Great question. In Prefect 3.x, the server uses SQLite by default, but you can point it to your Postgres RDS by setting the server database settings. Here’s the quickest path: Summary of steps - Install the Postgres driver - Point Prefect Server at your RDS URL - Restart the server (it will run migrations automatically) 1) Install the async Postgres driver in the same environment running your server

pip install asyncpg

2) Set the database connection for Prefect Server Option A — single URL (recommended)

export PREFECT_SERVER_DATABASE_CONNECTION_URL="postgresql+asyncpg://<USER>:<PASSWORD>@<RDS_HOST>:5432/<DB_NAME>"
prefect server start

Option B — individual fields (equivalent to the URL)

prefect config set \
PREFECT_SERVER_DATABASE_DRIVER=postgresql+asyncpg \
PREFECT_SERVER_DATABASE_HOST=<RDS_HOST> \
PREFECT_SERVER_DATABASE_PORT=5432 \
PREFECT_SERVER_DATABASE_USER=<USER> \
PREFECT_SERVER_DATABASE_PASSWORD=<PASSWORD> \
PREFECT_SERVER_DATABASE_NAME=<DB_NAME>
prefect server start

Notes - Migrations: Prefect runs DB migrations on startup by default (

migrate_on_start=True

), so you don’t need a separate migration command. - Security/Network: Ensure your EC2 instance can reach your RDS (VPC/security groups). If your RDS enforces TLS, you may need to configure TLS settings; Prefect exposes SQLAlchemy/TLS settings if you need to supply a CA bundle. - Data scope: This switches orchestration data (flows, deployments, runs, logs, events) to Postgres. Task/flow result payloads are controlled by the Results configuration separately. Docs - Self-hosting Prefect 3: Self-hosted guide - Settings reference: Settings reference Do you need to migrate your existing run history from SQLite to Postgres or is a fresh start okay? There isn’t an official automated migration from SQLite → Postgres; if you need to keep history, I can outline options and caveats for a manual migration.