diff --git a/developer/src/inst/node/kmc.cmd b/developer/src/inst/node/kmc.cmd
index c1ac96270f..c529011171 100644
--- a/developer/src/inst/node/kmc.cmd
+++ b/developer/src/inst/node/kmc.cmd
@@ -1,4 +1,4 @@
 @rem This script avoids path dependencies for node for distribution
 @rem with Keyman Developer. When used on platforms other than Windows,
 @rem node can be used directly with the compiler (`npm link` will setup).
-@"%~dp0\node.js\node.exe" --enable-source-maps "%~dp0\kmc\kmc.cjs" %*
+@"%~dp0\node.js\node.exe" "%~dp0\kmc\kmc.mjs" %*
diff --git a/developer/src/inst/node/kmlmc.cmd b/developer/src/inst/node/kmlmc.cmd
index 81b87c0f9e..be3bdf06e0 100644
--- a/developer/src/inst/node/kmlmc.cmd
+++ b/developer/src/inst/node/kmlmc.cmd
@@ -1,4 +1,4 @@
 @rem This script avoids path dependencies for node for distribution
 @rem with Keyman Developer. When used on platforms other than Windows,
 @rem node can be used directly with the compiler (`npm link` will setup).
-@"%~dp0\node.js\node.exe" --enable-source-maps "%~dp0\kmc\kmlmc.cjs" %*
+@"%~dp0\node.js\node.exe" "%~dp0\kmc\kmlmc.mjs" %*
diff --git a/developer/src/inst/node/kmlmi.cmd b/developer/src/inst/node/kmlmi.cmd
index c02a72891c..e674fe4d2c 100644
--- a/developer/src/inst/node/kmlmi.cmd
+++ b/developer/src/inst/node/kmlmi.cmd
@@ -1,4 +1,4 @@
 @rem This script avoids path dependencies for node for distribution
 @rem with Keyman Developer. When used on platforms other than Windows,
 @rem node can be used directly with the compiler (`npm link` will setup).
-@"%~dp0\node.js\node.exe" --enable-source-maps "%~dp0\kmc\kmlmi.cjs" %*
+@"%~dp0\node.js\node.exe" "%~dp0\kmc\kmlmi.mjs" %*
diff --git a/developer/src/inst/node/kmlmp.cmd b/developer/src/inst/node/kmlmp.cmd
index 8994cf4db3..2062ae091c 100644
--- a/developer/src/inst/node/kmlmp.cmd
+++ b/developer/src/inst/node/kmlmp.cmd
@@ -1,4 +1,4 @@
 @rem This script avoids path dependencies for node for distribution
 @rem with Keyman Developer. When used on platforms other than Windows,
 @rem node can be used directly with the compiler (`npm link` will setup).
-@"%~dp0\node.js\node.exe" --enable-source-maps "%~dp0\kmc\kmlmp.cjs" %*
+@"%~dp0\node.js\node.exe" "%~dp0\kmc\kmlmp.mjs" %*
diff --git a/developer/src/kmc-model/build.sh b/developer/src/kmc-model/build.sh
index ecf58e20e4..2e73366b6b 100755
--- a/developer/src/kmc-model/build.sh
+++ b/developer/src/kmc-model/build.sh
@@ -32,7 +32,6 @@ builder_parse "$@"
 #-------------------------------------------------------------------------------------------------------------------
 
 function do_build() {
-  mkdir -p build/cjs-src
   npm run build
 }
 
diff --git a/developer/src/kmc/build-bundler.js b/developer/src/kmc/build-bundler.js
new file mode 100644
index 0000000000..5d55ee4be3
--- /dev/null
+++ b/developer/src/kmc/build-bundler.js
@@ -0,0 +1,32 @@
+/*
+ * Bundle kmc as esm with appropriate node modules and banner
+ */
+
+import esbuild from 'esbuild';
+
+await esbuild.build({
+  entryPoints: [
+    'build/src/kmc.js',
+    'build/src/kmlmc.js',
+    'build/src/kmlmi.js',
+    'build/src/kmlmp.js',
+  ],
+  bundle: true,
+  format: 'esm',
+  platform: 'node',
+  target: 'es2022',
+  outdir: 'build/dist/',
+
+  // We want a .mjs extension to force node into ESM module mode
+  outExtension: { '.js': '.mjs' },
+
+  // Thunk for external modules such as Commander that are still CJS and still
+  // use require, __filename, __dirname
+  banner: {
+    js: `
+      const require = (await import("node:module")).createRequire(import.meta.url);
+      const __filename = (await import("node:url")).fileURLToPath(import.meta.url);
+      const __dirname = (await import("node:path")).dirname(__filename);
+    `,
+  },
+});
diff --git a/developer/src/kmc/build.sh b/developer/src/kmc/build.sh
index 2ec2c57377..d5d5e80a66 100755
--- a/developer/src/kmc/build.sh
+++ b/developer/src/kmc/build.sh
@@ -56,13 +56,20 @@ fi
 
 function copy_schemas() {
   # We need the schema file at runtime and bundled, so always copy it for all actions except `clean`
+  local schemas=(
+    "$KEYMAN_ROOT/resources/standards-data/ldml-keyboards/techpreview/ldml-keyboard.schema.json"
+    "$KEYMAN_ROOT/resources/standards-data/ldml-keyboards/techpreview/ldml-keyboardtest.schema.json"
+    "$KEYMAN_ROOT/common/schemas/kvks/kvks.schema.json"
+    "$KEYMAN_ROOT/common/schemas/kpj/kpj.schema.json"
+    "$KEYMAN_ROOT/common/schemas/kpj-9.0/kpj-9.0.schema.json"
+    "$KEYMAN_ROOT/common/schemas/displaymap/displaymap.schema.json"
+  )
+
   mkdir -p "$THIS_SCRIPT_PATH/build/src/util/"
-  cp "$KEYMAN_ROOT/resources/standards-data/ldml-keyboards/techpreview/ldml-keyboard.schema.json" "$THIS_SCRIPT_PATH/build/src/util/"
-  cp "$KEYMAN_ROOT/resources/standards-data/ldml-keyboards/techpreview/ldml-keyboardtest.schema.json" "$THIS_SCRIPT_PATH/build/src/util/"
-  cp "$KEYMAN_ROOT/common/schemas/kvks/kvks.schema.json" "$THIS_SCRIPT_PATH/build/src/util/"
-  cp "$KEYMAN_ROOT/common/schemas/kpj/kpj.schema.json" "$THIS_SCRIPT_PATH/build/src/util/"
-  cp "$KEYMAN_ROOT/common/schemas/kpj-9.0/kpj-9.0.schema.json" "$THIS_SCRIPT_PATH/build/src/util/"
-  cp "$KEYMAN_ROOT/common/schemas/displaymap/displaymap.schema.json" "$THIS_SCRIPT_PATH/build/src/util/"
+  cp "${schemas[@]}" "$THIS_SCRIPT_PATH/build/src/util/"
+
+  mkdir -p "$THIS_SCRIPT_PATH/build/dist/"
+  cp "${schemas[@]}" "$THIS_SCRIPT_PATH/build/dist/"
 }
 
 #-------------------------------------------------------------------------------------------------------------------
@@ -94,16 +101,21 @@ fi
 #-------------------------------------------------------------------------------------------------------------------
 
 if builder_start_action bundle; then
-  copy_schemas
 
   if ! builder_has_option --build-path; then
     builder_finish_action "Parameter --build-path is required" bundle
     exit 64
   fi
 
-  mkdir -p build/cjs-src
-  npm run bundle
-  cp build/cjs-src/* "$BUILD_PATH"
+  rm -rf build/dist
+  mkdir -p build/dist
+  node build-bundler.js
+
+  # Manually copy over kmcmplib module and schemas
+  copy_schemas
+  cp ../kmc-kmn/build/src/import/kmcmplib/wasm-host.wasm build/dist/
+
+  cp build/dist/* "$BUILD_PATH"
 
   builder_finish_action success bundle
 fi
diff --git a/developer/src/kmc/src/commands/analyze.ts b/developer/src/kmc/src/commands/analyze.ts
index 3a71d2008e..d71f58afe8 100644
--- a/developer/src/kmc/src/commands/analyze.ts
+++ b/developer/src/kmc/src/commands/analyze.ts
@@ -1,7 +1,7 @@
 import * as fs from 'fs';
 import * as path from 'path';
 import { Command, Option } from 'commander';
-import { NodeCompilerCallbacks } from '../messages/NodeCompilerCallbacks.js';
+import { NodeCompilerCallbacks } from '../util/NodeCompilerCallbacks.js';
 import { InfrastructureMessages } from '../messages/messages.js';
 import { CompilerCallbacks, CompilerLogLevel } from '@keymanapp/common-types';
 import { AnalyzeOskCharacterUse, AnalyzeOskRewritePua } from '@keymanapp/kmc-analyze';
diff --git a/developer/src/kmc/src/commands/build.ts b/developer/src/kmc/src/commands/build.ts
index ddd916f34d..fade2070dd 100644
--- a/developer/src/kmc/src/commands/build.ts
+++ b/developer/src/kmc/src/commands/build.ts
@@ -2,7 +2,7 @@ import * as fs from 'fs';
 import { Command } from 'commander';
 import { buildActivities } from './buildClasses/buildActivities.js';
 import { BuildProject } from './buildClasses/BuildProject.js';
-import { NodeCompilerCallbacks } from '../messages/NodeCompilerCallbacks.js';
+import { NodeCompilerCallbacks } from '../util/NodeCompilerCallbacks.js';
 import { InfrastructureMessages } from '../messages/messages.js';
 import { CompilerFileCallbacks, CompilerOptions, KeymanFileTypes } from '@keymanapp/common-types';
 import { BaseOptions } from '../util/baseOptions.js';
diff --git a/developer/src/kmc/src/commands/buildTestData/index.ts b/developer/src/kmc/src/commands/buildTestData/index.ts
index d3c2e98d94..b50c63c1d6 100644
--- a/developer/src/kmc/src/commands/buildTestData/index.ts
+++ b/developer/src/kmc/src/commands/buildTestData/index.ts
@@ -2,7 +2,7 @@ import * as fs from 'fs';
 import * as path from 'path';
 import * as kmcLdml from '@keymanapp/kmc-ldml';
 import { CompilerBaseOptions, CompilerCallbacks, defaultCompilerOptions, LDMLKeyboardTestDataXMLSourceFile, LDMLKeyboardXMLSourceFileReader } from '@keymanapp/common-types';
-import { NodeCompilerCallbacks } from '../../messages/NodeCompilerCallbacks.js';
+import { NodeCompilerCallbacks } from '../../util/NodeCompilerCallbacks.js';
 import { fileURLToPath } from 'url';
 
 export function buildTestData(infile: string, options: CompilerBaseOptions) {
diff --git a/developer/src/kmc/src/kmlmc.ts b/developer/src/kmc/src/kmlmc.ts
index c021fb9384..1ce171fd15 100644
--- a/developer/src/kmc/src/kmlmc.ts
+++ b/developer/src/kmc/src/kmlmc.ts
@@ -8,7 +8,7 @@ import { Command } from 'commander';
 import { compileModel } from '@keymanapp/kmc-model';
 import { SysExits } from './util/sysexits.js';
 import KEYMAN_VERSION from "@keymanapp/keyman-version";
-import { NodeCompilerCallbacks } from './messages/NodeCompilerCallbacks.js';
+import { NodeCompilerCallbacks } from './util/NodeCompilerCallbacks.js';
 
 let inputFilename: string;
 const program = new Command();
diff --git a/developer/src/kmc/src/kmlmi.ts b/developer/src/kmc/src/kmlmi.ts
index f64ebb66f6..159dad38e0 100644
--- a/developer/src/kmc/src/kmlmi.ts
+++ b/developer/src/kmc/src/kmlmi.ts
@@ -9,7 +9,7 @@ import { KmpCompiler, PackageValidation } from '@keymanapp/kmc-package';
 import { ModelInfoOptions, writeMergedModelMetadataFile } from '@keymanapp/kmc-model-info';
 import { SysExits } from './util/sysexits.js';
 import KEYMAN_VERSION from "@keymanapp/keyman-version";
-import { NodeCompilerCallbacks } from './messages/NodeCompilerCallbacks.js';
+import { NodeCompilerCallbacks } from './util/NodeCompilerCallbacks.js';
 
 let inputFilename: string;
 const program = new Command();
diff --git a/developer/src/kmc/src/kmlmp.ts b/developer/src/kmc/src/kmlmp.ts
index a866b231f5..d02420eeca 100644
--- a/developer/src/kmc/src/kmlmp.ts
+++ b/developer/src/kmc/src/kmlmp.ts
@@ -10,7 +10,7 @@ import { Command } from 'commander';
 import { PackageValidation, KmpCompiler } from '@keymanapp/kmc-package';
 import { SysExits } from './util/sysexits.js';
 import KEYMAN_VERSION from "@keymanapp/keyman-version";
-import { NodeCompilerCallbacks } from './messages/NodeCompilerCallbacks.js';
+import { NodeCompilerCallbacks } from './util/NodeCompilerCallbacks.js';
 
 let inputFilename: string;
 const program = new Command();
diff --git a/developer/src/kmc/src/util/KeymanSentry.ts b/developer/src/kmc/src/util/KeymanSentry.ts
index 2d0844f04d..a2a466b83d 100644
--- a/developer/src/kmc/src/util/KeymanSentry.ts
+++ b/developer/src/kmc/src/util/KeymanSentry.ts
@@ -1,5 +1,5 @@
 import { KmnCompiler } from "@keymanapp/kmc-kmn";
-import { NodeCompilerCallbacks } from "../messages/NodeCompilerCallbacks.js";
+import { NodeCompilerCallbacks } from "./NodeCompilerCallbacks.js";
 import Sentry from "@sentry/node";
 import KEYMAN_VERSION from "@keymanapp/keyman-version";
 import { spawnChild } from "./spawnAwait.js";
diff --git a/developer/src/kmc/src/messages/NodeCompilerCallbacks.ts b/developer/src/kmc/src/util/NodeCompilerCallbacks.ts
similarity index 97%
rename from developer/src/kmc/src/messages/NodeCompilerCallbacks.ts
rename to developer/src/kmc/src/util/NodeCompilerCallbacks.ts
index 376ef5b6d9..53cd80243a 100644
--- a/developer/src/kmc/src/messages/NodeCompilerCallbacks.ts
+++ b/developer/src/kmc/src/util/NodeCompilerCallbacks.ts
@@ -6,7 +6,7 @@ import { CompilerCallbacks, CompilerSchema, CompilerEvent,
          CompilerError,
          CompilerCallbackOptions,
          CompilerFileCallbacks} from '@keymanapp/common-types';
-import { InfrastructureMessages } from './messages.js';
+import { InfrastructureMessages } from '../messages/messages.js';
 import chalk from 'chalk';
 import supportsColor from 'supports-color';
 
@@ -174,7 +174,7 @@ export class NodeCompilerCallbacks implements CompilerCallbacks {
   }
 
   loadSchema(schema: CompilerSchema): Uint8Array {
-    let schemaPath = new URL('../util/' + schema + '.schema.json', import.meta.url);
+    let schemaPath = new URL('./' + schema + '.schema.json', import.meta.url);
     return fs.readFileSync(schemaPath);
   }
 
diff --git a/developer/src/kmc/test/test-messages.ts b/developer/src/kmc/test/test-messages.ts
index d621cefbe9..57a460411d 100644
--- a/developer/src/kmc/test/test-messages.ts
+++ b/developer/src/kmc/test/test-messages.ts
@@ -3,7 +3,7 @@ import { assert } from 'chai';
 import { InfrastructureMessages } from '../src/messages/messages.js';
 import { verifyCompilerMessagesObject } from '@keymanapp/developer-test-helpers';
 import { makePathToFixture } from './helpers/index.js';
-import { NodeCompilerCallbacks } from '../src/messages/NodeCompilerCallbacks.js';
+import { NodeCompilerCallbacks } from './util/NodeCompilerCallbacks.js';
 import { CompilerErrorNamespace } from '@keymanapp/common-types';
 
 describe('InfrastructureMessages', function () {
diff --git a/web/common.inc.sh b/web/common.inc.sh
index 1dc057b1e9..e1594c911c 100644
--- a/web/common.inc.sh
+++ b/web/common.inc.sh
@@ -22,7 +22,7 @@ function compile() {
   local COMPILE_TARGET="$1"
   local BUNDLE_FLAG="${2:-}"
 
-  tsc -b "${KEYMAN_ROOT}/web/src/$COMPILE_TARGET" -v
+  tsc -b "${KEYMAN_ROOT}/web/src/$COMPILE_TARGET"
 
   if [ -f "./build-bundler.js" ]; then
     node "./build-bundler.js" "$BUNDLE_FLAG"