Cloudflare Tunnel / Access Authentication

Authenticate HTTP requests to services protected by Cloudflare Access using Service Token headers.

When to Use

• Access internal services exposed via Cloudflare Tunnel
• Authenticate to Cloudflare Zero Trust protected applications
• Make API calls to services behind Cloudflare Access
• Bypass Cloudflare Access login page for automated requests

Prerequisites

export CF_ACCESS_CLIENT_ID=xxxxxxxxxxxxxxxxxxxxxxxxxxxxx.access
export CF_ACCESS_CLIENT_SECRET=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Create Service Token

1. Go to Cloudflare Zero Trust Dashboard
2. Navigate to Access → Service Auth → Service Tokens
3. Click Create Service Token
4. Name your token and click Generate token
5. Copy both Client ID and Client Secret (shown only once!)

Configure Access Policy

Ensure your Access Application allows service token authentication:

1. Go to Access → Applications → Select your app
2. Add a policy with Service Token as Include rule
3. Select your created token

Important: When using $VAR in a command that pipes to another command, wrap the command containing $VAR in bash -c '...'. Due to a Claude Code bug, environment variables are silently cleared when pipes are used directly.

Usage

Basic curl Request

Add two headers to authenticate through Cloudflare Access:

bash -c 'curl -s \
  -H "CF-Access-Client-Id: $CF_ACCESS_CLIENT_ID" \
  -H "CF-Access-Client-Secret: $CF_ACCESS_CLIENT_SECRET" \
  "https://your-protected-service.example.com/api/endpoint"'

With Additional Authentication

Many services require both Cloudflare Access AND their own authentication:

bash -c 'curl -s \
  -H "CF-Access-Client-Id: $CF_ACCESS_CLIENT_ID" \
  -H "CF-Access-Client-Secret: $CF_ACCESS_CLIENT_SECRET" \
  -H "Authorization: Bearer $API_TOKEN" \
  "https://your-protected-service.example.com/api/endpoint"'

With Basic Auth

bash -c 'curl -s \
  -H "CF-Access-Client-Id: $CF_ACCESS_CLIENT_ID" \
  -H "CF-Access-Client-Secret: $CF_ACCESS_CLIENT_SECRET" \
  -u "username:password" \
  "https://your-protected-service.example.com/api/endpoint"'

POST Request with JSON Body

Write to /tmp/request.json:

{
  "key": "value"
}

Then run:

bash -c 'curl -s -X POST \
  -H "CF-Access-Client-Id: $CF_ACCESS_CLIENT_ID" \
  -H "CF-Access-Client-Secret: $CF_ACCESS_CLIENT_SECRET" \
  -H "Content-Type: application/json" \
  -d @/tmp/request.json \
  "https://your-protected-service.example.com/api/endpoint"'

Download File

bash -c 'curl -s -o /tmp/output.file \
  -H "CF-Access-Client-Id: $CF_ACCESS_CLIENT_ID" \
  -H "CF-Access-Client-Secret: $CF_ACCESS_CLIENT_SECRET" \
  "https://your-protected-service.example.com/file"'

Skip SSL Verification (Self-signed certs)

Add -k flag for services with self-signed certificates:

bash -c 'curl -k -s \
  -H "CF-Access-Client-Id: $CF_ACCESS_CLIENT_ID" \
  -H "CF-Access-Client-Secret: $CF_ACCESS_CLIENT_SECRET" \
  "https://your-protected-service.example.com/api/endpoint"'

Required Headers

Common Errors

Tips

1. Header order doesn’t matter – CF headers can be anywhere in the request
2. Works with any HTTP method – GET, POST, PUT, DELETE, etc.
3. Combine with other auth – CF Access + Basic Auth, Bearer Token, etc.
4. Token rotation – Rotate secrets periodically in Zero Trust dashboard

API Reference

• Cloudflare Access: https://developers.cloudflare.com/cloudflare-one/identity/service-tokens/
• Zero Trust Dashboard: https://one.dash.cloudflare.com/