AI gateway vs AI firewall: what each one controls
The two terms get used interchangeably, and the difference matters most at the moment of a security review. An AI gateway decides where a request goes. An AI firewall decides whether it may go at all, and proves the decision afterwards.
What an AI gateway controls
A gateway is the single entry point in front of many model providers. Its job is reliable, cost-aware delivery.
- One API in front of many backends, with provider keys held centrally
- Routing policy: which model serves which traffic
- Resilience: retries on rate limits, failover to another provider
- Caching and request shaping to reduce spend
What an AI firewall adds
A firewall treats each request as a governed action with an identity and a policy outcome.
- Content inspection inbound and outbound: injection, personal data, toxicity, exfiltration
- Semantic policy: score intent against plain-language rules, not just keywords
- Identity: authenticated callers with roles and scoped access
- Decision records an auditor can read, without retaining content
Where the two overlap, and where the gap is
Most gateways have grown a thin policy layer, and most firewalls route traffic. The differences show up in edge behaviour.
- If guardrails are delegated to a hosted service, your prompts leave your network
- If policy is expressed per route rather than per identity, agent workloads slip through
- If the default on failure is pass-through, the control disappears exactly when you need it
Why one process matters
When inspection, policy and routing live in one process, the decision is made before the request moves. When they are separate services, each hop is a place where a failure, a timeout or a misconfiguration changes the outcome.
- One evaluation order, applied consistently to every caller
- No second network path for the prompt to travel
- One audit record per transaction, not fragments across systems
How to tell which one you have today
Ask three questions of any product you are evaluating.
- Can it refuse a request for policy reasons, not just route it?
- Does it know the identity behind the request, or only the key?
- Does it default to blocking or forwarding when inspection cannot run?
Common questions
Yes, and that is the design worth looking for. Routing, resilience and caching sit in front of inspection, policy and audit in a single process, so nothing is forwarded before policy is decided.
Not for prompt and response inspection. Keeping evaluation local removes a third party from your data path and removes the availability dependency that a hosted classifier introduces.
Text rules and masking are negligible. Semantic scoring is a model inference; gate-based designs cap how much of a large prompt is scored and fall back to the original when a gate cannot run, so the cost stays bounded.
Validate it yourself with our Technical Plan
A step-by-step guide to running your own proof of concept and a full head-to-head comparison, in your own environment, so you can decide on evidence rather than on a feature table.