1/ ⏳ The Serverless Achilles' Heel

Next.js API Routes timeout in 10-60s.
A long YouTube transcription takes 5 minutes.
Sync processing = 504 Timeout = User churn.
You need an async queue.

2/ 🔄 Architecture: HTTP as a Queue

We use Upstash QStash.
The API pushes a task to QStash and returns '202 Accepted' instantly.
QStash calls your Worker Webhook in the background with automatic retries and exponential backoff.

3/ 🛡️ The Secure Consumer

Your Worker is a public API Route. To prevent abuse, signature verification is a must.
We use verifySignature to ensure the request is actually from QStash.

4/ 🚦 Redis as Body Armor

Beyond queues, we use Redis for Rate Limiting.
Prevent malicious users from draining your LLM credits.
With Sliding Window limiters, we protect the API without sacrificing performance.