High-Performance POS Transaction Processing System


Our customer, an innovative fintech startup, envisioned a system that would connect millions of point of sale terminals in retail and other establishments across the country to a single cloud-based backend, which would allow to track, record, store, analyze, and visualize cash transaction data so it can be used for a variety of purposes (fiscal, retail analytics, digital marketing, etc.).

First Line’s Solution

First Line’s engineers architected and developed an extremely high-performance system that enables over 2.5 million POS terminals to stream cash transactions data in real time to the cloud backend. After capturing the transaction, the system and returns a unique code to the POS terminal in a fraction of a second, which is printed on the customer receipt. Any customer can later go online, find their individual transaction and verify that it was properly recorded; this also enables other services, e.g. taking part in a lottery.

The heart of the system is a very robust, high load, high performance database. The system is capable of processing over 15,000 transactions per second, with peak throughput of over 70,000 transactions per second. That’s over 1.5 billion transactions per day. The operational data capture is powered by Redis, and the persistence database is implemented using PostgreSQL. The persistence storage is also highly secure and uses hashes to prevent any subsequent changes to the captured data.


First line has developed a system that achieves enormous performance on an open source software stack, and using relatively inexpensive hardware, which helps control TCO as the system is being scaled.

The service-oriented architecture of the system provides for a way to continuously and seamlessly add new services in the future. In addition to high performance and success with big data operations, the system will also offer a set of services to retailers around big data analytics and data visualization, such as financial analysis, accounting and bookkeeping, demand analytics, warehouse services, and many and others. First Line is performing the business analysis, as well as UX and UI design for all services.


Linux Debian/Ubuntu, C++, Boost, Google protobuf, OpenSSL, Java, Spring, JDBC, Crypto Pro JCP/JTLS, Jetty, REST, JSON, PHP, JavaScript, Apache Thrift, Redis, PostgreSQL, Zabbix, nginx

Project statistics

Team size: 15

Total effort: 225 person-months

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