> ## Documentation Index
> Fetch the complete documentation index at: https://docs.neuraltrust.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Fastly Compute

> TrustGuard from a Fastly Compute service.

1. `npm create @fastly/compute` — handler in `src/index.js`.
2. Backends: `trustguard` (evaluate host), `origin` (app).
3. Key in a Fastly Secret Store.
4. `fastly compute publish` — Next-Gen WAF still runs first.

```js theme={null}
addEventListener("fetch", (event) => event.respondWith(handler(event)));

async function handler(event) {
  const req = event.request;

  if (req.method === "POST") {
    const text = await req.clone().text();
    const result = await fetch("{TRUSTGUARD_URL}/v1/evaluate", {
      method: "POST",
      backend: "trustguard",
      headers: {
        Authorization: "Bearer <collector-api-key>",
        "Content-Type": "application/json",
      },
      body: JSON.stringify({
        protocol: "llm",
        direction: "input",
        payload: { input: text },
        consumer_id: req.headers.get("x-user-id") ?? "",
        session_id: req.headers.get("x-session-id") ?? "",
      }),
    }).then((r) => r.json());

    if (result.status === "block") {
      return new Response("Blocked by TrustGuard", { status: 403 });
    }
    if (result.status === "transform" && result.transformed_payload) {
      return fetch(
        new Request(req, { body: JSON.stringify(result.transformed_payload) }),
        { backend: "origin" },
      );
    }
  }

  return fetch(req, { backend: "origin" });
}
```