DNAi Systems Architect Certification

A workable enterprise AI architecture has five layers: data and retrieval, model access, orchestration, application surface, and governance. Keep them loosely coupled so a change in one does not force changes in the others. The data layer owns retrieval, embeddings, and access control. The model layer is a gateway, never a direct SDK call scattered through your codebase. Orchestration holds prompts, tool definitions, routing, and retries. The application surface is where people actually work, and governance cuts across all four with logging, evaluation, and policy. The common failure is collapsing these layers, for example embedding vendor API keys and prompt strings directly into a CRM plugin. Six months later the vendor changes pricing or a model is deprecated, and you are rewriting twelve integrations instead of one config. Draw the boundaries first, on paper, and name an owner for each layer. When you scope a project, the question is not 'which model' but 'which layer does this touch, and who maintains it after launch.' That ownership question protects the team from inheriting orphaned glue code nobody understands.

Never let application code call a model provider directly. Put a gateway in front: a single internal service that exposes a stable interface, routes to whichever model fits the request, and handles auth, rate limits, retries, caching, logging, and cost attribution in one place. This is the highest-leverage decision you make. With a gateway, swapping a summarization task from one provider to a cheaper one is a routing rule, not a code change across forty services. The gateway is also where you enforce policy: redact PII before it leaves your perimeter, block prompts that violate retention rules, and tag every call with the requesting team for chargeback. Keep the interface narrow and boring. Resist the urge to expose every provider-specific parameter, because that leaks vendor lock-in back into your apps. A good test: if you cannot switch your primary model vendor over a weekend by editing configuration, your gateway is leaking. Build it early, before you have ten integrations, because retrofitting a gateway after sprawl is the most expensive cleanup an architect ever signs up for.