- What traffic is visible to the policy.
- Where enforcement physically happens — inside a gateway proxy, a browser extension, an API engine, or a transparent MITM proxy devices route to via a PAC file.
- Which filters are available to narrow the scope further.
- How
Log,Mask, andBlocktranslate into a concrete action on the wire.
Gateway
LLM traffic through a TrustGate gateway. Routes decide whether it acts as an embedded AI Gateway or a pure security layer on top of a third-party gateway or backend.
Browser
A signed browser extension that enforces on web-based LLMs (ChatGPT, Claude, Gemini, Copilot, Mistral Le Chat). The surface for shadow AI and copy-paste exfiltration.
API
An API engine (Serverless or Dedicated) your backends call directly. For workloads that can’t be placed behind a proxy but can afford one extra HTTP round trip.
Endpoint
A transparent MITM proxy that managed devices route AI traffic to via an MDM-pushed PAC file. Zero software on the device; covers desktop apps, IDE plugins, and CLIs.
At a glance
| Surface | Traffic it sees | Runs in | Integration? | Filters |
|---|---|---|---|---|
| Gateway | LLM traffic sent through a TrustGate gateway | Gateway engine (Serverless or Dedicated); routes point at LLMs, third-party gateways, or custom backends | Gateway (per-engine API keys) | Gateways · Routes · Tags · Use Cases |
| Browser | Prompts typed or pasted into web-based LLMs | TrustGate browser extension on the user’s browser | Browsers | Applications |
| API | Whatever the caller sends to the Actions API | API engine (Serverless or Dedicated) exposing the Actions API | API (per-engine API keys) | Engines · Tags · Use Cases |
| Endpoint | AI traffic from managed devices (IDEs, desktop apps, CLIs) to covered AI providers | A transparent MITM proxy the device reaches via an MDM-pushed PAC file (no software on the device) | Endpoint | Endpoints · Applications · Tags |
Surfaces and actions
All four surfaces share the same detector catalog and the same policy language. Only the enforcement mechanics ofLog, Mask, and Block differ — which is why the per-surface pages spell out each verb explicitly.
| Action | Gateway | Browser | API | Endpoint |
|---|---|---|---|---|
Log | Event recorded; traffic unchanged. | Event recorded; UX unchanged. | Decision + evidence returned; caller proceeds. | Event recorded; traffic unchanged. |
Mask | Payload rewritten before upstream and on response. | Input field / paste / upload rewritten in place before submit. | Rewritten payload returned to the caller to use instead of the original. | Request body (and non-streaming response bodies) rewritten by the proxy before they reach the upstream or the client. |
Block | Upstream never called; client receives an error. | Submit cancelled in the browser; content never leaves the machine. | Decision = block returned; caller is expected to abort. | Request blocked with a 403 JSON error; non-streaming responses replaced. Streaming responses can only be alerted (already delivered to the client). |
Log, Mask, and Block on the Gateway and Browser surfaces are hard guarantees. On the Endpoint surface they are hard guarantees on requests and non-streaming responses; streaming responses can only be alerted. On the API surface enforcement is a contract the caller must honor.
Layering surfaces
Surfaces are not mutually exclusive. A mature deployment layers them so the same detection (for example PII) is blocked wherever a prompt can leave the perimeter:- Gateway for owned apps and agents — hard guarantee on your own traffic.
- Browser for shadow AI in web chat apps.
- Endpoint for desktop apps, IDE plugins, and CLIs.
- API for backend jobs that can’t be proxied, or as a second-line check on another surface.
Block PII on all four is cheap and consistent. The control plane aggregates decisions from every surface into a single log stream.
Decision guide
Use this table to pick a starting point; then add overlapping surfaces as your threat model grows.Related
- Policies — the
Where / When / Thenmodel that runs on every surface. - Security capabilities — the shared detector catalog.
- Architecture — how the four surfaces share a single control plane.