FATAL: database "myapp" does not exist — how to fix

psql: error: connection to server on socket "/var/run/postgresql/.s.PGSQL.5432" failed: FATAL:  database "myapp" does not exist
django.db.utils.OperationalError: connection to server at "localhost" (127.0.0.1), port 5432 failed: FATAL:  database "myapp" does not exist

Quick fix: Create it: createdb myapp or sudo -u postgres createdb -O myuser myapp (or CREATE DATABASE myapp OWNER myuser; in psql). If psql says the database named after your user doesn't exist, connect to an existing one: psql -d postgres. List databases with psql -l. Names are case-sensitive if created with quotes.

What it means

PostgreSQL connections always target one database. The server accepted the connection and the login, then couldn't find the database named in the connection string. Databases are per server (cluster), so the same name may exist on one host/port and not another.

List what exists on the server you're connecting to:

psql -h localhost -U myuser -d postgres -l
# or inside psql
\l

Cause 1: the database was never created

Create it, owned by the role your app uses:

sudo -u postgres createdb -O myuser myapp

or in SQL:

CREATE DATABASE myapp OWNER myuser;

Frameworks generally don't create the database for you on first connect: Rails has bin/rails db:create, Django and most others expect it to exist.

Cause 2: psql defaults to your username as the database

Running plain psql as user alice tries to connect to database alice:

psql: error: ... FATAL:  database "alice" does not exist

Connect to the default postgres database instead (it always exists on a fresh install):

psql -d postgres

Or create a database named after yourself so plain psql works: createdb alice. You can also set PGDATABASE=postgres in your environment.

Cause 3: Docker's POSTGRES_DB only applies on first start

The official image creates POSTGRES_DB (default: the value of POSTGRES_USER) only when the data directory is empty. If the volume already existed, changing POSTGRES_DB later does nothing.

# create it in the running container
docker exec -it db psql -U postgres -c "CREATE DATABASE myapp;"

# or, if the data is disposable, recreate the volume
docker compose down -v
docker compose up -d

down -v deletes the database volume and all data in it.

Cause 4: wrong server, port or container

You may have two PostgreSQL instances (a local install on 5432 and a Docker one, or two versions on 5432 and 5433). The database exists on one, your app connects to the other. Check:

sudo ss -ltnp | grep 543
psql "postgresql://myuser@localhost:5432/postgres" -c "select version(), inet_server_port();"

From inside a Docker Compose service, localhost is the container itself; use the service name (host=db).

Cause 5: case and quoting

Unquoted identifiers are folded to lowercase. CREATE DATABASE MyApp; creates myapp. But a tool that created "MyApp" with quotes made a mixed-case name, and connecting to myapp fails. Use the exact name shown by \l, and prefer lowercase names.

Cause 6: typo in the connection URL

Check the path part of the URL: in postgresql://user:pass@host:5432/myapp?sslmode=require, the database is myapp. A trailing space or a missing /dbname (which makes it default to the username) is a common mistake in .env files.

Last updated 2026-11-01.