diff --git a/.gitignore b/.gitignore
index 104af9a157ef..47c2fc037ca4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -54,6 +54,7 @@ workspace
 
 .turbo
 turbo.dev.json
+.rollup.cache
 coverage
 dist-*
 
diff --git a/package.json b/package.json
index 8f2193b81963..47e123d71f08 100644
--- a/package.json
+++ b/package.json
@@ -73,6 +73,9 @@
     "@fastify/formbody": "^7.4.0",
     "@microsoft/api-extractor": "7.52.7",
     "@mixer/parallel-prettier": "2.0.3",
+    "@rollup/plugin-json": "^6.1.0",
+    "@rollup/plugin-node-resolve": "^16.0.2",
+    "@rollup/plugin-typescript": "^12.1.4",
     "@tsconfig/recommended": "1.0.1",
     "@types/fs-extra": "^8.0.1",
     "@types/jest": "29.5.11",
diff --git a/scripts/compilation/Inliner.js b/scripts/compilation/Inliner.js
index 580a236da389..12d4b2efdb16 100644
--- a/scripts/compilation/Inliner.js
+++ b/scripts/compilation/Inliner.js
@@ -2,7 +2,10 @@ const fs = require("fs");
 const path = require("path");
 const { spawnProcess } = require("./../utils/spawn-process");
 const walk = require("./../utils/walk");
-const esbuild = require("esbuild");
+const rollup = require("rollup");
+const { nodeResolve } = require("@rollup/plugin-node-resolve");
+const typescript = require("@rollup/plugin-typescript");
+const json = require("@rollup/plugin-json");
 
 const root = path.join(__dirname, "..", "..");
 
@@ -143,6 +146,8 @@ module.exports = class Inliner {
       }
     }
 
+    this.variantExternals = [...new Set(this.variantExternals)];
+
     return this;
   }
 
@@ -155,30 +160,67 @@ module.exports = class Inliner {
       return this;
     }
 
-    this.variantExternalsForEsBuild = this.variantExternals.map(
-      (variant) => "*/" + path.basename(variant).replace(/.js$/, "")
-    );
+    const variantExternalsForRollup = this.variantExternals.map((variant) => variant.replace(/.js$/, ""));
+
+    const entryPoint = path.join(root, this.subfolder, this.package, "src", "index.ts");
+
+    const inputOptions = (externals) => ({
+      input: [entryPoint],
+      plugins: [
+        nodeResolve(),
+        json(),
+        typescript({
+          compilerOptions: {
+            importHelpers: true,
+            noEmitHelpers: false,
+            module: "esnext",
+            target: "es2022",
+            noCheck: true,
+            removeComments: true,
+          },
+        }),
+      ],
+      external: (id) => {
+        const relative = !!id.match(/^\.?\.?\//);
+        if (!relative) {
+          this.verbose && console.log("EXTERN (pkg)", id);
+          return true;
+        }
 
-    const buildOptions = {
-      platform: this.platform,
-      target: ["node18"],
-      bundle: true,
-      format: "cjs",
-      mainFields: ["main"],
-      allowOverwrite: true,
-      entryPoints: [path.join(root, this.subfolder, this.package, "src", "index.ts")],
-      supported: {
-        "dynamic-import": false,
+        const local = id.includes(`/packages/`) && id.includes(`/dist-es/`);
+        if (local) {
+          this.verbose && console.log("EXTERN (local)", id);
+          return true;
+        }
+
+        if (id === entryPoint) {
+          this.verbose && console.log("INTERN (entry point)", id);
+          return false;
+        }
+
+        for (const file of externals) {
+          const idWithoutExtension = id.replace(/\.ts$/, "");
+          if (idWithoutExtension.endsWith(path.basename(file))) {
+            this.verbose && console.log("EXTERN (variant)", id);
+            return true;
+          }
+        }
+
+        this.verbose && console.log("INTERN (invariant)", id);
+        return false;
       },
-      outfile: this.outfile,
-      keepNames: true,
-      packages: "external",
-      external: ["@smithy/*", "@aws-sdk/*", "node_modules/*", ...this.variantExternalsForEsBuild],
+    });
+
+    const outputOptions = {
+      dir: path.dirname(this.outfile),
+      format: "cjs",
+      exports: "named",
+      preserveModules: false,
     };
 
-    if (!this.hasSubmodules) {
-      await esbuild.build(buildOptions);
-    }
+    const bundle = await rollup.rollup(inputOptions(variantExternalsForRollup));
+    await bundle.write(outputOptions);
+    await bundle.close();
 
     if (this.hasSubmodules) {
       const submodules = fs.readdirSync(path.join(root, this.subfolder, this.package, "src", "submodules"));
@@ -206,19 +248,41 @@ module.exports = class Inliner {
           }
         }
 
-        await esbuild.build({
-          ...buildOptions,
-          entryPoints: [path.join(root, this.subfolder, this.package, "src", "submodules", submodule, "index.ts")],
-          outfile: path.join(root, this.subfolder, this.package, "dist-cjs", "submodules", submodule, "index.js"),
-          external: [
-            "@smithy/*",
-            "@aws-sdk/*",
-            "node_modules/*",
-            ...this.variantExternals
-              .filter((variant) => variant.includes(`submodules/${submodule}`))
-              .map((variant) => "*/" + path.basename(variant).replace(/.js$/, "")),
-          ],
+        // remove remaining empty directories.
+        const submoduleFolder = path.join(root, this.subfolder, this.package, "dist-cjs", "submodules", submodule);
+        function rmdirEmpty(dir) {
+          for (const entry of fs.readdirSync(dir)) {
+            const fullPath = path.join(dir, entry);
+            if (fs.lstatSync(fullPath).isDirectory()) {
+              if (fs.readdirSync(fullPath).length) {
+                rmdirEmpty(fullPath);
+              } else {
+                fs.rmdirSync(fullPath);
+              }
+            }
+          }
+        }
+        rmdirEmpty(submoduleFolder);
+
+        const submoduleVariants = variantExternalsForRollup.filter((external) =>
+          external.includes(`submodules/${submodule}`)
+        );
+
+        const submoduleOptions = inputOptions(submoduleVariants);
+
+        const submoduleBundle = await rollup.rollup({
+          ...submoduleOptions,
+          input: path.join(root, this.subfolder, this.package, "src", "submodules", submodule, "index.ts"),
+        });
+
+        await submoduleBundle.write({
+          ...outputOptions,
+          dir: path.dirname(
+            path.join(root, this.subfolder, this.package, "dist-cjs", "submodules", submodule, "index.js")
+          ),
         });
+
+        await submoduleBundle.close();
       }
     }
 
@@ -271,7 +335,9 @@ module.exports = class Inliner {
               .join("/")) + "/index.js";
 
       if (!this.reExportStubs) {
-        fs.rmSync(file);
+        if (fs.readFileSync(file, "utf-8").includes(`Object.defineProperty(exports, "__esModule", { value: true });`)) {
+          fs.rmSync(file);
+        }
         const files = fs.readdirSync(path.dirname(file));
         if (files.length === 0) {
           fs.rmdirSync(path.dirname(file));
@@ -463,33 +529,51 @@ module.exports = class Inliner {
     }
 
     // check ESM compat.
-    const tmpFileContents = this.canonicalExports
-      .filter((sym) => !sym.includes(":"))
-      .map((sym) => `import { ${sym} } from "${this.pkgJson.name}";`)
-      .join("\n");
+    const tmpFileContents =
+      `import assert from "node:assert";
+      
+      const namingExceptions = [
+        "paginateOperation" // name for all paginators.
+      ];
+      ` +
+      this.canonicalExports
+        .filter((sym) => !sym.includes(":"))
+        .map((sym) => {
+          if (
+            [
+              "AWSSDKSigV4Signer", // deprecated alias for AwsSdkSigV4Signer
+              "resolveAWSSDKSigV4Config", // deprecated alias for resolveAwsSdkSigV4Config
+              "__Client", // base Client in SDK clients
+              "$Command", // base Command in SDK clients
+              "getDefaultClientConfiguration", // renamed to getDefaultExtensionConfiguration
+              "generateIdempotencyToken", // sometimes called v4
+              "defaultUserAgent", // renamed to createDefaultUserAgentProvider
+              "getSigV4AuthPlugin", // legacy auth, getAwsAuthPlugin
+              "NumberValueImpl", // name of NumberValue
+
+              "WorkSpacesThin", // alias of WorkSpacesThinClient
+
+              "HostResolver", // alias of NodeDnsLookupHostResolver
+              "expectInt", // aliased to expectLong
+              "handleFloat", // aliased to limitedParseDouble
+              "limitedParseFloat", // aliased to limitedParseDouble
+              "strictParseFloat", // aliased to strictParseDouble
+              "strictParseInt", // aliased to strictParseLong
+            ].includes(sym)
+          ) {
+            return `import { ${sym} } from "${this.pkgJson.name}";`;
+          }
+          return `import { ${sym} } from "${this.pkgJson.name}";
+if (typeof ${sym} === "function") {
+  if (${sym}.name !== "${sym}" && !namingExceptions.includes(${sym}.name)) {
+    throw new Error(${sym}.name + " does not equal expected ${sym}.")
+  }
+} 
+        `;
+        })
+        .join("\n");
     fs.writeFileSync(path.join(__dirname, "tmp", this.package + ".mjs"), tmpFileContents, "utf-8");
     await spawnProcess("node", [path.join(__dirname, "tmp", this.package + ".mjs")]);
-
-    if (this.hasSubmodules) {
-      const submodules = fs.readdirSync(path.join(root, this.subfolder, this.package, "src", "submodules"));
-      for (const submodule of submodules) {
-        const canonicalExports = Object.keys(
-          require(path.join(root, this.subfolder, this.package, "dist-cjs", "submodules", submodule, "index.js"))
-        );
-        const tmpFileContents = canonicalExports
-          .filter((sym) => !sym.includes(":"))
-          .map((sym) => `import { ${sym} } from "${this.pkgJson.name}/${submodule}";`)
-          .join("\n");
-        const tmpFilePath = path.join(__dirname, "tmp", this.package + "_" + submodule + ".mjs");
-        fs.writeFileSync(tmpFilePath, tmpFileContents, "utf-8");
-        await spawnProcess("node", [tmpFilePath]);
-        fs.rmSync(tmpFilePath);
-        if (this.verbose) {
-          console.log("ESM compatibility verified for submodule", submodule);
-        }
-      }
-    }
-
     if (this.verbose) {
       console.log("ESM compatibility verified.");
     }
diff --git a/yarn.lock b/yarn.lock
index 3c584b34df1d..9eb15138eea5 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -28332,6 +28332,73 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@rollup/plugin-json@npm:^6.1.0":
+  version: 6.1.0
+  resolution: "@rollup/plugin-json@npm:6.1.0"
+  dependencies:
+    "@rollup/pluginutils": "npm:^5.1.0"
+  peerDependencies:
+    rollup: ^1.20.0||^2.0.0||^3.0.0||^4.0.0
+  peerDependenciesMeta:
+    rollup:
+      optional: true
+  checksum: 10c0/9400c431b5e0cf3088ba2eb2d038809a2b0fb2a84ed004997da85582f48cd64958ed3168893c4f2c8109e38652400ed68282d0c92bf8ec07a3b2ef2e1ceab0b7
+  languageName: node
+  linkType: hard
+
+"@rollup/plugin-node-resolve@npm:^16.0.2":
+  version: 16.0.2
+  resolution: "@rollup/plugin-node-resolve@npm:16.0.2"
+  dependencies:
+    "@rollup/pluginutils": "npm:^5.0.1"
+    "@types/resolve": "npm:1.20.2"
+    deepmerge: "npm:^4.2.2"
+    is-module: "npm:^1.0.0"
+    resolve: "npm:^1.22.1"
+  peerDependencies:
+    rollup: ^2.78.0||^3.0.0||^4.0.0
+  peerDependenciesMeta:
+    rollup:
+      optional: true
+  checksum: 10c0/483b678a78decddb2597abcaf3b7e92c54c296a7362224ed6791bd7d46a7ee1cc0d652c96dadd0ea3b1f30d0f304b2bf7bb02b6748b6ba2067e7c157b8a8ca70
+  languageName: node
+  linkType: hard
+
+"@rollup/plugin-typescript@npm:^12.1.4":
+  version: 12.1.4
+  resolution: "@rollup/plugin-typescript@npm:12.1.4"
+  dependencies:
+    "@rollup/pluginutils": "npm:^5.1.0"
+    resolve: "npm:^1.22.1"
+  peerDependencies:
+    rollup: ^2.14.0||^3.0.0||^4.0.0
+    tslib: "*"
+    typescript: ">=3.7.0"
+  peerDependenciesMeta:
+    rollup:
+      optional: true
+    tslib:
+      optional: true
+  checksum: 10c0/b5bf7f54794d0b33ae5441c5aa202a95beb7068c206f40102f94997e888756c06c2bfe00517eb74a58771078432f94e8a34e99f5c6dbf89a22b49431b83c4798
+  languageName: node
+  linkType: hard
+
+"@rollup/pluginutils@npm:^5.0.1, @rollup/pluginutils@npm:^5.1.0":
+  version: 5.3.0
+  resolution: "@rollup/pluginutils@npm:5.3.0"
+  dependencies:
+    "@types/estree": "npm:^1.0.0"
+    estree-walker: "npm:^2.0.2"
+    picomatch: "npm:^4.0.2"
+  peerDependencies:
+    rollup: ^1.20.0||^2.0.0||^3.0.0||^4.0.0
+  peerDependenciesMeta:
+    rollup:
+      optional: true
+  checksum: 10c0/001834bf62d7cf5bac424d2617c113f7f7d3b2bf3c1778cbcccb72cdc957b68989f8e7747c782c2b911f1dde8257f56f8ac1e779e29e74e638e3f1e2cac2bcd0
+  languageName: node
+  linkType: hard
+
 "@rollup/rollup-android-arm-eabi@npm:4.46.2":
   version: 4.46.2
   resolution: "@rollup/rollup-android-arm-eabi@npm:4.46.2"
@@ -29711,6 +29778,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@types/resolve@npm:1.20.2":
+  version: 1.20.2
+  resolution: "@types/resolve@npm:1.20.2"
+  checksum: 10c0/c5b7e1770feb5ccfb6802f6ad82a7b0d50874c99331e0c9b259e415e55a38d7a86ad0901c57665d93f75938be2a6a0bc9aa06c9749192cadb2e4512800bbc6e6
+  languageName: node
+  linkType: hard
+
 "@types/semver@npm:^7.3.12":
   version: 7.5.8
   resolution: "@types/semver@npm:7.5.8"
@@ -30917,6 +30991,9 @@ __metadata:
     "@fastify/formbody": "npm:^7.4.0"
     "@microsoft/api-extractor": "npm:7.52.7"
     "@mixer/parallel-prettier": "npm:2.0.3"
+    "@rollup/plugin-json": "npm:^6.1.0"
+    "@rollup/plugin-node-resolve": "npm:^16.0.2"
+    "@rollup/plugin-typescript": "npm:^12.1.4"
     "@tsconfig/recommended": "npm:1.0.1"
     "@types/fs-extra": "npm:^8.0.1"
     "@types/jest": "npm:29.5.11"
@@ -33442,6 +33519,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"estree-walker@npm:^2.0.2":
+  version: 2.0.2
+  resolution: "estree-walker@npm:2.0.2"
+  checksum: 10c0/53a6c54e2019b8c914dc395890153ffdc2322781acf4bd7d1a32d7aedc1710807bdcd866ac133903d5629ec601fbb50abe8c2e5553c7f5a0afdd9b6af6c945af
+  languageName: node
+  linkType: hard
+
 "estree-walker@npm:^3.0.3":
   version: 3.0.3
   resolution: "estree-walker@npm:3.0.3"
@@ -35190,6 +35274,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"is-module@npm:^1.0.0":
+  version: 1.0.0
+  resolution: "is-module@npm:1.0.0"
+  checksum: 10c0/795a3914bcae7c26a1c23a1e5574c42eac13429625045737bf3e324ce865c0601d61aee7a5afbca1bee8cb300c7d9647e7dc98860c9bdbc3b7fdc51d8ac0bffc
+  languageName: node
+  linkType: hard
+
 "is-negated-glob@npm:^1.0.0":
   version: 1.0.0
   resolution: "is-negated-glob@npm:1.0.0"
@@ -39523,7 +39614,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"resolve@npm:^1.1.6, resolve@npm:^1.10.0, resolve@npm:^1.20.0, resolve@npm:^1.9.0, resolve@npm:~1.22.1, resolve@npm:~1.22.2":
+"resolve@npm:^1.1.6, resolve@npm:^1.10.0, resolve@npm:^1.20.0, resolve@npm:^1.22.1, resolve@npm:^1.9.0, resolve@npm:~1.22.1, resolve@npm:~1.22.2":
   version: 1.22.10
   resolution: "resolve@npm:1.22.10"
   dependencies:
@@ -39546,7 +39637,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"resolve@patch:resolve@npm%3A^1.1.6#optional!builtin<compat/resolve>, resolve@patch:resolve@npm%3A^1.10.0#optional!builtin<compat/resolve>, resolve@patch:resolve@npm%3A^1.20.0#optional!builtin<compat/resolve>, resolve@patch:resolve@npm%3A^1.9.0#optional!builtin<compat/resolve>, resolve@patch:resolve@npm%3A~1.22.1#optional!builtin<compat/resolve>, resolve@patch:resolve@npm%3A~1.22.2#optional!builtin<compat/resolve>":
+"resolve@patch:resolve@npm%3A^1.1.6#optional!builtin<compat/resolve>, resolve@patch:resolve@npm%3A^1.10.0#optional!builtin<compat/resolve>, resolve@patch:resolve@npm%3A^1.20.0#optional!builtin<compat/resolve>, resolve@patch:resolve@npm%3A^1.22.1#optional!builtin<compat/resolve>, resolve@patch:resolve@npm%3A^1.9.0#optional!builtin<compat/resolve>, resolve@patch:resolve@npm%3A~1.22.1#optional!builtin<compat/resolve>, resolve@patch:resolve@npm%3A~1.22.2#optional!builtin<compat/resolve>":
   version: 1.22.10
   resolution: "resolve@patch:resolve@npm%3A1.22.10#optional!builtin<compat/resolve>::version=1.22.10&hash=c3c19d"
   dependencies: