Introducing PayGate

Developers don’t always want to modify their backend apps just to charge for premium API features.

Summary

PayGate is a powerful iRule for F5 BIG-IP that implements pay-to-access functionality entirely at the network edge, with zero backend changes required.

Why PayGate?

  • Instant monetization of API endpoints — no code changes, no redeploys
  • Flexible entitlement via tokens stored in BIG-IP’s memory
  • Edge-enforced security: protected webhook, token validation, TTL handling
  • Self-contained operation: no external dependencies like Redis or iRulesLX
  • Business-aligned: measure demand, treat price as signal, and unlock revenue in hours

Architectural overview

🧩 How It Works

1. Protected Token Injection

Stripe sends a checkout.session.completed webhook → your Python handler which extracts the entitlement_token and sends it securely to BIG-IP (/cache-token) with a shared secret.

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# iRule snippet
when HTTP_REQUEST {
  if { [HTTP::path] eq "/cache-token" && [HTTP::header "X-Webhook-Secret"] eq $static::shared_token_secret } {
    # save token into table
  }
}

2. Table-Based Caching

Tokens are stored in a BIG-IP table with a 1-hour TTL. No Redis or external caching — it’s all in-memory on BIG-IP.

3. Edge-Gated API Requests

When the API client requests /api/v1/hyperlocal?entitlement_token=..., the iRule:

  • Extracts the token
  • Looks it up in the table
  • If found → injects a header (X-Entitlement-Tier) and allows the request
  • If missing or expired → redirects to /pricing, where users can pay again

🛠️ Demo & Code

  • GitHub Repo: mikeoleary/paywall-irule-demo
  • Complete iRule with webhook gateway, token cache, and premium routing
  • Python Flask webhook handler to verify Stripe events
  • /token-status and /purge-token endpoints on BIG-IP for monitoring and token cleanup (can be added easily but are not part of this demo)

💡 Detailed traffic flow

💡 Business Benefits

Feature Benefit
Edge enforcement No backend modifications needed
Real-time monetization Start charging premium instantly
Demand measurement Paywall conversion = clear product-market fit
Rapid iteration Change pricing, features, or TTLs without app release
Cost-efficient No extra infrastructure, all on existing BIG-IP

✅ What’s Next

  • 📈 A/B pricing tests — change price or TTL to optimize conversion
  • 📊 Usage analytics — track token issuance and redemption trends
  • 📦 Expand features — tier-based access, usage quotas, premium burst credits
  • 🔒 Packaging — package as a blueprint or DevCentral article

🚀 Get Started

  • Clone the repo and load PayGate iRule onto your BIG-IP
  • Deploy the Flask webhook on your VM
  • Create a Stripe product with entitlement_token metadata
  • Route /cache-token, /token-status, and /purge-token to your BIG-IP
  • Test the flow: pricing → checkout → API access

With PayGate, you’ve turned your BIG-IP into a revenue-generating edge gateway, empowering API monetization in hours, not months. Let me know what you think!

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