diff --git a/packages/service-bundler/README.md b/packages/service-bundler/README.md
index 7bb9bc79..c7c0a080 100644
--- a/packages/service-bundler/README.md
+++ b/packages/service-bundler/README.md
@@ -2,6 +2,11 @@
 
 Centralised script for bundling and zipping service artifacts for deployment.
 
+JavaScript is emitted as a single entry bundle per function and API proxy. This
+keeps Lambda artifacts self-contained and avoids runtime JavaScript chunk loading.
+Native `.node` assets, source maps, and files supplied through `copyFiles` are
+still emitted separately when required.
+
 ### Pre-requisites
 
 - Node.js (Please see `.nvmrc` for specific version)
diff --git a/packages/service-bundler/src/index.ts b/packages/service-bundler/src/index.ts
index 36397272..3ff7626b 100644
--- a/packages/service-bundler/src/index.ts
+++ b/packages/service-bundler/src/index.ts
@@ -97,6 +97,11 @@ export class ServicePackager {
 		mode: 'production',
 		optimization: {
 			minimize: true,
+			// Lambda handlers are deployed and loaded as self-contained artifacts.
+			// Keep the JavaScript graph in the entry chunk so the zip does not need
+			// Rspack's runtime chunk loader to resolve additional JS files.
+			splitChunks: false,
+			runtimeChunk: false,
 		},
 		ignoreWarnings: [
 			{
@@ -108,6 +113,7 @@ export class ServicePackager {
 		externals: ['@babel/core', /^@babel\//],
 		output: {
 			module: true,
+			asyncChunks: false,
 		},
 		module: {
 			rules: [