Everything in a ledger begins with a transaction, and balances are calculated with these transactions. Designing your ledger architecture thoughtfully is more than just best practice—it allows you sleep well at night.

A well-designed architecture gives you confidence: you know where funds move, you can trace every step, and you trust your system. It leads to cleaner implementations, fewer surprises during audits, and smoother scaling as your products grow in complexity.

This article breaks the process down into three practical steps for designing your ledger architecture:

1. Define what success looks like: Understand your business needs, transaction flows, and operational dependencies.
2. Discover the patterns: Identify recurring balance types and relationships across customers and products.
3. Design the hierarchy: Organize balances into ledger folders that support clarity, scalability, and traceability.

Define what success looks like

Start by deeply understanding your business logic and product flow. Ask foundational questions like:

1. What types of transactions must your ledger capture?
2. How does money move per transaction workflow?
3. Which products, teams, or operations rely on your ledger data (balances & transactions)?
4. How frequently do you need to reconcile balances, and at what granularity?
5. What are your reporting needs—internal, regulatory, customer-facing?
6. How should audit trails be structured for traceability and compliance?

Designing your ledger shouldn’t be a solo effort. It’s a cross-functional process that benefits from the input of every team it touches. When teams collaborate to define these requirements, the result isn’t just a more resilient ledger, it’s better alignment across the board.

Discover the patterns

As you define requirements, key actors and relationships start to show up. Look out for patterns like:

1. Does each customer consistently have the same set of balances?
2. Are there balances tied to partners (e.g., banks, payment processors) or internal functions (e.g., revenue, fees)?

For example, Acme Finance, a fintech app with transfers and cards products, would benefit from creating and tracking two balances per customer: a main balance for deposits & withdrawals and a card balance for card-related transactions (authorizations, holds and settlements).

Design the hierarchy

With your structure in place, organize your balances into ledger folders based on your requirements.

1. Group balances by product type, location, or function.
2. Consider operational and audit needs, e.g., how will you query or roll up balances.

For Acme Finance, their Blnk ledger architecture will consist of 3 ledger folders: Customer Main Ledger, Customer Cards Ledger, and the General Ledger.

1. Customer Main Ledger: Groups all main balances associated with customer deposits and transfers.
2. Customer Cards Ledger: Contains all card-related balances.
3. General Ledger: Serves as the default ledger for internal balances, such as fees or contra accounts, etc.

💡 Helpful tip

You don't need to create ledger folders per customer. You can link all balances owned by a customer to a single identity representing the customer with Blnk.

Conclusion

With your ledger architecture in place, you set a clear foundation for how your fintech product handles money and scales. This approach allows you to be able to manage thousands to millions of balances with clarity and complete control.  

To learn more about ledger architecture, read our developer guide.