Why API Governance Fails, and how to Shift It Left

This page expands on the ideas from our API Days session, “Why API Governance Fails — and How to Shift It Left.”

Whether you discovered this link from the conference handout or arrived here while exploring Jargon’s approach to Shift Left API governance, you’ll find the full slide deck and related insights below.

A practical walkthrough using a real domain, modeled and governed in Jargon.

Step 1: Start with the Conceptual Model

Before diving into implementation, start by modeling the world as your business sees it. Focus on the entities that actually matter — like ShoppingCart, Product, or Shipment — and define their relationships without thinking about databases or REST endpoints. This shift in mindset ensures that your design reflects real business understanding, not just system architecture.

Shared Definitions, Not Shared Guesswork Domains in Jargon can import other Domains. Every import in Jargon is explicit, immutable, and versioned. That means teams can rely on upstream models without being surprised — and without reinventing the same structure in every service.

Step 2: Capture Domain Intent

Good modeling isn't just about structure — it's about clarity of ownership. Assigning each resource to a domain (e.g. Marketing owns Products, Sales owns Carts) creates clear boundaries that reflect how your organization operates. Jargon visualizes this intent early, helping teams understand responsibilities and dependencies before anything goes live.

Incremental by Design: Jargon lets you map intent first, then realize domains gradually. Proposed domains help you plan — without needing full buy-in up front.

Step 3: Apply Design Rules as You Model

Jargon enforces naming, structural, and semantic rules live as you type — not just after the fact. This helps you catch missteps early and stay aligned with team expectations. Rules are visible, consistent, and actionable — no linter setup required. Teams can tune and evolve rules as expectations shift — they aren’t hard-coded constraints, but living design agreements

Friction: Design rules might feel restrictive at first. Jargon helps by keeping them visible and editable. Think of them as living agreements — not just governance enforcement.

Step 4: Iterate Collaboratively and Semantically

With Jargon Suggestions, team members can propose changes without overwriting the original model. Each suggestion tracks semantic diffs, making it easy to review intent, leave comments, and merge improvements with confidence. Suggestions let teams see diffs, comment, and collaborate — all without blocking the live model.

No More Bottlenecks: Suggestions in Jargon don’t block progress. You iterate visually and semantically — just like code — with no risk to the live model.

Step 5: Version with Confidence

Jargon automatically detects breaking changes and recommends semantic version updates. Teams don’t need to interpret raw diffs — they get human-readable summaries that explain what changed and why it matters.

💡 Tip: Shift Left means version control isn’t just for devs. Semantic model changes let your analysts, architects, and designers participate with the same rigor — before anything breaks.

Step 6: Detect Model Drift and Notify Consumers

Jargon warns you when upstream domains you rely on have changed — and whether the changes are breaking or safe. No more silent breakage or long email chains — drift is visible and actionable. Instead of blindly copying resource structures or hoping other teams don’t make changes, Jargon lets you import versioned, immutable domains — treating upstream data contracts as packages. When a new version is available, you'll be notified, shown what changed, and supported in adopting it safely.

Build for Federation: Every domain is versioned. Teams can consume, trace, and upgrade models independently — without stepping on each other.

Step 7: Model Lifecycle Behaviour

Define the valid states of a resource and its transitions — like ShoppingCart moving from Created to Purchased. These lifecycles directly inform APIs, events, and system behavior.

Step 8: See the Ripple Effect of Upstream Change

When a shared field or structure changes — like switching a product ID from UUID to string — Jargon traces that ripple across all consuming domains. You’ll know what breaks before it does.

Step 9: Realize the Plan and Visualize It

The Town Plan makes domain progress visible. Placeholder domains turn green when modeled and versioned, helping product and architecture teams align and prioritize.

Step 10: Model APIs Against the Domain, Not the Database

Rather than writing OpenAPI by hand, you model APIs around domain resources — and generate specs, payloads, and documentation automatically. They’re versioned, linked, and reproducible. Artifacts are generated on release. Webhooks let you plug them into your dev pipeline instantly.

Ready for CI/CDJargon generates artifacts on release — OpenAPI, JSON Schema, JSON-LD — and webhooks let you plug in your dev pipeline.

Step 11: Make Models Operable and Observable

Jargon gives every domain a living homepage — complete with versioned links, diffs, artefacts, and commentary. These are real systems of record, not just diagrams on a whiteboard. Not just drawings — living APIs, schema, and contracts.

Built with Jargon. Want to try it yourself?