diff --git a/bazel/integration/test_runner/BUILD.bazel b/bazel/integration/test_runner/BUILD.bazel
index 5eeca4cc0..d19939ec2 100644
--- a/bazel/integration/test_runner/BUILD.bazel
+++ b/bazel/integration/test_runner/BUILD.bazel
@@ -8,6 +8,7 @@ ts_project(
     tsconfig = "//bazel:tsconfig",
     deps = [
         "//bazel:node_modules/@types/node",
+        "//bazel:node_modules/chalk",
         "//bazel:node_modules/true-case-path",
     ],
 )
diff --git a/bazel/integration/test_runner/runner.mts b/bazel/integration/test_runner/runner.mts
index 681ed525b..3ab11fd9a 100644
--- a/bazel/integration/test_runner/runner.mts
+++ b/bazel/integration/test_runner/runner.mts
@@ -30,6 +30,7 @@ import {
 } from './process_utils.mjs';
 import {ENVIRONMENT_TMP_PLACEHOLDER} from './constants.mjs';
 import {debug} from './debug.mjs';
+import {SizeTracker} from './size-tracking.mjs';
 
 /** Error class that is used when an integration command fails.  */
 class IntegrationTestCommandError extends Error {}
@@ -47,6 +48,7 @@ type EnvironmentConfig = Record<string, BazelExpandedValue>;
  */
 export class TestRunner {
   private readonly environment: EnvironmentConfig;
+  private readonly sizeTracker: SizeTracker;
 
   constructor(
     private readonly isTestDebugMode: boolean,
@@ -59,6 +61,7 @@ export class TestRunner {
     environment: EnvironmentConfig,
   ) {
     this.environment = this._assignDefaultEnvironmentVariables(environment);
+    this.sizeTracker = new SizeTracker(this.testPackage);
   }
 
   async run() {
@@ -82,6 +85,7 @@ export class TestRunner {
 
     try {
       await this._runTestCommands(testWorkingDir, testEnv);
+      await this.sizeTracker.run(testWorkingDir, testEnv);
     } finally {
       debug('Finished running integration test commands.');
 
diff --git a/bazel/integration/test_runner/size-tracking.mts b/bazel/integration/test_runner/size-tracking.mts
new file mode 100644
index 000000000..450424825
--- /dev/null
+++ b/bazel/integration/test_runner/size-tracking.mts
@@ -0,0 +1,124 @@
+/**
+ * @license
+ * Copyright Google LLC
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import {runCommandInChildProcess} from './process_utils.mjs';
+import {existsSync} from 'node:fs';
+import fs from 'node:fs/promises';
+import path from 'node:path';
+import chalk from 'chalk';
+import {debug} from './debug.mjs';
+
+// Convience access to chalk colors.
+const {red, green} = chalk;
+/** The size discrepancy we allow in bytes. */
+const THRESHOLD_BYTES = 5000;
+/** The size discrepancy as a percentage. */
+const THRESHOLD_PERCENT = 5;
+
+interface SizeCheckResult {
+  expected: number;
+  actual: number | undefined;
+  failing: boolean;
+  details:
+    | 'missing'
+    | {
+        raw: string;
+        percent: string;
+      };
+}
+
+export class SizeTracker {
+  constructor(private readonly testPackage: string) {}
+
+  /**
+   * Runs the size tracking scripting.
+   *
+   * Builds the integration test application and then checks if the size of the generated files varies too
+   * far from our known file sizes.
+   */
+  async run(testWorkingDir: string, commandEnv: NodeJS.ProcessEnv): Promise<void> {
+    const sizeJsonFilePath = path.join(testWorkingDir, 'size.json');
+    // If the integration test provides a size.json file we use it as a size tracking marker.
+    if (!existsSync(sizeJsonFilePath)) {
+      debug(`Skipping size tracking as no size.json file was found at ${sizeJsonFilePath}`);
+      return;
+    }
+    const success = await runCommandInChildProcess('yarn', ['build'], testWorkingDir, commandEnv);
+    if (!success) {
+      throw Error('Failed to build for size tracking.');
+    }
+
+    const sizes: {[key: string]: SizeCheckResult} = {};
+
+    const expectedSizes = JSON.parse(await fs.readFile(sizeJsonFilePath, 'utf-8')) as {
+      [key: string]: number;
+    };
+
+    for (let [filename, expectedSize] of Object.entries(expectedSizes)) {
+      const generedFilePath = path.join(testWorkingDir, filename);
+      if (!existsSync(generedFilePath)) {
+        sizes[filename] = {
+          actual: undefined,
+          failing: true,
+          expected: expectedSize,
+          details: 'missing',
+        };
+      } else {
+        const {size: actualSize} = await fs.stat(generedFilePath);
+        const absoluteSizeDiff = Math.abs(actualSize - expectedSize);
+        const percentSizeDiff = (absoluteSizeDiff / expectedSize) * 100;
+        const direction = actualSize === expectedSize ? '' : actualSize > expectedSize ? '+' : '-';
+        sizes[filename] = {
+          actual: actualSize,
+          expected: expectedSize,
+          failing: absoluteSizeDiff > THRESHOLD_BYTES || percentSizeDiff > THRESHOLD_PERCENT,
+          details: {
+            raw: `${direction}${absoluteSizeDiff.toFixed(0)}`,
+            percent: `${direction}${Math.round(percentSizeDiff * 1000) / 1000}`,
+          },
+        };
+      }
+    }
+
+    console.info();
+    console.info(Array(80).fill('=').join(''));
+    console.info(
+      `${Array(28).fill('=').join('')} SIZE TRACKING RESULTS ${Array(29).fill('=').join('')}`,
+    );
+    console.info(Array(80).fill('=').join(''));
+    let failed = false;
+    for (let [filename, {actual, expected, failing, details}] of Object.entries(sizes)) {
+      failed = failed || failing;
+      const bullet = failing ? red('✘') : green('✔');
+      console.info(`  ${bullet} ${filename}`);
+      if (details === 'missing') {
+        console.info(
+          `      File not found in generated integration test application, either ensure the file is created or remove it from the size tracking json file.`,
+        );
+      } else {
+        console.info(
+          `      Actual Size: ${actual} | Expected Size: ${expected} | ${details.raw} bytes (${details.percent}%)`,
+        );
+      }
+    }
+    console.info();
+    if (failed) {
+      const originalSizeJsonFilePath = path.join(this.testPackage, 'size.json');
+      console.info(
+        `If this is a desired change, please update the size limits in: ${originalSizeJsonFilePath}`,
+      );
+      process.exitCode = 1;
+    } else {
+      console.info(
+        `Payload size check passed. All diffs are less than ${THRESHOLD_PERCENT}% or ${THRESHOLD_BYTES} bytes.`,
+      );
+    }
+    console.info(Array(80).fill('=').join(''));
+    console.info();
+  }
+}
diff --git a/bazel/package.json b/bazel/package.json
index 312630df6..7182f1bc7 100644
--- a/bazel/package.json
+++ b/bazel/package.json
@@ -9,6 +9,7 @@
     "@types/wait-on": "^5.3.4",
     "@types/yargs": "17.0.33",
     "browser-sync": "3.0.4",
+    "chalk": "5.4.1",
     "piscina": "^5.0.0",
     "send": "1.2.0",
     "true-case-path": "2.2.1",
diff --git a/bazel/pnpm-lock.yaml b/bazel/pnpm-lock.yaml
index ab2b50353..dfffa41d5 100644
--- a/bazel/pnpm-lock.yaml
+++ b/bazel/pnpm-lock.yaml
@@ -32,6 +32,9 @@ importers:
       browser-sync:
         specifier: 3.0.4
         version: 3.0.4
+      chalk:
+        specifier: 5.4.1
+        version: 5.4.1
       piscina:
         specifier: ^5.0.0
         version: 5.1.2
@@ -442,6 +445,10 @@ packages:
     resolution: {integrity: sha512-oKnbhFyRIXpUuez8iBMmyEa4nbj4IOQyuhc/wy9kY7/WVPcwIO9VA668Pu8RkO7+0G76SLROeyw9CpQ061i4mA==}
     engines: {node: '>=10'}
 
+  chalk@5.4.1:
+    resolution: {integrity: sha512-zgVZuo2WcZgfUEmsn6eO3kINexW8RAE4maiQ8QNs8CtpPCSyMiYsULR3HQYkm3w8FIA3SberyMJMSldGsW+U3w==}
+    engines: {node: ^12.17.0 || ^14.13 || >=16.0.0}
+
   chokidar@3.6.0:
     resolution: {integrity: sha512-7VT13fmjotKpGipCW9JEQAusEPE+Ei8nl6/g4FBAmIm0GOOLMua9NDDo/DWp0ZAxCr3cPq5ZpBqmPAQgDda2Pw==}
     engines: {node: '>= 8.10.0'}
@@ -1962,6 +1969,8 @@ snapshots:
       ansi-styles: 4.3.0
       supports-color: 7.2.0
 
+  chalk@5.4.1: {}
+
   chokidar@3.6.0:
     dependencies:
       anymatch: 3.1.3