LocalStack companion for the Standard Notes self-hosted backend. Provides the SNS and SQS endpoints the standardnotes/server image expects at "localstack:4566". Required side container. Without it, files-worker.log fills with "SQSError: SQS receive message failed: getaddrinfo ENOTFOUND localstack" and notes can duplicate. Hostname resolution. The server resolves the literal name "localstack". Pick one: User-defined Docker network: put both containers on the same custom bridge and set this container's network alias to "localstack". Docker's embedded DNS handles the rest. br0 / macvlan / VLAN / static-IP install: assign this container a fixed IP on the same VLAN as StandardNotes-Server, then append --add-host=localstack:LocalStack-IP to StandardNotes-Server's Extra Parameters and restart it. Verify from the Unraid host: docker exec StandardNotes-Server getent hosts localstack Must print a non-empty line. Required init script. LocalStack starts empty. The server expects a fixed set of SNS topics and SQS queues. The "LocalStack Bootstrap Script" path mapping below mounts the bootstrap script into /etc/localstack/init/ready.d/ where LocalStack runs it on ready. Automatic bootstrap on container start runs ONLY when ALL THREE of the following are true at first start: a) the host file /mnt/user/appdata/standardnotes/localstack_bootstrap.sh exists, b) it is executable (chmod +x), c) the "LocalStack Bootstrap Script" Path mapping is left at its default (mapped to /etc/localstack/init/ready.d/localstack_bootstrap.sh). LocalStack's init/ready.d/ hook fires ONCE per container lifetime. If the script was missing on first start, restart the container or use the README emergency-bootstrap one-liner to populate it in place. Before first start, on the Unraid host: mkdir -p /mnt/user/appdata/standardnotes curl -fsSL -o /mnt/user/appdata/standardnotes/localstack_bootstrap.sh \ https://raw.githubusercontent.com/junkerderprovinz/standardnotes-server/main/scripts/localstack_bootstrap.sh chmod +x /mnt/user/appdata/standardnotes/localstack_bootstrap.sh Verify after start: docker exec StandardNotes-LocalStack awslocal \ --endpoint-url=http://localhost:4566 sqs list-queues docker exec StandardNotes-LocalStack awslocal \ --endpoint-url=http://localhost:4566 sns list-topics Both must list the *-local-queue / *-local-topic entries.