Open Source Banking Software
Core banking is unforgiving: every balance must reconcile, every entry needs a matching counter-entry, and regulators expect to trace it all - which is why building on a proprietary core puts your whole institution on top of a black box you can't audit. The open source ledgers and core-banking platforms here give you a double-entry foundation you can read, verify, and extend, rather than licensing the most critical layer of a fintech product from a vendor that owns it.

TigerBeetle
Financial transactions database with built-in debit and credit accounting, built for OLTP safety and speed

Apache Fineract
Open-source core banking platform for lending, savings, and other financial services

Open Bank Project API
Open source banking API platform for Open Banking, XS2A, PSD2, and Open Finance

Formance Ledger
Programmable double-entry ledger for money-moving applications, with atomic multi-posting transactions

Mifos X Web App
Angular-based web UI for the Mifos X platform with Apache Fineract as the backend