diff --git a/Dockerfile b/Dockerfile
index 0c5d6e6..46d79b6 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -22,18 +22,21 @@ RUN npx prisma generate
 # Build the Next.js app
 RUN npm run build
 
-# Pre-compile the seed to a self-contained CJS bundle. Runtime then runs
-# plain `node prisma/seed-dow.cjs` and avoids the whole tsx+module-resolution
-# nightmare: Next.js's standalone node_modules was aggressively reshuffling
-# the tree after install, leaving packages like postgres-array with a
-# manifest but no index.js. Bundling sidesteps that entirely.
+# Pre-compile the seed to a self-contained ESM bundle. Runtime then runs
+# plain `node prisma/seed-dow.mjs` and avoids the whole tsx+module-
+# resolution nightmare: Next.js's standalone node_modules was aggressively
+# reshuffling the tree after install, leaving packages like postgres-array
+# with a manifest but no index.js. Bundling sidesteps that entirely.
 #
-# `--packages=external` keeps NPM packages (e.g. bcryptjs, @prisma/*) as
-# runtime require() calls so the bundle stays small and native .node files
+# ESM (not CJS) because Prisma's generated client uses `import.meta.url`
+# for engine detection — that's `undefined` in CJS and crashes on load.
+#
+# `--packages=external` keeps NPM packages (bcryptjs, @prisma/*) as
+# runtime import() calls so the bundle stays small and native .node files
 # in @prisma/client work normally.
 RUN npx -y esbuild@0.24 prisma/seed-dow.ts \
-      --bundle --platform=node --format=cjs --target=node22 \
-      --outfile=prisma/seed-dow.cjs \
+      --bundle --platform=node --format=esm --target=node22 \
+      --outfile=prisma/seed-dow.mjs \
       --packages=external
 
 # Production image