Ruby framework authored by Nick Sutterer that provides higher-level architectural building blocks on top of (or alongside) Rails: operations, cells, form objects and more. Version 1.1 introduced operations to slim down Rails controllers, but exposed a hidden call stack where users had to know which methods (like check_policy!) to override. Version 2.0 replaced the process method with a step DSL inspired by Scott Wlaschin's Railway Oriented Programming: two tracks, a mutable context object, nesting for composition, and DSL options like replace, insert, before/after and delete to customize workflows without module hacks; the developer gem renders operations as diagrams automatically. Version 2.1 adopts BPMN conventions, adds activities (boxes, circles, arrows, throwing/catching events), workflows spanning an application, tracing, and suspend/resume events to model long-running processes — used at the German police for e.g. one-time-password login. Trailblazer 2.1 heavily invested in developer experience: its tracer visualizes nested execution, shows where exceptions occur across deeply nested steps and which item of a collection failed — saving Nick thousands of hours while redesigning Reform 3. Reform 3 is now built on Trailblazer activities, with parsing/validation/persistence modeled as step pipelines you can extend by inserting steps (e.g. upcase a name before validation). Trailblazer also underpins Tyrant, a Devise replacement shipping predefined auth workflows. Paid gems are planned in addition to the open-source core, driven by company demand.