"Database operation failed" error with Vercel KV in Next.js app

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Hello Vercel Community,

I’m encountering a persistent issue with my Next.js application using Vercel KV for user registration. Despite following the documentation and implementing several debugging steps, I’m still unable to resolve this problem.

Issue:
When attempting to register a new user, I receive a “Database operation failed” error. The client-side error message is:

Steps taken:

  1. Verified all required environment variables are set (KV_URL, KV_REST_API, KV_REST_API_TOKEN, KV_REST_API_READ_ONLY_TOKEN).
  2. Implemented detailed server-side logging in the registration API route.
  3. Created a debug endpoint to test Vercel KV connection.
  4. Checked Vercel logs for any error messages during registration attempts.

Relevant code:

Registration API route (app/api/auth/register/route.ts):

import { NextResponse } from "next/server"
import { hash } from "bcryptjs"
import { kv } from "@vercel/kv"

export async function POST(request: Request) {
  console.log("Registration route called")
  try {
    const body = await request.json()
    console.log("Request body:", JSON.stringify(body))

    const { name, company, email, password } = body

    if (!name || !company || !email || !password) {
      console.log("Missing required fields")
      return NextResponse.json({ message: "All fields are required" }, { status: 400 })
    }

    try {
      console.log("Checking if user already exists")
      const existingUser = await kv.get(`user:${email}`)
      console.log("Existing user check result:", existingUser)

      if (existingUser) {
        console.log("Email already exists")
        return NextResponse.json({ message: "Email already registered" }, { status: 400 })
      }

      console.log("Hashing password")
      const hashedPassword = await hash(password, 10)

      const newUser = {
        name,
        company,
        email,
        password: hashedPassword,
      }

      console.log("Attempting to save new user")
      await kv.set(`user:${email}`, JSON.stringify(newUser))

      console.log("User registered successfully:", JSON.stringify(newUser))
      return NextResponse.json({ message: "User registered successfully" }, { status: 201 })
    } catch (dbError) {
      console.error("Database operation error:", dbError)
      return NextResponse.json({ 
        message: "Database operation failed", 
        error: dbError.toString(),
        stack: dbError.stack
      }, { status: 500 })
    }
  } catch (error) {
    console.error("Unhandled registration error:", error)
    return NextResponse.json({ 
      message: "Internal server error", 
      error: error.toString(),
      stack: error.stack
    }, { status: 500 })
  }
}
2

Hi, Nikhil! Welcome to the Vercel Community :wave:

Could you share a minimal reproducible example with us?

I’d also like to share some marketplace options, in case it’s helpful → Vercel Marketplace

5

One thing that may be causing this is Vercel KV has been sunset, and existing stores were automatically migrated to Upstash Redis in December 2024. If you’re still using the @vercel/kv package, it may not be fully compatible with the migrated backend.

I’d recommend:

  • Switching from @vercel/kv to @upstash/redis (docs here)
  • Double-checking your environment variables in the Vercel dashboard — the connection strings may have changed after the migration
  • If the store isn’t working at all, you can create a fresh one through the Vercel Marketplace

Let me know if that helps!