I also just tried promoting the mock pull request to production, just to verify that this was not related to preview environment variables, but the issue still persists.

Hi,

Have you got chance to check with Neon support team? https://neon.tech/docs/introduction/support#support-tickets

No, since as I've tried to explain, I have litterally not touched anything, and now it doesn't work.

My preview and production is runnning 100% the same code, including the dependencies to Neon

Can you share the last working deployment and first broken deployment link?

This is the main branch which has been running for 55 days with no issues https://svelte-budget-planner-es1b20ima-frederiknorlyks-projects.vercel.app/.

This is the preview branch which is identical to the main branch and was deployed one day ago, but which has the errors: https://svelte-budget-planner-9cjcn2vxt-frederiknorlyks-projects.vercel.app/

Turns out my database had been automatically migrated from a vercel database to a Neon database without my knowledge, which explains the change in behaviour. The fact that this can break deployements is a bit worrying, and also the fact that I was not notified annoys me a bit.

I changed my dependencies from @vercel/postgres-kysely to use kysely-neon. This seems to work.

Hey Frederik! Thanks for your reply and I am glad to hear that you were able to identify the issue. We have not received any reports from existing SDK users who are already using @vercel/postgres about workflow disruptions. Although I am not sure 💯 confident about postgres-kysely package. However, You likely received an email directly from our Vercel Marketplace team on this communication as well:

Subject: No Action Required: Vercel Postgres transition to Neon-managed service on Vercel Marketplace

We’re making updates to improve your experience with Vercel Postgres. As part of this transition, your Vercel Postgres databases will now be managed by Neon in the Vercel Marketplace. This migration will happen automatically with no downtime and no action required on your part. Here’s what to expect:

What’s Staying the Same

• Pricing: Your pricing will remain the same, with no increase to the rates you are currently paying.
• Data collection: All data currently processed and disclosed between Vercel and Neon will stay the same. No new data will be collected or processed.
• No Downtime: Your service will continue without interruption.

What’s changing

• Billing ~~transition:~~ You will continue to be billed at the same rate, but you will receive a new invoice from Vercel Marketplace on behalf of Neon, separate from your standard Vercel invoice.
• Support: Your database will remain accessible through the Vercel Dashboard, with extended access available on Neon's platform. Neon will be responsible for providing direct support moving forward.
• Extended capabilities: You will now have full, integrated access to all of Neon’s latest features and updates.

If you have any questions or concerns regarding this migration, please contact our support team.

Thank you for trusting us as we continue to improve your experience!

The Vercel Team

• https://vercel.com/changelog/neon-now-available-on-vercel-marketplace
• https://neon.tech/docs/guides/vercel-postgres-transition-guide