diff --git a/packages/sdk/browser/__tests__/BrowserClient.test.ts b/packages/sdk/browser/__tests__/BrowserClient.test.ts
new file mode 100644
index 0000000000..b32bbac169
--- /dev/null
+++ b/packages/sdk/browser/__tests__/BrowserClient.test.ts
@@ -0,0 +1,272 @@
+import { jest } from '@jest/globals';
+
+import {
+  AutoEnvAttributes,
+  EventSourceCapabilities,
+  EventSourceInitDict,
+  Hasher,
+  LDLogger,
+  PlatformData,
+  Requests,
+  SdkData,
+} from '@launchdarkly/js-client-sdk-common';
+
+import { BrowserClient } from '../src/BrowserClient';
+
+function mockResponse(value: string, statusCode: number) {
+  const response: Response = {
+    headers: {
+      // @ts-ignore
+      get: jest.fn(),
+      // @ts-ignore
+      keys: jest.fn(),
+      // @ts-ignore
+      values: jest.fn(),
+      // @ts-ignore
+      entries: jest.fn(),
+      // @ts-ignore
+      has: jest.fn(),
+    },
+    status: statusCode,
+    text: () => Promise.resolve(value),
+    json: () => Promise.resolve(JSON.parse(value)),
+  };
+  return Promise.resolve(response);
+}
+
+function mockFetch(value: string, statusCode: number = 200) {
+  const f = jest.fn();
+  // @ts-ignore
+  f.mockResolvedValue(mockResponse(value, statusCode));
+  return f;
+}
+
+function makeRequests(): Requests {
+  return {
+    // @ts-ignore
+    fetch: jest.fn((url: string, _options: any) => {
+      if (url.includes('/sdk/goals/')) {
+        return mockFetch(
+          JSON.stringify([
+            {
+              key: 'pageview',
+              kind: 'pageview',
+              urls: [{ kind: 'exact', url: 'http://browserclientintegration.com' }],
+            },
+            {
+              key: 'click',
+              kind: 'click',
+              selector: '.button',
+              urls: [{ kind: 'exact', url: 'http://browserclientintegration.com' }],
+            },
+          ]),
+          200,
+        )();
+      }
+      return mockFetch('{ "flagA": true }', 200)();
+    }),
+    // @ts-ignore
+    createEventSource(_url: string, _eventSourceInitDict: EventSourceInitDict): EventSource {
+      throw new Error('Function not implemented.');
+    },
+    getEventSourceCapabilities(): EventSourceCapabilities {
+      return {
+        readTimeout: false,
+        headers: false,
+        customMethod: false,
+      };
+    },
+  };
+}
+
+class MockHasher implements Hasher {
+  update(_data: string): Hasher {
+    return this;
+  }
+  digest?(_encoding: string): string {
+    return 'hashed';
+  }
+  async asyncDigest?(_encoding: string): Promise<string> {
+    return 'hashed';
+  }
+}
+
+describe('given a mock platform for a BrowserClient', () => {
+  const logger: LDLogger = {
+    debug: jest.fn(),
+    info: jest.fn(),
+    warn: jest.fn(),
+    error: jest.fn(),
+  };
+
+  let platform: any;
+  beforeEach(() => {
+    Object.defineProperty(window, 'location', {
+      value: { href: 'http://browserclientintegration.com' },
+      writable: true,
+    });
+    jest.useFakeTimers().setSystemTime(new Date('2024-09-19'));
+    platform = {
+      requests: makeRequests(),
+      info: {
+        platformData(): PlatformData {
+          return {
+            name: 'node',
+          };
+        },
+        sdkData(): SdkData {
+          return {
+            name: 'browser-sdk',
+            version: '1.0.0',
+          };
+        },
+      },
+      crypto: {
+        createHash: () => new MockHasher(),
+        randomUUID: () => '123',
+      },
+      storage: {
+        get: async (_key: string) => null,
+        set: async (_key: string, _value: string) => {},
+        clear: async (_key: string) => {},
+      },
+      encoding: {
+        btoa: (str: string) => str,
+      },
+    };
+  });
+
+  it('includes urls in custom events', async () => {
+    const client = new BrowserClient(
+      'client-side-id',
+      AutoEnvAttributes.Disabled,
+      {
+        initialConnectionMode: 'polling',
+        logger,
+        diagnosticOptOut: true,
+      },
+      platform,
+    );
+    await client.identify({ key: 'user-key', kind: 'user' });
+    await client.flush();
+    client.track('user-key', undefined, 1);
+    await client.flush();
+
+    expect(JSON.parse(platform.requests.fetch.mock.calls[3][1].body)[0]).toMatchObject({
+      kind: 'custom',
+      creationDate: 1726704000000,
+      key: 'user-key',
+      contextKeys: {
+        user: 'user-key',
+      },
+      metricValue: 1,
+      url: 'http://browserclientintegration.com',
+    });
+  });
+
+  it('can filter URLs in custom events', async () => {
+    const client = new BrowserClient(
+      'client-side-id',
+      AutoEnvAttributes.Disabled,
+      {
+        initialConnectionMode: 'polling',
+        logger,
+        diagnosticOptOut: true,
+        eventUrlTransformer: (url: string) =>
+          url.replace('http://browserclientintegration.com', 'http://filtered.org'),
+      },
+      platform,
+    );
+    await client.identify({ key: 'user-key', kind: 'user' });
+    await client.flush();
+    client.track('user-key', undefined, 1);
+    await client.flush();
+
+    const events = JSON.parse(platform.requests.fetch.mock.calls[3][1].body);
+    const customEvent = events.find((e: any) => e.kind === 'custom');
+
+    expect(customEvent).toMatchObject({
+      kind: 'custom',
+      creationDate: 1726704000000,
+      key: 'user-key',
+      contextKeys: {
+        user: 'user-key',
+      },
+      metricValue: 1,
+      url: 'http://filtered.org',
+    });
+  });
+
+  it('can filter URLs in click events', async () => {
+    const client = new BrowserClient(
+      'client-side-id',
+      AutoEnvAttributes.Disabled,
+      {
+        initialConnectionMode: 'polling',
+        logger,
+        diagnosticOptOut: true,
+        eventUrlTransformer: (url: string) =>
+          url.replace('http://browserclientintegration.com', 'http://filtered.org'),
+      },
+      platform,
+    );
+    await client.identify({ key: 'user-key', kind: 'user' });
+    await client.flush();
+
+    // Simulate a click event
+    const button = document.createElement('button');
+    button.className = 'button';
+    document.body.appendChild(button);
+    button.click();
+
+    while (platform.requests.fetch.mock.calls.length < 4) {
+      // eslint-disable-next-line no-await-in-loop
+      await client.flush();
+      jest.runAllTicks();
+    }
+
+    const events = JSON.parse(platform.requests.fetch.mock.calls[3][1].body);
+    const clickEvent = events.find((e: any) => e.kind === 'click');
+    expect(clickEvent).toMatchObject({
+      kind: 'click',
+      creationDate: 1726704000000,
+      key: 'click',
+      contextKeys: {
+        user: 'user-key',
+      },
+      url: 'http://filtered.org',
+    });
+
+    document.body.removeChild(button);
+  });
+
+  it('can filter URLs in pageview events', async () => {
+    const client = new BrowserClient(
+      'client-side-id',
+      AutoEnvAttributes.Disabled,
+      {
+        initialConnectionMode: 'polling',
+        logger,
+        diagnosticOptOut: true,
+        eventUrlTransformer: (url: string) =>
+          url.replace('http://browserclientintegration.com', 'http://filtered.com'),
+      },
+      platform,
+    );
+
+    await client.identify({ key: 'user-key', kind: 'user' });
+    await client.flush();
+
+    const events = JSON.parse(platform.requests.fetch.mock.calls[2][1].body);
+    const pageviewEvent = events.find((e: any) => e.kind === 'pageview');
+    expect(pageviewEvent).toMatchObject({
+      kind: 'pageview',
+      creationDate: 1726704000000,
+      key: 'pageview',
+      contextKeys: {
+        user: 'user-key',
+      },
+      url: 'http://filtered.com',
+    });
+  });
+});
diff --git a/packages/sdk/browser/__tests__/goals/GoalManager.test.ts b/packages/sdk/browser/__tests__/goals/GoalManager.test.ts
index 819528aa69..acdd6e5b1f 100644
--- a/packages/sdk/browser/__tests__/goals/GoalManager.test.ts
+++ b/packages/sdk/browser/__tests__/goals/GoalManager.test.ts
@@ -47,6 +47,7 @@ describe('given a GoalManager with mocked dependencies', () => {
     } as any);
 
     await goalManager.initialize();
+    goalManager.startTracking();
 
     expect(mockRequests.fetch).toHaveBeenCalledWith('polling/sdk/goals/test-credential');
     expect(mockLocationWatcherFactory).toHaveBeenCalled();
@@ -58,6 +59,7 @@ describe('given a GoalManager with mocked dependencies', () => {
     mockRequests.fetch.mockRejectedValue(error);
 
     await goalManager.initialize();
+    goalManager.startTracking();
 
     expect(mockReportError).toHaveBeenCalledWith(expect.any(LDUnexpectedResponseError));
   });
@@ -91,6 +93,7 @@ describe('given a GoalManager with mocked dependencies', () => {
       json: () => Promise.resolve(mockGoals),
     } as any);
     await goalManager.initialize();
+    goalManager.startTracking();
 
     // Check that no goal was emitted on initial load
     expect(mockReportGoal).not.toHaveBeenCalled();
diff --git a/packages/sdk/browser/__tests__/goals/LocationWatcher.test.ts b/packages/sdk/browser/__tests__/goals/LocationWatcher.test.ts
index 561419d07a..d278402ac1 100644
--- a/packages/sdk/browser/__tests__/goals/LocationWatcher.test.ts
+++ b/packages/sdk/browser/__tests__/goals/LocationWatcher.test.ts
@@ -1,6 +1,9 @@
 import { jest } from '@jest/globals';
 
-import { DefaultLocationWatcher, LOCATION_WATCHER_INTERVAL } from '../../src/goals/LocationWatcher';
+import {
+  DefaultLocationWatcher,
+  LOCATION_WATCHER_INTERVAL_MS,
+} from '../../src/goals/LocationWatcher';
 
 let mockCallback: jest.Mock;
 
@@ -25,7 +28,7 @@ it('should call callback when URL changes', () => {
     value: { href: 'https://example.com/new-page' },
     writable: true,
   });
-  jest.advanceTimersByTime(LOCATION_WATCHER_INTERVAL);
+  jest.advanceTimersByTime(LOCATION_WATCHER_INTERVAL_MS);
 
   expect(mockCallback).toHaveBeenCalledTimes(1);
 
@@ -40,7 +43,7 @@ it('should not call callback when URL remains the same', () => {
 
   const watcher = new DefaultLocationWatcher(mockCallback);
 
-  jest.advanceTimersByTime(LOCATION_WATCHER_INTERVAL * 2);
+  jest.advanceTimersByTime(LOCATION_WATCHER_INTERVAL_MS * 2);
 
   expect(mockCallback).not.toHaveBeenCalled();
 
@@ -80,7 +83,7 @@ it('should stop watching when close is called', () => {
     value: { href: 'https://example.com/new-page' },
     writable: true,
   });
-  jest.advanceTimersByTime(LOCATION_WATCHER_INTERVAL);
+  jest.advanceTimersByTime(LOCATION_WATCHER_INTERVAL_MS);
   window.dispatchEvent(new Event('popstate'));
 
   expect(mockCallback).not.toHaveBeenCalled();
diff --git a/packages/sdk/browser/__tests__/options.test.ts b/packages/sdk/browser/__tests__/options.test.ts
index bbeee2fde8..cb1d84a67f 100644
--- a/packages/sdk/browser/__tests__/options.test.ts
+++ b/packages/sdk/browser/__tests__/options.test.ts
@@ -54,7 +54,7 @@ it('applies default options', () => {
   const opts = validateOptions({}, logger);
 
   expect(opts.fetchGoals).toBe(true);
-  expect(opts.eventUrlTransformer).toBeUndefined();
+  expect(opts.eventUrlTransformer).toBeDefined();
 
   expect(logger.debug).not.toHaveBeenCalled();
   expect(logger.info).not.toHaveBeenCalled();
diff --git a/packages/sdk/browser/jest.config.js b/packages/sdk/browser/jest.config.js
index 523d4a99d5..21105621a4 100644
--- a/packages/sdk/browser/jest.config.js
+++ b/packages/sdk/browser/jest.config.js
@@ -4,7 +4,7 @@ export default {
   preset: 'ts-jest/presets/default-esm',
   testEnvironment: 'jest-environment-jsdom',
   transform: {
-    '^.+\\.tsx?$': ['ts-jest', { useESM: true }],
+    '^.+\\.tsx?$': ['ts-jest', { useESM: true, tsconfig: 'tsconfig.json' }],
   },
   testPathIgnorePatterns: ['./dist'],
 };
diff --git a/packages/sdk/browser/package.json b/packages/sdk/browser/package.json
index 367528e2b4..c03638f278 100644
--- a/packages/sdk/browser/package.json
+++ b/packages/sdk/browser/package.json
@@ -30,7 +30,7 @@
     "build": "rollup -c rollup.config.js",
     "lint": "eslint . --ext .ts,.tsx",
     "prettier": "prettier --write '**/*.@(js|ts|tsx|json|css)' --ignore-path ../../../.prettierignore",
-    "test": "NODE_OPTIONS=--experimental-vm-modules npx jest",
+    "test": "NODE_OPTIONS=--experimental-vm-modules npx jest --runInBand",
     "coverage": "yarn test --coverage",
     "check": "yarn prettier && yarn lint && yarn build && yarn test"
   },
diff --git a/packages/sdk/browser/src/BrowserClient.ts b/packages/sdk/browser/src/BrowserClient.ts
index f248119012..a275fddccd 100644
--- a/packages/sdk/browser/src/BrowserClient.ts
+++ b/packages/sdk/browser/src/BrowserClient.ts
@@ -5,8 +5,10 @@ import {
   LDClient as CommonClient,
   DataSourcePaths,
   Encoding,
+  internal,
   LDClientImpl,
   LDContext,
+  Platform,
 } from '@launchdarkly/js-client-sdk-common';
 
 import GoalManager from './goals/GoalManager';
@@ -25,6 +27,7 @@ export class BrowserClient extends LDClientImpl {
     private readonly clientSideId: string,
     autoEnvAttributes: AutoEnvAttributes,
     options: BrowserOptions = {},
+    overridePlatform?: Platform,
   ) {
     const { logger: customLogger, debug } = options;
     const logger =
@@ -38,14 +41,24 @@ export class BrowserClient extends LDClientImpl {
     // TODO: Use the already-configured baseUri from the SDK config. SDK-560
     const baseUrl = options.baseUri ?? 'https://clientsdk.launchdarkly.com';
 
-    const platform = new BrowserPlatform(options);
+    const platform = overridePlatform ?? new BrowserPlatform(logger);
     const ValidatedBrowserOptions = validateOptions(options, logger);
+    const { eventUrlTransformer } = ValidatedBrowserOptions;
     super(clientSideId, autoEnvAttributes, platform, filterToBaseOptions(options), {
       analyticsEventPath: `/events/bulk/${clientSideId}`,
       diagnosticEventPath: `/events/diagnostic/${clientSideId}`,
       includeAuthorizationHeader: false,
       highTimeoutThreshold: 5,
       userAgentHeaderName: 'x-launchdarkly-user-agent',
+      trackEventModifier: (event: internal.InputCustomEvent) =>
+        new internal.InputCustomEvent(
+          event.context,
+          event.key,
+          event.data,
+          event.metricValue,
+          event.samplingRatio,
+          eventUrlTransformer(window.location.href),
+        ),
     });
 
     if (ValidatedBrowserOptions.fetchGoals) {
@@ -62,10 +75,11 @@ export class BrowserClient extends LDClientImpl {
           if (!context) {
             return;
           }
+          const transformedUrl = eventUrlTransformer(url);
           if (isClick(goal)) {
             this.sendEvent({
               kind: 'click',
-              url,
+              url: transformedUrl,
               samplingRatio: 1,
               key: goal.key,
               creationDate: Date.now(),
@@ -75,7 +89,7 @@ export class BrowserClient extends LDClientImpl {
           } else {
             this.sendEvent({
               kind: 'pageview',
-              url,
+              url: transformedUrl,
               samplingRatio: 1,
               key: goal.key,
               creationDate: Date.now(),
@@ -120,4 +134,9 @@ export class BrowserClient extends LDClientImpl {
       },
     };
   }
+
+  override async identify(context: LDContext): Promise<void> {
+    await super.identify(context);
+    this.goalManager?.startTracking();
+  }
 }
diff --git a/packages/sdk/browser/src/goals/GoalManager.ts b/packages/sdk/browser/src/goals/GoalManager.ts
index eecd21f920..50932dd0cd 100644
--- a/packages/sdk/browser/src/goals/GoalManager.ts
+++ b/packages/sdk/browser/src/goals/GoalManager.ts
@@ -9,6 +9,7 @@ export default class GoalManager {
   private url: string;
   private watcher?: LocationWatcher;
   private tracker?: GoalTracker;
+  private isTracking = false;
 
   constructor(
     credential: string,
@@ -29,10 +30,20 @@ export default class GoalManager {
 
   public async initialize(): Promise<void> {
     await this.fetchGoals();
+    // If tracking has been started before goal fetching completes, we need to
+    // create the tracker so it can start watching for events.
+    this.createTracker();
+  }
+
+  public startTracking() {
+    this.isTracking = true;
     this.createTracker();
   }
 
   private createTracker() {
+    if (!this.isTracking) {
+      return;
+    }
     this.tracker?.close();
     if (this.goals && this.goals.length) {
       this.tracker = new GoalTracker(this.goals, (goal) => {
diff --git a/packages/sdk/browser/src/goals/LocationWatcher.ts b/packages/sdk/browser/src/goals/LocationWatcher.ts
index 4343f644e3..7b6c5e3de1 100644
--- a/packages/sdk/browser/src/goals/LocationWatcher.ts
+++ b/packages/sdk/browser/src/goals/LocationWatcher.ts
@@ -1,4 +1,4 @@
-export const LOCATION_WATCHER_INTERVAL = 300;
+export const LOCATION_WATCHER_INTERVAL_MS = 300;
 
 // Using any for the timer handle because the type is not the same for all
 // platforms and we only need to use it opaquely.
@@ -39,7 +39,7 @@ export class DefaultLocationWatcher {
      * Details on when popstate is called:
      * https://developer.mozilla.org/en-US/docs/Web/API/Window/popstate_event#when_popstate_is_sent
      */
-    this.watcherHandle = setInterval(checkUrl, LOCATION_WATCHER_INTERVAL);
+    this.watcherHandle = setInterval(checkUrl, LOCATION_WATCHER_INTERVAL_MS);
 
     window.addEventListener('popstate', checkUrl);
 
diff --git a/packages/sdk/browser/src/index.ts b/packages/sdk/browser/src/index.ts
index 26015a6744..26f5e703b9 100644
--- a/packages/sdk/browser/src/index.ts
+++ b/packages/sdk/browser/src/index.ts
@@ -18,10 +18,8 @@ import {
 import { BrowserClient, LDClient } from './BrowserClient';
 import { BrowserOptions as LDOptions } from './options';
 
-// TODO: Export and use browser specific options.
 export {
   LDClient,
-  AutoEnvAttributes,
   LDFlagSet,
   LDContext,
   LDContextCommon,
@@ -36,10 +34,7 @@ export {
   LDEvaluationReason,
 };
 
-export function init(
-  clientSideId: string,
-  autoEnvAttributes: AutoEnvAttributes,
-  options?: LDOptions,
-): LDClient {
-  return new BrowserClient(clientSideId, autoEnvAttributes, options);
+export function init(clientSideId: string, options?: LDOptions): LDClient {
+  // AutoEnvAttributes are not supported yet in the browser SDK.
+  return new BrowserClient(clientSideId, AutoEnvAttributes.Disabled, options);
 }
diff --git a/packages/sdk/browser/src/options.ts b/packages/sdk/browser/src/options.ts
index c0d62c549c..d08eb53b2a 100644
--- a/packages/sdk/browser/src/options.ts
+++ b/packages/sdk/browser/src/options.ts
@@ -28,12 +28,12 @@ export interface BrowserOptions extends LDOptionsBase {
 
 export interface ValidatedOptions {
   fetchGoals: boolean;
-  eventUrlTransformer?: (url: string) => string;
+  eventUrlTransformer: (url: string) => string;
 }
 
 const optDefaults = {
   fetchGoals: true,
-  eventUrlTransformer: undefined,
+  eventUrlTransformer: (url: string) => url,
 };
 
 const validators: { [Property in keyof BrowserOptions]: TypeValidator | undefined } = {
diff --git a/packages/sdk/browser/src/platform/BrowserInfo.ts b/packages/sdk/browser/src/platform/BrowserInfo.ts
index 637ebad50b..3a2c064fba 100644
--- a/packages/sdk/browser/src/platform/BrowserInfo.ts
+++ b/packages/sdk/browser/src/platform/BrowserInfo.ts
@@ -1,7 +1,5 @@
 import { Info, PlatformData, SdkData } from '@launchdarkly/js-client-sdk-common';
 
-import { name, version } from '../../package.json';
-
 export default class BrowserInfo implements Info {
   platformData(): PlatformData {
     return {
@@ -10,8 +8,8 @@ export default class BrowserInfo implements Info {
   }
   sdkData(): SdkData {
     return {
-      name,
-      version,
+      name: '@launchdarkly/js-client-sdk',
+      version: '0.0.0', // x-release-please-version
       userAgentBase: 'JSClient',
     };
   }
diff --git a/packages/sdk/browser/src/platform/BrowserPlatform.ts b/packages/sdk/browser/src/platform/BrowserPlatform.ts
index 34dfccaefa..33b5b10248 100644
--- a/packages/sdk/browser/src/platform/BrowserPlatform.ts
+++ b/packages/sdk/browser/src/platform/BrowserPlatform.ts
@@ -2,7 +2,7 @@ import {
   Crypto,
   Encoding,
   Info,
-  LDOptions,
+  LDLogger,
   Platform,
   Requests,
   Storage,
@@ -22,9 +22,9 @@ export default class BrowserPlatform implements Platform {
   requests: Requests = new BrowserRequests();
   storage?: Storage;
 
-  constructor(options: LDOptions) {
+  constructor(logger: LDLogger) {
     if (isLocalStorageSupported()) {
-      this.storage = new LocalStorage(options.logger);
+      this.storage = new LocalStorage(logger);
     }
   }
 }
diff --git a/packages/sdk/browser/tsconfig.json b/packages/sdk/browser/tsconfig.json
index 0a219e1516..2f2d034948 100644
--- a/packages/sdk/browser/tsconfig.json
+++ b/packages/sdk/browser/tsconfig.json
@@ -30,7 +30,7 @@
     "node_modules",
     "contract-tests",
     "babel.config.js",
-    "jest.config.ts",
+    "jest.config.js",
     "jestSetupFile.ts",
     "**/*.test.ts*"
   ]
diff --git a/packages/sdk/browser/tsconfig.test.json b/packages/sdk/browser/tsconfig.test.json
deleted file mode 100644
index 2c617dcaa7..0000000000
--- a/packages/sdk/browser/tsconfig.test.json
+++ /dev/null
@@ -1,14 +0,0 @@
-{
-  "compilerOptions": {
-    "esModuleInterop": true,
-    "jsx": "react-jsx",
-    "lib": ["es6", "dom"],
-    "module": "ES6",
-    "moduleResolution": "node",
-    "resolveJsonModule": true,
-    "rootDir": ".",
-    "strict": true,
-    "types": ["jest", "node"]
-  },
-  "exclude": ["dist", "node_modules", "__tests__", "example"]
-}
diff --git a/packages/shared/common/src/internal/events/EventProcessor.ts b/packages/shared/common/src/internal/events/EventProcessor.ts
index ef4a6e490a..4e6acd128e 100644
--- a/packages/shared/common/src/internal/events/EventProcessor.ts
+++ b/packages/shared/common/src/internal/events/EventProcessor.ts
@@ -36,6 +36,7 @@ interface CustomOutputEvent {
   data?: any;
   metricValue?: number;
   samplingRatio?: number;
+  url?: string;
 }
 
 interface FeatureOutputEvent {
@@ -344,6 +345,10 @@ export default class EventProcessor implements LDEventProcessor {
           out.metricValue = event.metricValue;
         }
 
+        if (event.url !== undefined) {
+          out.url = event.url;
+        }
+
         return out;
       }
       case 'click': {
diff --git a/packages/shared/common/src/internal/events/InputCustomEvent.ts b/packages/shared/common/src/internal/events/InputCustomEvent.ts
index 1c0c4a2b39..a8e29364f6 100644
--- a/packages/shared/common/src/internal/events/InputCustomEvent.ts
+++ b/packages/shared/common/src/internal/events/InputCustomEvent.ts
@@ -13,6 +13,8 @@ export default class InputCustomEvent {
     // Currently custom events are not sampled, but this is here to make the handling
     // code more uniform.
     public readonly samplingRatio: number = 1,
+    // Browser SDKs can include a URL for custom events.
+    public readonly url?: string,
   ) {
     this.creationDate = Date.now();
     this.context = context;
diff --git a/packages/shared/sdk-client/src/LDClientImpl.ts b/packages/shared/sdk-client/src/LDClientImpl.ts
index 1392db206a..8ce5538590 100644
--- a/packages/shared/sdk-client/src/LDClientImpl.ts
+++ b/packages/shared/sdk-client/src/LDClientImpl.ts
@@ -23,6 +23,7 @@ import { ConnectionMode, LDClient, type LDOptions } from './api';
 import { LDEvaluationDetail, LDEvaluationDetailTyped } from './api/LDEvaluationDetail';
 import { LDIdentifyOptions } from './api/LDIdentifyOptions';
 import Configuration from './configuration';
+import { LDClientInternalOptions } from './configuration/Configuration';
 import { addAutoEnv } from './context/addAutoEnv';
 import { ensureKey } from './context/ensureKey';
 import createDiagnosticsManager from './diagnostics/createDiagnosticsManager';
@@ -72,7 +73,7 @@ export default class LDClientImpl implements LDClient {
     public readonly autoEnvAttributes: AutoEnvAttributes,
     public readonly platform: Platform,
     options: LDOptions,
-    internalOptions?: internal.LDInternalOptions,
+    internalOptions?: LDClientInternalOptions,
   ) {
     if (!sdkKey) {
       throw new Error('You must configure the client with a client-side SDK key');
@@ -502,7 +503,9 @@ export default class LDClientImpl implements LDClient {
     }
 
     this.eventProcessor?.sendEvent(
-      this.eventFactoryDefault.customEvent(key, this.checkedContext!, data, metricValue),
+      this.config.trackEventModifier(
+        this.eventFactoryDefault.customEvent(key, this.checkedContext!, data, metricValue),
+      ),
     );
   }
 
diff --git a/packages/shared/sdk-client/src/configuration/Configuration.ts b/packages/shared/sdk-client/src/configuration/Configuration.ts
index e68dd9f746..64bb9867e2 100644
--- a/packages/shared/sdk-client/src/configuration/Configuration.ts
+++ b/packages/shared/sdk-client/src/configuration/Configuration.ts
@@ -14,6 +14,10 @@ import validators from './validators';
 
 const DEFAULT_POLLING_INTERVAL: number = 60 * 5;
 
+export interface LDClientInternalOptions extends internal.LDInternalOptions {
+  trackEventModifier?: (event: internal.InputCustomEvent) => internal.InputCustomEvent;
+}
+
 export default class Configuration {
   public static DEFAULT_POLLING = 'https://clientsdk.launchdarkly.com';
   public static DEFAULT_STREAM = 'https://clientstream.launchdarkly.com';
@@ -66,10 +70,14 @@ export default class Configuration {
 
   public readonly userAgentHeaderName: 'user-agent' | 'x-launchdarkly-user-agent';
 
+  public readonly trackEventModifier: (
+    event: internal.InputCustomEvent,
+  ) => internal.InputCustomEvent;
+
   // Allow indexing Configuration by a string
   [index: string]: any;
 
-  constructor(pristineOptions: LDOptions = {}, internalOptions: internal.LDInternalOptions = {}) {
+  constructor(pristineOptions: LDOptions = {}, internalOptions: LDClientInternalOptions = {}) {
     const errors = this.validateTypesAndNames(pristineOptions);
     errors.forEach((e: string) => this.logger.warn(e));
 
@@ -86,6 +94,7 @@ export default class Configuration {
 
     this.tags = new ApplicationTags({ application: this.applicationInfo, logger: this.logger });
     this.userAgentHeaderName = internalOptions.userAgentHeaderName ?? 'user-agent';
+    this.trackEventModifier = internalOptions.trackEventModifier ?? ((event) => event);
   }
 
   validateTypesAndNames(pristineOptions: LDOptions): string[] {
diff --git a/packages/shared/sdk-client/src/index.ts b/packages/shared/sdk-client/src/index.ts
index a4186185d4..d5b3e293d4 100644
--- a/packages/shared/sdk-client/src/index.ts
+++ b/packages/shared/sdk-client/src/index.ts
@@ -1,3 +1,4 @@
+import { LDClientInternalOptions } from './configuration/Configuration';
 import LDClientImpl from './LDClientImpl';
 
 export * from '@launchdarkly/js-sdk-common';
@@ -18,4 +19,4 @@ export type {
 
 export { DataSourcePaths } from './streaming';
 
-export { LDClientImpl };
+export { LDClientImpl, LDClientInternalOptions };