Best practices for integrating WDK into existing Express app on GCP (non-Vercel deployment)

[technopahadi]

Context

I have an existing Express application running on GCP that I cannot migrate to Vercel. I'm interested in using WDK for durable workflows (with tight ai sdk integration) but I'm running into some architectural questions about the best integration path.

Current Setup

• Express app with significant business logic in src/
• Self-hosted on GCP Cloud Run
• PostgreSQL database available (primary data store)
• Redis available (for caching)
• GCP pubsub available (for queueing)

Challenges I've Identified

1. Nitro as build tool: The Express getting-started guide requires Nitro to compile "use workflow" and "use step" directives. My existing Express app has its own build pipeline and a lot of dependencies in src/ that workflows would need to reference. Concerned about bundling issues with native modules, database clients, etc.
2. Postgres World: Docs indicate it's a reference implementation not meant for production. Is there a recommended self-hosted production backend?
3. Vercel World from non-Vercel infrastructure: Is it possible/supported to use @workflow/world-vercel as the backend while the Express app itself runs on GCP? This would give me the managed infrastructure without migrating my app.

Questions

1. What's the recommended architecture for integrating WDK into an existing Express app that cannot be deployed to Vercel?
2. Are there plans to make Postgres World (or another self-hosted backend) production-ready?
3. Are there plans on making a GCP World?

Thanks for any guidance!