[NDCOslo2024] Designing for Change with Vertical Slice Architecture – Chris Sainty
In the ever-shifting sands of software demands, where agility trumps rigidity and evolution outpaces stasis, Chris Sainty, a distinguished software architect and Microsoft MVP, advocates for a paradigm that embraces flux: Vertical Slice Architecture (VSA). With a wealth of experience in .NET ecosystems, Chris dissects the frailties of conventional layered paradigms, illuminating how VSA fosters adaptability, accelerates onboarding, and scales with success. His exposition, laced with pragmatic examples, challenges developers to reimagine structures that prioritize features over foundations, ensuring applications remain responsive to the inexorable tide of transformation.
Chris commences by lauding the endurance of layered architectures—presentation atop business logic atop data—yet probes their perils in contemporary contexts. As customer whims whirl and scaling surges demand swift pivots, layers ossify into obstacles, encumbering change with cross-tier tangles. VSA, conversely, carves applications into self-contained verticals—end-to-end features encapsulating all concerns—streamlining modifications and magnifying modularity. This feature-centric ethos, Chris argues, aligns with modern mandates: rapid iterations, effortless extensions, and intuitive ingress for new contributors.
Deconstructing Layers: Pitfalls of Traditional Tiering
Layered designs, Chris elucidates, excel in abstraction but falter in flux. Modifications ripple across strata—tweaking data access mandates presentation perturbations—breeding brittle bonds. Scaling amplifies agony: monolithic services swell, onboarding overwhelms with navigational nightmares. Chris recounts teams ensnared in “god classes,” where logic leeches into controllers, defying single-responsibility tenets.
VSA liberates by slicing vertically: each feature owns its orchestration, from input validation to persistence, minimizing interdependencies. In ASP.NET Core, MediatR handlers embody this, encapsulating requests with validators, mappers, and repositories. Chris demonstrates: a “Create Order” vertical integrates all facets sans layer leaks, easing evolution as requirements refine.
Trade-offs temper triumph: VSA risks redundancy in shared utilities, yet Chris counters with judicious extraction—domain entities for rules, infrastructure abstractions for emails—preserving purity without proliferation. His verdict: layers for legacy, VSA for vitality.
Embracing Verticals: Accelerating Agility and Onboarding
VSA’s virtues shine in speed: altering a feature confines chaos to its silo, slashing cycle times. Chris illustrates with e-commerce: updating checkout logic spans one slice, not sprawling services. Onboarding accelerates—newcomers grasp endpoints holistically, sans layer labyrinths—fostering faster fluency.
Scaling surges seamlessly: verticals deploy independently, microservices materialize modularly. Chris cautions misconceptions: VSA isn’t anarchy—tests tether slices, conventions coerce cohesion. In .NET, minimal APIs map verticals directly, ditching controllers for clarity.
His horizon: VSA as mindset, marrying DDD’s domains with feature focus, empowering teams to thrive amid tumult.
Navigating Nuances: Sharing Savvy and Strategic Choices
Code sharing, a VSA specter, resolves via domains: encapsulate business invariants—aggregates, entities—reusable across verticals, insulating infrastructure. Chris debunks duplication dogmas: external concerns like databases or notifications warrant abstraction, not replication, ensuring efficiency without entanglement.
Strategic selection: VSA suits volatile domains; layers linger in stable spheres. Chris’s compass: assess change cadence—frequent flux favors verticals.
Forging Forward: Building for the Inevitable
Chris’s capstone: architectures architect for alteration. VSA, with its slice-centric simplicity, equips ensembles to navigate novelty, nurturing nimble, navigable codebases that celebrate change.