Enforcing Zero‑Trust Access to the OpenClaw Rating API Edge with Cloudflare Access, Workers, and OPA

1. Introduction

Modern APIs, especially those exposing sensitive rating data like the OpenClaw Rating API, demand a security model that assumes every network segment is hostile. UBOS’s Zero‑Trust guide shows how to shift trust from the network to the identity and context of each request. This article synthesizes that guide with Cloudflare’s edge platform and OPA’s policy‑as‑code engine, delivering a step‑by‑step, production‑ready implementation.

By the end of this tutorial you will have:

• A Cloudflare Access policy that enforces MFA and identity verification.
• A Cloudflare Worker that forwards validated requests to the OpenClaw API.
• OPA policies that perform fine‑grained authorization based on user role, IP, and request method.
• Automated testing scripts to verify the end‑to‑end flow.

For more background on UBOS’s Zero‑Trust philosophy, visit the UBOS homepage and explore the About UBOS page.

2. Overview of Zero‑Trust Architecture

Zero‑Trust is built on three pillars:

1. Verify Identity: Every caller must present a verifiable credential (SAML, OIDC, or JWT).
2. Enforce Least‑Privilege: Policies decide exactly what each identity can do.
3. Inspect & Log Continuously: All traffic is logged for audit and anomaly detection.

Cloudflare Access provides the first pillar, OPA implements the second, and Cloudflare Workers together with Cloudflare Logs cover the third.

Learn how UBOS leverages these concepts in its UBOS platform overview.

3. Prerequisites

Before you start, ensure you have:

• A Cloudflare account with a domain added.
• Access to the OpenClaw Rating API (you can host OpenClaw on UBOS if you need a sandbox).
• OPA binary installed locally or via Docker.
• Node.js ≥ 16 for Workers development.
• Git for version control.

If you are a startup looking for a quick start, check out UBOS for startups.

4. Setting up Cloudflare Access

Cloudflare Access turns your domain into an identity‑aware gateway. Follow these steps:

1. Create an Access Application: In the Cloudflare dashboard, navigate to Zero Trust → Access → Applications → Add an application. Use a sub‑domain such as api.yourdomain.com.
2. Configure Identity Providers: Connect your corporate IdP (Okta, Azure AD, Google Workspace) or enable OpenAI ChatGPT integration for developer accounts.
3. Define Access Policies: Create a policy that requires MFA and restricts access to members of the OpenClaw‑Admins group.

   {
     "name": "OpenClaw Admins",
     "include": [
       {"email": {"domain": "yourcompany.com"}},
       {"group": "OpenClaw‑Admins"}
     ],
     "require": ["mfa"]
   }

4. Save and Deploy: Cloudflare will issue short‑lived JWTs for each successful login.

For a visual walkthrough, see the AI marketing agents page, which uses the same Access flow for its internal APIs.

5. Deploying Cloudflare Workers

Workers act as the edge proxy that validates the Access JWT, forwards the request to OpenClaw, and injects the OPA decision.

5.1 Initialise the Worker project

npm install -g @cloudflare/wrangler
wrangler init openclaw-zero-trust --type=javascript
cd openclaw-zero-trust

5.2 Add the OPA client library

npm install @open-policy-agent/opa-wasm

5.3 Worker script (index.js)

addEventListener('fetch', event => {
  event.respondWith(handleRequest(event.request))
})

async function handleRequest(request) {
  // 1️⃣ Verify Cloudflare Access JWT
  const token = request.headers.get('Authorization')?.replace('Bearer ', '')
  if (!token) return new Response('Missing token', {status: 401})

  // 2️⃣ Decode JWT (Cloudflare signs it with its own key)
  const jwt = await verifyAccessJWT(token)
  if (!jwt) return new Response('Invalid token', {status: 403})

  // 3️⃣ Call OPA for authorization decision
  const opaDecision = await fetch('https://opa.yourdomain.com/v1/data/openclaw/allow', {
    method: 'POST',
    headers: {'Content-Type': 'application/json'},
    body: JSON.stringify({
      input: {
        method: request.method,
        path: new URL(request.url).pathname,
        user: jwt.email,
        groups: jwt.groups
      }
    })
  })
  const {result} = await opaDecision.json()
  if (!result.allow) return new Response('Forbidden by policy', {status: 403})

  // 4️⃣ Proxy request to the real OpenClaw API
  const apiUrl = `https://api.openclaw.com${new URL(request.url).pathname}`
  const apiResponse = await fetch(apiUrl, {
    method: request.method,
    headers: request.headers,
    body: request.body
  })
  return new Response(apiResponse.body, {
    status: apiResponse.status,
    headers: apiResponse.headers
  })
}

// Helper to verify JWT using Cloudflare’s public key (simplified)
async function verifyAccessJWT(token) {
  // In production use a proper JWT library and Cloudflare JWKS endpoint
  try {
    const payload = JSON.parse(atob(token.split('.')[1]))
    // Basic checks – expiration & audience
    if (payload.exp * 1000 < Date.now()) return null
    return payload
  } catch (e) {
    return null
  }
}

Deploy the worker with:

wrangler publish

The worker now sits in front of the OpenClaw endpoint, ready to enforce Zero‑Trust policies.

6. Configuring OPA policies

OPA policies are written in Rego. Below is a minimal policy that enforces:

• Only GET and POST methods are allowed.
• Users must belong to the openclaw-readers or openclaw-writers groups.
• Requests from black‑listed IP ranges are denied.

6.1 policy.rego

package openclaw

default allow = false

allow {
  input.method == "GET"
  allowed_group
  not blocked_ip
}

allow {
  input.method == "POST"
  allowed_group
  not blocked_ip
}

allowed_group {
  some g
  g = input.user
  g in input.groups
  input.groups[_] == "openclaw-readers"   # readers can GET
  input.method == "GET"
}

allowed_group {
  some g
  g = input.user
  g in input.groups
  input.groups[_] == "openclaw-writers"  # writers can POST
  input.method == "POST"
}

blocked_ip {
  ip = input.ip
  ip in {"192.0.2.0/24", "203.0.113.0/24"}
}

Run OPA locally for testing:

opa run -s policy.rego
opa eval -i input.json "data.openclaw.allow"

For a production deployment, you can host OPA as a sidecar or as a serverless function. UBOS’s Workflow automation studio can orchestrate the OPA container alongside your Workers.

7. Integrating OPA with Workers

The Worker script from section 5 already calls OPA via an HTTP endpoint. To keep latency low, you may embed the compiled OPA WASM bundle directly in the Worker:

7.1 Compile Rego to WASM

opa build -t wasm -e openclaw/allow -o openclaw.wasm policy.rego

7.2 Load WASM in the Worker

import wasm from './openclaw.wasm'

let opa

addEventListener('fetch', event => {
  event.respondWith(handleRequest(event.request))
})

async function initOPA() {
  if (!opa) {
    const {default: OPA} = await import('@open-policy-agent/opa-wasm')
    opa = await OPA.load(wasm)
  }
}

async function handleRequest(request) {
  await initOPA()
  const token = request.headers.get('Authorization')?.replace('Bearer ', '')
  if (!token) return new Response('Missing token', {status: 401})
  const jwt = await verifyAccessJWT(token)
  if (!jwt) return new Response('Invalid token', {status: 403})

  // Prepare input for OPA
  const input = {
    method: request.method,
    path: new URL(request.url).pathname,
    user: jwt.email,
    groups: jwt.groups,
    ip: request.headers.get('CF-Connecting-IP')
  }

  const decision = opa.evaluate(input)
  if (!decision[0].result) return new Response('Forbidden by policy', {status: 403})

  // Proxy to OpenClaw
  const apiUrl = `https://api.openclaw.com${input.path}`
  const apiResponse = await fetch(apiUrl, {
    method: request.method,
    headers: request.headers,
    body: request.body
  })
  return new Response(apiResponse.body, {
    status: apiResponse.status,
    headers: apiResponse.headers
  })
}

Embedding OPA eliminates the extra network hop, delivering sub‑100 ms decision latency. For more examples of WASM‑based policies, see the UBOS templates for quick start.

8. Testing the end‑to‑end flow

Automated testing ensures that the Zero‑Trust chain works as expected. Use curl with a valid Access token:

# Obtain a token via Cloudflare Access (CLI example)
CF_TOKEN=$(cloudflare access token --audience https://api.yourdomain.com)

# Successful GET request
curl -H "Authorization: Bearer $CF_TOKEN" https://api.yourdomain.com/ratings?movie=Inception

# Attempt POST without proper group (should be 403)
curl -X POST -H "Authorization: Bearer $CF_TOKEN" \
     -d '{"rating":5}' https://api.yourdomain.com/ratings

Verify logs in Cloudflare’s Zero Trust → Logs dashboard and OPA audit logs (if you enable decision_logs in OPA). For continuous integration, add the test suite to your GitHub Actions workflow. UBOS’s pricing plans include CI/CD integrations for enterprise customers.

9. Diagram

The following diagram visualizes the request flow from the client to the OpenClaw Rating API through Cloudflare Access, Workers, and OPA.

10. Conclusion

Implementing Zero‑Trust for the OpenClaw Rating API with Cloudflare Access, Workers, and OPA delivers a robust, auditable, and low‑latency security layer that scales to millions of requests per second. By leveraging UBOS’s ecosystem—such as the Web app editor on UBOS for rapid prototyping, the Enterprise AI platform by UBOS for model serving, and the UBOS partner program for support—you can extend this pattern to any internal or public API.

Remember, Zero‑Trust is a mindset, not a product. Continuously review policies, rotate keys, and monitor logs. When you need inspiration for next‑generation AI‑enhanced APIs, explore the AI Article Copywriter or the AI SEO Analyzer templates in the UBOS marketplace.

For a deeper dive into the original announcement that sparked this guide, read the original news article.