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Overview

Langfuse uses PostgreSQL for transactional data and only uses the public schema. To keep Langfuse separate from the app’s Payload data, use a dedicated database in the same Neon project. Create a second database in your Neon project (e.g. langfuse). Langfuse will use that database and its public schema.

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1. Create the Database

Neon Console (easiest)
  1. Open Neon Console and select your project.
  2. Go to Branches -> select your branch -> Databases.
  3. Click Create and name it langfuse.
SQL Editor 
CREATE DATABASE langfuse;
CLI 
neon databases create --name langfuse

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2. Connection String

Use the same host and credentials as your existing Neon URL, and only change the database name:
  • Current (app): postgresql://USER:PASSWORD@ep-XXX-pooler.REGION.aws.neon.tech/neondb?sslmode=require
  • Langfuse: postgresql://USER:PASSWORD@ep-XXX-pooler.REGION.aws.neon.tech/langfuse?sslmode=require

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3. Environment Variables

When self-hosting Langfuse, set:
  • DATABASE_URL — Connection string above (pooled URL is fine).
  • DIRECT_URL — Same URL or a direct (non-pooled) URL for migrations.

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4. Use from this Repo (.env.local)

This project keeps Langfuse URLs in .env.local:
  • LANGFUSE_DATABASE_URL — Pooled URL (use as DATABASE_URL in Langfuse)
  • LANGFUSE_DIRECT_URL — Direct/unpooled URL (use as DIRECT_URL for migrations)
DATABASE_URL=$LANGFUSE_DATABASE_URL
DIRECT_URL=$LANGFUSE_DIRECT_URL

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5. Optional: Script

pnpm tsx scripts/create-langfuse-database.ts

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Option 2: Same Database (neondb)

You can run Langfuse against your existing neondb database. Langfuse will use the public schema. Your app uses PAYLOAD_DB_SCHEMA=payloadcms, so tables won’t conflict.
  • Pros: One database, no new DB to create.
  • Cons: Langfuse and app share the same DB; backups and scaling are shared.

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Summary

ApproachWhere Langfuse LivesWhat You Do
New DB (recommended)New DB langfuse -> publicCreate DB in Neon, set DATABASE_URL with /langfuse.
Same DBExisting neondb -> publicSet Langfuse DATABASE_URL to your current Neon URL.