I spent the first three months of 2024 rebuilding our transaction ledger from a batch-processing system into a real-time event stream. The project was not glamorous. It involved rewriting forty-seven stored procedures, migrating two years of financial data, and arguing with compliance officers about latency guarantees. But when we finished, something fundamental had changed: money moved at the speed of software.
The death of end-of-day processing
Traditional banks settle transactions in overnight batches. Your balance is a snapshot from the last run, not a live number. That architecture made sense when mainframes were expensive and networks were slow. Neither constraint exists anymore: every transaction can now resolve as an event in a live account stream.