diff --git a/CHANGELOG.md b/CHANGELOG.md
index 904a13d3..dd828cda 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,8 @@ All notable changes to this project will be documented in this file.
 ## [Unreleased]
 
 - Fixed Calendar and Colibo feed configuration urls and added [] result when no locationEndpoint is set.
+- Fixed baked-in `.env` shipping `APP_ENV=dev` in the API image; rewritten to `prod` at build time so
+  direct reads don't try to bootstrap a dev environment the prod-only dependencies can't satisfy.
 
 ## [3.0.0-rc2] - 2026-05-05
 
diff --git a/infrastructure/display-api-service/Dockerfile b/infrastructure/display-api-service/Dockerfile
index de7dc6a1..66fc36bb 100644
--- a/infrastructure/display-api-service/Dockerfile
+++ b/infrastructure/display-api-service/Dockerfile
@@ -63,6 +63,12 @@ RUN APP_ENV=prod composer install --no-dev -o --classmap-authoritative --no-scri
 # rest of public/media/ — see the file for the preserved entries.
 COPY --chown=deploy:deploy --from=repository-root ./ ./
 
+# The committed .env defaults APP_ENV to dev for local development. The
+# image only ships prod dependencies (composer install --no-dev), so any
+# tooling that reads .env directly without our docker-entrypoint.sh
+# would bootstrap a dev environment that can't resolve its services.
+RUN sed -i 's/^APP_ENV=dev$/APP_ENV=prod/' .env
+
 # Vite manifest must be in place before the second composer install
 # triggers cache:clear, otherwise the vite bundle can't generate its
 # cache config files.