diff --git a/.esbuild/esbuild.cjs b/.esbuild/esbuild.cjs
index affd08ef9..e38951bdb 100644
--- a/.esbuild/esbuild.cjs
+++ b/.esbuild/esbuild.cjs
@@ -1,4 +1,4 @@
-const { esmBuild, iifeBuild } = require('./util.cjs');
+const { esmBuild, esmCoreBuild, iifeBuild } = require('./util.cjs');
 const { build } = require('esbuild');
 
 const handler = (e) => {
@@ -12,10 +12,9 @@ build(iifeBuild({ minify: false, watch })).catch(handler);
 // mermaid.esm.mjs
 build(esmBuild({ minify: false, watch })).catch(handler);
 
-// mermaid.core.js
-build(iifeBuild({ minify: false, core: true })).catch(handler);
-
 // mermaid.min.js
 build(esmBuild()).catch(handler);
 // mermaid.esm.min.mjs
 build(iifeBuild()).catch(handler);
+// mermaid.core.mjs (node_modules unbundled)
+build(esmCoreBuild()).catch(handler);
diff --git a/.esbuild/util.cjs b/.esbuild/util.cjs
index f22186fc2..10832474f 100644
--- a/.esbuild/util.cjs
+++ b/.esbuild/util.cjs
@@ -1,5 +1,6 @@
 const { Generator } = require('jison');
 const fs = require('fs');
+const { dependencies } = require('../package.json');
 
 /** @typedef {import('esbuild').BuildOptions} Options */
 
@@ -27,8 +28,12 @@ const buildOptions = (override = {}) => {
 };
 
 /**
- * @param {Options} override
- * @returns {Options}
+ * Build options for mermaid.esm.* build.
+ *
+ * For ESM browser use.
+ *
+ * @param {Options} override - Override options.
+ * @returns {Options} ESBuild build options.
  */
 exports.esmBuild = (override = { minify: true }) => {
   return buildOptions({
@@ -39,17 +44,35 @@ exports.esmBuild = (override = { minify: true }) => {
 };
 
 /**
- * @param {Options & { core?: boolean }} override
- * @returns {Options}
+ * Build options for mermaid.core.* build.
+ *
+ * This build does not bundle `./node_modules/`, as it is designed to be used
+ * with Webpack/ESBuild to merge webpack into a website.
+ *
+ * @param {Options} override - Override options.
+ * @returns {Options} ESBuild build options.
  */
-exports.iifeBuild = (override = { minify: true, core: false }) => {
-  const core = override.core;
-  if (core && override.minify) {
-    throw new Error('Cannot minify core build');
-  }
-  delete override.core;
+exports.esmCoreBuild = (override) => {
   return buildOptions({
-    outfile: `dist/mermaid${override.minify ? '.min' : core ? '.core' : ''}.js`,
+    format: 'esm',
+    outfile: `dist/mermaid.core.mjs`,
+    external: ['require', 'fs', 'path', ...Object.keys(dependencies)],
+    platform: 'neutral',
+    ...override,
+  });
+};
+
+/**
+ * Build options for mermaid.js build.
+ *
+ * For IIFE browser use (where ESM is not yet supported).
+ *
+ * @param {Options} override - Override options.
+ * @returns {Options} ESBuild build options.
+ */
+exports.iifeBuild = (override = { minify: true }) => {
+  return buildOptions({
+    outfile: `dist/mermaid${override.minify ? '.min' : ''}.js`,
     format: 'iife',
     ...override,
   });