates users in exactly the same way.

Savings and Investment Workflows

The project also explored savings and investment functionality. The original concept included savings plans with gamification as well as investment-oriented workflows, an attempt to model financial behaviour beyond traditional transactions.

A transaction answers what financial activity occurred. A savings plan introduces another question: what financial goal is the user trying to achieve? That changes the backend model. A savings product may need to understand targets, contributions, progress, and rules around completing a plan. The project therefore explored financial workflows rather than limiting itself to transaction storage.

Designing for Reuse

The central architectural idea behind Openfy was reuse. The project was intended for developers and fintech startups that might otherwise have to build the same foundational capabilities independently. That meant resisting the temptation to make the backend entirely specific to one imaginary fintech product. Instead, I wanted the core concepts to be useful across different applications: authentication should be reusable, transaction management should be reusable, analytics should be reusable, payment splitting should be reusable, and financial workflows should be extensible.

That approach sounds simple, but it introduces an interesting design problem: how do you build infrastructure that is generic enough to reuse without becoming so generic that it becomes difficult to use? Openfy was an early exploration of that problem.

Security and Financial Data

Financial applications cannot treat security as an afterthought. I designed Openfy around authenticated access and protection of financial data, with encryption for data in transit and at rest included in the project's design goals. JWT authentication provided the identity mechanism for API access.

The broader intention was that applications using the backend should have a foundation that took basic financial data protection seriously rather than leaving those concerns entirely to the consuming application. This was particularly important because reusable infrastructure has a larger responsibility than a single application. If a foundational component is insecure, every application built on top of it inherits some of that risk.

Why Open Source?

I deliberately made the project open source. Part of the reason was practical. A reusable backend is more useful when other developers can inspect how it works, modify it, and build on it.

But there was also an engineering reason. Open source creates a useful constraint. You have to explain what the project is. You have to document how to run it. You have to make the repository understandable to somebody who did not write the code. You have to think about contribution and project structure. Openfy included a README, contribution guidelines, and a GPL-3.0 license. The project was therefore not intended to remain a private experiment on my machine. It was an attempt to turn the experiment into something other developers could inspect and potentially extend.

What I Learned From the Project

Openfy was one of the projects that shaped how I thought about reusable backend infrastructure. The most important lesson was that financial functionality is rarely as generic as it initially appears.

Authentication is relatively straightforward to generalize. Transactions are more complicated. Payment splitting introduces business-specific rules. Credit scoring becomes even more dependent on the product using it. Savings and investment workflows can vary substantially between applications. That means reusable infrastructure needs to establish sensible primitives without pretending that every fintech product works identically. This became an important architectural consideration for me later.

The Limits of the Experiment

Openfy was not intended to become a production financial infrastructure provider, and I would not describe it that way today. It was an exploration. The repository established the project structure, authentication foundation, database layer, and early financial functionality, while the broader feature set represented the direction I wanted the project to explore.

That distinction matters. There is a difference between designing a financial backend and operating financial infrastructure at production scale. Openfy was primarily about the former. It gave me a place to experiment with the architecture and think through how common fintech capabilities could be represented as backend services.

Why I Stopped Working on It

Eventually, another project became much more important. Monesize started taking shape, and my attention moved toward building an actual financial and operational platform. At that point, continuing to develop Openfy alongside Monesize did not make much sense.

There was also an interesting overlap between the two projects. The questions I had been exploring in Openfy were beginning to appear in a much more concrete form inside Monesize. Instead of building a generic financial backend for hypothetical fintech applications, I was now building financial infrastructure for a real product with actual business requirements. The focus naturally shifted, and I left Openfy as an open-source project rather than pushing it indefinitely toward completion.

What Openfy Became

Openfy ultimately became an experiment in reusable financial backend infrastructure. It was an opportunity to explore financial APIs, authentication, transaction management, payment distribution, analytics, credit scoring, savings workflows, and reusable backend architecture.

It also became an early step toward questions that would later become much more important in my work. How should financial data be represented? How should financial operations be exposed through APIs? Which parts of a financial application can actually be generalized? Where does reusable infrastructure stop and product-specific business logic begin? Those questions did not end with Openfy. They followed me into Monesize.

Conclusion

Openfy was never intended to be the final answer to building fintech software. It was an experiment in asking a simpler question: what would a reusable backend for common fintech capabilities look like?

I built the foundation, explored authentication, transactions, analytics, payment splitting, credit scoring, and savings workflows, and released the project as open source. Then Monesize became the more important direction, and I stopped developing it. That does not make the project unsuccessful. It served its purpose. Openfy gave me a place to explore financial backend architecture before I had the opportunity to apply those ideas to a much larger and more concrete system. It is now an archived project, but the engineering questions it raised continued into the systems I built afterward.