goes

Appearance

Introduction ​

goes is an event-sourcing framework for Go. It provides the building blocks for modeling your domain with aggregates, persisting state as events, building read models with projections, and coordinating workflows across aggregates.

What is Event Sourcing? ​

In a traditional application, you store the current state of your entities in a database. When something changes, you overwrite the old state with the new state.

With event sourcing, instead of storing current state, you store the sequence of events that led to the current state. To get the current state, you replay the events from the beginning.

Traditional:  UPDATE accounts SET balance = 900 WHERE id = '...'

Event Sourced: INSERT event (name: 'account.debited', data: {amount: 100})
               → Current state is derived by replaying all events

This gives you a complete audit trail, the ability to rebuild state at any point in time, and natural integration points for other systems through event subscriptions.

What is DDD? ​

Domain-Driven Design (DDD) is an approach to software development that focuses on modeling your code around business concepts. Key patterns used in goes:

  • Aggregates — Consistency boundaries that protect business rules. They encapsulate state and validate changes before accepting them.
  • Events — Facts about what happened. Past-tense, immutable records of state changes.
  • Commands — Requests to do something. They express intent and are validated by aggregates before producing events.
  • Projections — Read-optimized views derived from events. Tailored for specific query needs, updated reactively as events flow through the system.

Why goes? ​

  • Generic where it matters — Typed events, commands, and repositories reduce boilerplate and catch mistakes at compile time.
  • Backend-agnostic — Swap between MongoDB, PostgreSQL, NATS, or in-memory backends without changing application code.
  • Production-ready — Built-in support for snapshots, optimistic concurrency, and continuous projections.
  • Minimal boilerplate — Define your aggregate, register event handlers, and the framework handles versioning, persistence, and replay.

Next Steps ​