diff --git a/tools/@aws-cdk/cdk-build-tools/config/ext.js b/tools/@aws-cdk/cdk-build-tools/config/ext.js
new file mode 100644
index 0000000000000..4c5ae2090c8eb
--- /dev/null
+++ b/tools/@aws-cdk/cdk-build-tools/config/ext.js
@@ -0,0 +1,8 @@
+// In a separate file because this logic needs to be shared between files
+//
+// On developer boxes we want to run the .ts files directly for quickest
+// iteration (save -> run), but on CI machines we want to run the compiled
+// JavaScript for highest throughput.
+
+const isCi = !!process.env.CI || !!process.env.CODEBUILD_BUILD_ID;
+module.exports = isCi ? 'js' : 'ts';
\ No newline at end of file
diff --git a/tools/@aws-cdk/cdk-build-tools/config/jest.config.js b/tools/@aws-cdk/cdk-build-tools/config/jest.config.js
index 0c47026702afe..8a8d4f048cb79 100644
--- a/tools/@aws-cdk/cdk-build-tools/config/jest.config.js
+++ b/tools/@aws-cdk/cdk-build-tools/config/jest.config.js
@@ -1,3 +1,10 @@
+// Crazy stuff!
+//
+// On developer boxes we want to run the .ts files directly for quickest
+// iteration (save -> run), but on CI machines we want to run the compiled
+// JavaScript for highest throughput.
+const ext = require('./ext');
+
 const thisPackagesPackageJson = require(`${process.cwd()}/package.json`);
 const setupFilesAfterEnv = [];
 if ('aws-cdk-lib' in thisPackagesPackageJson.devDependencies ?? {}) {
@@ -5,7 +12,7 @@ if ('aws-cdk-lib' in thisPackagesPackageJson.devDependencies ?? {}) {
   setupFilesAfterEnv.push('aws-cdk-lib/testhelpers/jest-autoclean');
 } else if (thisPackagesPackageJson.name === 'aws-cdk-lib') {
   // If we *ARE* aws-cdk-lib, use the hook in a slightly different way
-  setupFilesAfterEnv.push('./testhelpers/jest-autoclean.ts');
+  setupFilesAfterEnv.push(`./testhelpers/jest-autoclean.${ext}`);
 }
 
 module.exports = {
@@ -15,7 +22,7 @@ module.exports = {
     'ts',
     'js',
   ],
-  testMatch: ['<rootDir>/test/**/?(*.)+(test).ts'],
+  testMatch: [`<rootDir>/test/**/?(*.)+(test).${ext}`],
 
   // Transform TypeScript using ts-jest. Use of this preset still requires the depending
   // package to depend on `ts-jest` directly.
@@ -43,4 +50,9 @@ module.exports = {
   reporters: ['default', ['jest-junit', { suiteName: 'jest tests', outputDirectory: 'coverage' }]],
 
   setupFilesAfterEnv,
+
+  // A consequence of doing this is that snapshots files are always named after
+  // the currently executing file, which will be different for .ts and .js
+  // extensions, so we need to do some more work to redirect always to .ts
+  snapshotResolver: `${__dirname}/snapshot-resolver.js`,
 };
diff --git a/tools/@aws-cdk/cdk-build-tools/config/snapshot-resolver.js b/tools/@aws-cdk/cdk-build-tools/config/snapshot-resolver.js
new file mode 100644
index 0000000000000..7c6061e2918ed
--- /dev/null
+++ b/tools/@aws-cdk/cdk-build-tools/config/snapshot-resolver.js
@@ -0,0 +1,20 @@
+const path = require('path');
+const ext = require('./ext');
+
+const dotext = `.${ext}`;
+
+module.exports = {
+  // resolves from test to snapshot path
+  resolveSnapshotPath: (testPath, snapshotExtension) => {
+    return `${path.dirname(testPath)}/__snapshots__/${path.basename(testPath, dotext)}.ts${snapshotExtension}`;
+  },
+
+  // resolves from snapshot to test path
+  resolveTestPath: (snapshotFilePath, snapshotExtension) => {
+    const testDir = path.dirname(path.dirname(snapshotFilePath));
+    return `${testDir}/${path.basename(snapshotFilePath, `.ts${snapshotExtension}`)}${dotext}`;
+  },
+
+  // Example test path, used for preflight consistency check of the implementation above
+  testPathForConsistencyCheck: `test/apple.test.${dotext}`,
+};
\ No newline at end of file
diff --git a/tools/@aws-cdk/construct-metadata-updater/test/metadata-updater.test.ts b/tools/@aws-cdk/construct-metadata-updater/test/metadata-updater.test.ts
index 018622975c1bb..65f4639e3cac7 100644
--- a/tools/@aws-cdk/construct-metadata-updater/test/metadata-updater.test.ts
+++ b/tools/@aws-cdk/construct-metadata-updater/test/metadata-updater.test.ts
@@ -1,8 +1,3 @@
-import { ConstructsUpdater, EnumLikeUpdater, PropertyUpdater } from '../lib/metadata-updater';
-import { Project, ClassDeclaration, SourceFile, QuoteKind, IndentationText } from 'ts-morph';
-import * as path from 'path';
-import * as fs from 'fs';
-
 // Mock ts-morph
 jest.mock('ts-morph');
 // Mock fs
@@ -10,6 +5,11 @@ jest.mock('fs');
 // Mock path
 jest.mock('path');
 
+import { ConstructsUpdater, EnumLikeUpdater, PropertyUpdater } from '../lib/metadata-updater';
+import { Project, ClassDeclaration, SourceFile, QuoteKind, IndentationText } from 'ts-morph';
+import * as path from 'path';
+import * as fs from 'fs';
+
 describe('ResourceMetadataUpdater', () => {
   let updater: ConstructsUpdater;
   let mockSourceFile: jest.Mocked<SourceFile>;