diff --git a/docker/Dockerfile b/docker/Dockerfile
index d366ac9..28b6257 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -29,6 +29,7 @@ ARG NEXT_PUBLIC_SENTRY_DSN
 ARG SENTRY_ORG
 ARG SENTRY_PROJECT
 ARG SENTRY_AUTH_TOKEN
+ARG SENTRY_RELEASE
 
 ENV NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY=$NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY
 ENV NEXT_PUBLIC_SUPABASE_URL=$NEXT_PUBLIC_SUPABASE_URL
@@ -36,6 +37,7 @@ ENV NEXT_PUBLIC_SENTRY_DSN=$NEXT_PUBLIC_SENTRY_DSN
 ENV SENTRY_ORG=$SENTRY_ORG
 ENV SENTRY_PROJECT=$SENTRY_PROJECT
 ENV SENTRY_AUTH_TOKEN=$SENTRY_AUTH_TOKEN
+ENV SENTRY_RELEASE=$SENTRY_RELEASE
 ENV NEXT_TELEMETRY_DISABLED=1
 
 RUN npx prisma generate
diff --git a/docker/docker-compose.yml b/docker/docker-compose.yml
index b677114..e9efe37 100644
--- a/docker/docker-compose.yml
+++ b/docker/docker-compose.yml
@@ -24,6 +24,12 @@ services:
         SENTRY_ORG: ${SENTRY_ORG}
         SENTRY_PROJECT: ${SENTRY_PROJECT}
         SENTRY_AUTH_TOKEN: ${SENTRY_AUTH_TOKEN}
+        # Resolves the sourcemap upload's release name. .git is excluded from
+        # the build context (see .dockerignore), so @sentry/nextjs can't
+        # auto-detect it via git and falls back to a literal "undefined"
+        # string, which GlitchTip's sourcemaps upload rejects. start.sh sets
+        # this from `git rev-parse --short HEAD` on the host before building.
+        SENTRY_RELEASE: ${SENTRY_RELEASE}
     image: pawfeed:latest
     container_name: pawfeed
     restart: unless-stopped
diff --git a/docker/start.sh b/docker/start.sh
index a288a8f..4ce1a34 100644
--- a/docker/start.sh
+++ b/docker/start.sh
@@ -11,5 +11,10 @@ if [ ! -f .env ]; then
   exit 1
 fi
 
+# Sentry/GlitchTip sourcemap upload needs a release name at build time.
+# .git is excluded from the Docker build context, so it's resolved here
+# on the host (where .git exists) and passed through as a build arg.
+export SENTRY_RELEASE="$(git -C .. rev-parse --short HEAD)"
+
 docker compose up -d --build
 echo "PawFeed is starting on http://localhost:4563"