Ismael Celis

I was on the Dead Code podcast again, as well as a live talk at LRUG, talking about event sourcing and command-driven apps in Ruby

A bunch of (mostly) Ruby side-projects, and how I hope they build into a comprehensive stack

Video of a presentation on Ruby and Event Sourcing I gave at Wroclove.rb 2026.

November 2025 talk on durable messaging, event sourcing and Ruby

Web framework emphasis on sync web controllers vs async background jobs leads to incohesive workflows.

Video of a presentation on Ruby and Event Sourcing I gave at Baltic Ruby 2025.

Things I've said on Bluesky in August 2025.

In Object Oriented programming, identity and behaviour are often conflated. But it can be usefuk to think of them as different concepts.

Modeling your domain as timelines instead of object graphs

Notes from my Dead Code Podcast episode on Event Sourcing and Ruby.

Understanding the role of commands in Event Sourcing

The Decide, Evolve, React pattern in Ruby, explained step by step

Testing Railway-oriented pipelines in Ruby.

Implementing middleware in a Railway-oriented pipeline in Ruby.

Implementing domain-specific steps and extending a Railway-oriented pipelines in Ruby.

Handling user input, errors and metadata in a Railway-oriented pipeline in Ruby.

A simplified approach to building composable data pipelines in Ruby, with examples and use cases.

The Command Layer is the place where business logic happens, user input is handled and decisions are made. In this article I explore the role of the Command Layer in event-sourced systems

The Event Store interface is the canonical data store in event sourcing, and it’s in charge of persisting and retrieving events produced by your system.