Event sourcing is a way of storing data where you keep the full list of changes instead of just the current result. Every meaningful thing that happens is saved as an event, in order. The state you see at any moment is rebuilt by replaying those events from the start.
A bank account is the classic example. The bank does not just store your balance as one number. It stores every deposit and withdrawal, and your balance is simply the sum of all of them. If you ever dispute a figure, the whole history is right there to check. That same idea, never overwrite, only append, is the heart of event sourcing and it fits naturally with an event-driven architecture.
Because nothing is ever deleted or overwritten, you get a precise audit trail and the ability to ask what did this look like last Tuesday. You can even fix a past mistake by adding a correcting event rather than quietly editing the record, which keeps the story honest. It pairs well with patterns like the saga pattern for coordinating long-running processes across multiple services, and it sits comfortably inside a system built from microservices. The trade-off is more moving parts and more storage, so it is worth it mainly when history and auditability really matter.
At TopDevs we reach for event sourcing when a client needs a verifiable trail of every change, such as in finance, logistics or regulated workflows, and we keep it out of projects where a simple database would do the job with less overhead.
