diff --git a/packages/telemetry/browser-telemetry/__tests__/BrowserTelemetryImpl.test.ts b/packages/telemetry/browser-telemetry/__tests__/BrowserTelemetryImpl.test.ts
new file mode 100644
index 000000000..8233f46fb
--- /dev/null
+++ b/packages/telemetry/browser-telemetry/__tests__/BrowserTelemetryImpl.test.ts
@@ -0,0 +1,210 @@
+import { LDClientTracking } from '../src/api/client/LDClientTracking';
+import BrowserTelemetryImpl from '../src/BrowserTelemetryImpl';
+import { ParsedOptions } from '../src/options';
+
+const mockClient: jest.Mocked<LDClientTracking> = {
+  track: jest.fn(),
+};
+
+afterEach(() => {
+  jest.resetAllMocks();
+});
+
+const defaultOptions: ParsedOptions = {
+  maxPendingEvents: 100,
+  breadcrumbs: {
+    maxBreadcrumbs: 50,
+    click: true,
+    keyboardInput: true,
+    http: {
+      instrumentFetch: true,
+      instrumentXhr: true,
+    },
+    evaluations: true,
+    flagChange: true,
+  },
+  stack: {
+    source: {
+      beforeLines: 5,
+      afterLines: 5,
+      maxLineLength: 120,
+    },
+  },
+  collectors: [],
+};
+
+it('sends buffered events when client is registered', () => {
+  const telemetry = new BrowserTelemetryImpl(defaultOptions);
+  const error = new Error('Test error');
+
+  telemetry.captureError(error);
+  telemetry.register(mockClient);
+
+  expect(mockClient.track).toHaveBeenCalledWith(
+    '$ld:telemetry:error',
+    expect.objectContaining({
+      type: 'Error',
+      message: 'Test error',
+      stack: { frames: expect.any(Array) },
+      breadcrumbs: [],
+      sessionId: expect.any(String),
+    }),
+  );
+});
+
+it('limits pending events to maxPendingEvents', () => {
+  const options: ParsedOptions = {
+    ...defaultOptions,
+    maxPendingEvents: 2,
+  };
+  const telemetry = new BrowserTelemetryImpl(options);
+
+  telemetry.captureError(new Error('Error 1'));
+  telemetry.captureError(new Error('Error 2'));
+  telemetry.captureError(new Error('Error 3'));
+
+  telemetry.register(mockClient);
+
+  // Should only see the last 2 errors tracked
+  expect(mockClient.track).toHaveBeenCalledTimes(2);
+  expect(mockClient.track).toHaveBeenCalledWith(
+    '$ld:telemetry:error',
+    expect.objectContaining({
+      message: 'Error 2',
+    }),
+  );
+  expect(mockClient.track).toHaveBeenCalledWith(
+    '$ld:telemetry:error',
+    expect.objectContaining({
+      message: 'Error 3',
+    }),
+  );
+});
+
+it('manages breadcrumbs with size limit', () => {
+  const options: ParsedOptions = {
+    ...defaultOptions,
+    breadcrumbs: { ...defaultOptions.breadcrumbs, maxBreadcrumbs: 2 },
+  };
+  const telemetry = new BrowserTelemetryImpl(options);
+
+  telemetry.addBreadcrumb({
+    type: 'custom',
+    data: { id: 1 },
+    timestamp: Date.now(),
+    class: 'custom',
+    level: 'info',
+  });
+
+  telemetry.addBreadcrumb({
+    type: 'custom',
+    data: { id: 2 },
+    timestamp: Date.now(),
+    class: 'custom',
+    level: 'info',
+  });
+
+  telemetry.addBreadcrumb({
+    type: 'custom',
+    data: { id: 3 },
+    timestamp: Date.now(),
+    class: 'custom',
+    level: 'info',
+  });
+
+  const error = new Error('Test error');
+  telemetry.captureError(error);
+  telemetry.register(mockClient);
+
+  expect(mockClient.track).toHaveBeenCalledWith(
+    '$ld:telemetry:error',
+    expect.objectContaining({
+      breadcrumbs: expect.arrayContaining([
+        expect.objectContaining({ data: { id: 2 } }),
+        expect.objectContaining({ data: { id: 3 } }),
+      ]),
+    }),
+  );
+});
+
+it('handles null/undefined errors gracefully', () => {
+  const telemetry = new BrowserTelemetryImpl(defaultOptions);
+
+  // @ts-ignore - Testing runtime behavior with invalid input
+  telemetry.captureError(undefined);
+  telemetry.register(mockClient);
+
+  expect(mockClient.track).toHaveBeenCalledWith(
+    '$ld:telemetry:error',
+    expect.objectContaining({
+      type: 'generic',
+      message: 'exception was null or undefined',
+      breadcrumbs: [],
+    }),
+  );
+});
+
+it('captures error events', () => {
+  const telemetry = new BrowserTelemetryImpl(defaultOptions);
+  const error = new Error('Test error');
+  const errorEvent = new ErrorEvent('error', { error });
+
+  telemetry.captureErrorEvent(errorEvent);
+  telemetry.register(mockClient);
+
+  expect(mockClient.track).toHaveBeenCalledWith(
+    '$ld:telemetry:error',
+    expect.objectContaining({
+      type: 'Error',
+      message: 'Test error',
+      breadcrumbs: [],
+    }),
+  );
+});
+
+it('handles flag evaluation breadcrumbs', () => {
+  const telemetry = new BrowserTelemetryImpl(defaultOptions);
+
+  telemetry.handleFlagUsed('test-flag', {
+    value: true,
+    variationIndex: 1,
+    reason: { kind: 'OFF' },
+  });
+
+  const error = new Error('Test error');
+  telemetry.captureError(error);
+  telemetry.register(mockClient);
+
+  expect(mockClient.track).toHaveBeenCalledWith(
+    '$ld:telemetry:error',
+    expect.objectContaining({
+      breadcrumbs: expect.arrayContaining([
+        expect.objectContaining({
+          type: 'flag-evaluated',
+          data: {
+            key: 'test-flag',
+            value: true,
+          },
+          class: 'feature-management',
+        }),
+      ]),
+    }),
+  );
+});
+
+it('unregisters collectors on close', () => {
+  const mockCollector = {
+    register: jest.fn(),
+    unregister: jest.fn(),
+  };
+
+  const options: ParsedOptions = {
+    ...defaultOptions,
+    collectors: [mockCollector],
+  };
+
+  const telemetry = new BrowserTelemetryImpl(options);
+  telemetry.close();
+
+  expect(mockCollector.unregister).toHaveBeenCalled();
+});
diff --git a/packages/telemetry/browser-telemetry/package.json b/packages/telemetry/browser-telemetry/package.json
index cb5963475..49c2a1902 100644
--- a/packages/telemetry/browser-telemetry/package.json
+++ b/packages/telemetry/browser-telemetry/package.json
@@ -47,10 +47,8 @@
     "rrweb": "2.0.0-alpha.4",
     "tracekit": "^0.4.6"
   },
-  "peerDependencies": {
-    "launchdarkly-js-client-sdk": "^3.4.0"
-  },
   "devDependencies": {
+    "@launchdarkly/js-client-sdk": "0.3.2",
     "@jest/globals": "^29.7.0",
     "@trivago/prettier-plugin-sort-imports": "^4.1.1",
     "@types/css-font-loading-module": "^0.0.13",
diff --git a/packages/telemetry/browser-telemetry/src/BrowserTelemetryImpl.ts b/packages/telemetry/browser-telemetry/src/BrowserTelemetryImpl.ts
new file mode 100644
index 000000000..41ce9a351
--- /dev/null
+++ b/packages/telemetry/browser-telemetry/src/BrowserTelemetryImpl.ts
@@ -0,0 +1,243 @@
+import * as TraceKit from 'tracekit';
+
+/**
+ * A limited selection of type information is provided by the browser client SDK.
+ * This is only a type dependency and these types should be compatible between
+ * SDKs.
+ */
+import type { LDContext, LDEvaluationDetail, LDInspection } from '@launchdarkly/js-client-sdk';
+
+import { LDClientTracking } from './api';
+import { Breadcrumb, FeatureManagementBreadcrumb } from './api/Breadcrumb';
+import { BrowserTelemetry } from './api/BrowserTelemetry';
+import { Collector } from './api/Collector';
+import { ErrorData } from './api/ErrorData';
+import { EventData } from './api/EventData';
+import ClickCollector from './collectors/dom/ClickCollector';
+import KeypressCollector from './collectors/dom/KeypressCollector';
+import ErrorCollector from './collectors/error';
+import FetchCollector from './collectors/http/fetch';
+import XhrCollector from './collectors/http/xhr';
+import defaultUrlFilter from './filters/defaultUrlFilter';
+import makeInspectors from './inspectors';
+import { ParsedOptions, ParsedStackOptions } from './options';
+import randomUuidV4 from './randomUuidV4';
+import parse from './stack/StackParser';
+
+// TODO: Use a ring buffer for the breadcrumbs/pending events instead of shifting. (SDK-914)
+
+const CUSTOM_KEY_PREFIX = '$ld:telemetry';
+const ERROR_KEY = `${CUSTOM_KEY_PREFIX}:error`;
+const SESSION_CAPTURE_KEY = `${CUSTOM_KEY_PREFIX}:sessionCapture`;
+const GENERIC_EXCEPTION = 'generic';
+const NULL_EXCEPTION_MESSAGE = 'exception was null or undefined';
+const MISSING_MESSAGE = 'exception had no message';
+
+/**
+ * Given a flag value ensure it is safe for analytics.
+ *
+ * If the parameter is not safe, then return undefined.
+ *
+ * TODO: Add limited JSON support. (SDK-916)
+ * @param u The value to check.
+ * @returns Either the value or undefined.
+ */
+function safeValue(u: unknown): string | boolean | number | undefined {
+  switch (typeof u) {
+    case 'string':
+    case 'boolean':
+    case 'number':
+      return u;
+    default:
+      return undefined;
+  }
+}
+
+function configureTraceKit(options: ParsedStackOptions) {
+  // Include before + after + source line.
+  // TraceKit only takes a total context size, so we have to over capture and then reduce the lines.
+  // So, for instance if before is 3 and after is 4 we need to capture 4 and 4 and then drop a line
+  // from the before context.
+  // The typing for this is a bool, but it accepts a number.
+  const beforeAfterMax = Math.max(options.source.afterLines, options.source.beforeLines);
+  (TraceKit as any).linesOfContext = beforeAfterMax * 2 + 1;
+}
+
+export default class BrowserTelemetryImpl implements BrowserTelemetry {
+  private _maxPendingEvents: number;
+  private _maxBreadcrumbs: number;
+
+  private _pendingEvents: { type: string; data: EventData }[] = [];
+  private _client?: LDClientTracking;
+
+  private _breadcrumbs: Breadcrumb[] = [];
+
+  private _inspectorInstances: LDInspection[] = [];
+  private _collectors: Collector[] = [];
+  private _sessionId: string = randomUuidV4();
+
+  constructor(private _options: ParsedOptions) {
+    configureTraceKit(_options.stack);
+
+    // Error collector is always required.
+    this._collectors.push(new ErrorCollector());
+    this._collectors.push(..._options.collectors);
+
+    this._maxPendingEvents = _options.maxPendingEvents;
+    this._maxBreadcrumbs = _options.breadcrumbs.maxBreadcrumbs;
+
+    const urlFilters = [defaultUrlFilter];
+    if (_options.breadcrumbs.http.customUrlFilter) {
+      urlFilters.push(_options.breadcrumbs.http.customUrlFilter);
+    }
+
+    if (_options.breadcrumbs.http.instrumentFetch) {
+      this._collectors.push(
+        new FetchCollector({
+          urlFilters,
+        }),
+      );
+    }
+
+    if (_options.breadcrumbs.http.instrumentXhr) {
+      this._collectors.push(
+        new XhrCollector({
+          urlFilters,
+        }),
+      );
+    }
+
+    if (_options.breadcrumbs.click) {
+      this._collectors.push(new ClickCollector());
+    }
+
+    if (_options.breadcrumbs.keyboardInput) {
+      this._collectors.push(new KeypressCollector());
+    }
+
+    this._collectors.forEach((collector) =>
+      collector.register(this as BrowserTelemetry, this._sessionId),
+    );
+
+    const impl = this;
+    const inspectors: LDInspection[] = [];
+    makeInspectors(_options, inspectors, impl);
+    this._inspectorInstances.push(...inspectors);
+  }
+
+  register(client: LDClientTracking): void {
+    this._client = client;
+    this._pendingEvents.forEach((event) => {
+      this._client?.track(event.type, event.data);
+    });
+  }
+
+  inspectors(): LDInspection[] {
+    return this._inspectorInstances;
+  }
+
+  /**
+   * Capture an event.
+   *
+   * If the LaunchDarkly client SDK is not yet registered, then the event
+   * will be buffered until the client is registered.
+   * @param type The type of event to capture.
+   * @param event The event data.
+   */
+  private _capture(type: string, event: EventData) {
+    if (this._client === undefined) {
+      this._pendingEvents.push({ type, data: event });
+      if (this._pendingEvents.length > this._maxPendingEvents) {
+        // TODO: Log when pending events must be dropped. (SDK-915)
+        this._pendingEvents.shift();
+      }
+    }
+    this._client?.track(type, event);
+  }
+
+  captureError(exception: Error): void {
+    const validException = exception !== undefined && exception !== null;
+
+    const data: ErrorData = validException
+      ? {
+          type: exception.name || exception.constructor?.name || GENERIC_EXCEPTION,
+          // Only coalesce null/undefined, not empty.
+          message: exception.message ?? MISSING_MESSAGE,
+          stack: parse(exception, this._options.stack),
+          breadcrumbs: [...this._breadcrumbs],
+          sessionId: this._sessionId,
+        }
+      : {
+          type: GENERIC_EXCEPTION,
+          message: NULL_EXCEPTION_MESSAGE,
+          stack: { frames: [] },
+          breadcrumbs: [...this._breadcrumbs],
+          sessionId: this._sessionId,
+        };
+    this._capture(ERROR_KEY, data);
+  }
+
+  captureErrorEvent(errorEvent: ErrorEvent): void {
+    this.captureError(errorEvent.error);
+  }
+
+  captureSession(sessionEvent: EventData): void {
+    this._capture(SESSION_CAPTURE_KEY, { ...sessionEvent, breadcrumbs: [...this._breadcrumbs] });
+  }
+
+  addBreadcrumb(breadcrumb: Breadcrumb): void {
+    this._breadcrumbs.push(breadcrumb);
+    if (this._breadcrumbs.length > this._maxBreadcrumbs) {
+      this._breadcrumbs.shift();
+    }
+  }
+
+  close(): void {
+    this._collectors.forEach((collector) => collector.unregister());
+  }
+
+  /**
+   * Used to automatically collect flag usage for breacrumbs.
+   *
+   * When session replay is in use the data is also forwarded to the session
+   * replay collector.
+   *
+   * @internal
+   */
+  handleFlagUsed(flagKey: string, detail: LDEvaluationDetail, _context?: LDContext): void {
+    const breadcrumb: FeatureManagementBreadcrumb = {
+      type: 'flag-evaluated',
+      data: {
+        key: flagKey,
+        value: safeValue(detail.value),
+      },
+      timestamp: new Date().getTime(),
+      class: 'feature-management',
+      level: 'info',
+    };
+    this.addBreadcrumb(breadcrumb);
+  }
+
+  /**
+   * Used to automatically collect flag detail changes.
+   *
+   * When session replay is in use the data is also forwarded to the session
+   * replay collector.
+   *
+   * @internal
+   */
+  handleFlagDetailChanged(flagKey: string, detail: LDEvaluationDetail): void {
+    const breadcrumb: FeatureManagementBreadcrumb = {
+      type: 'flag-detail-changed',
+      data: {
+        key: flagKey,
+        value: safeValue(detail.value),
+      },
+      timestamp: new Date().getTime(),
+      class: 'feature-management',
+      level: 'info',
+    };
+
+    this.addBreadcrumb(breadcrumb);
+  }
+}
diff --git a/packages/telemetry/browser-telemetry/src/api/BrowserTelemetry.ts b/packages/telemetry/browser-telemetry/src/api/BrowserTelemetry.ts
new file mode 100644
index 000000000..79a06afea
--- /dev/null
+++ b/packages/telemetry/browser-telemetry/src/api/BrowserTelemetry.ts
@@ -0,0 +1,77 @@
+import type { LDInspection } from '@launchdarkly/js-client-sdk';
+
+import { Breadcrumb } from './Breadcrumb';
+import { LDClientTracking } from './client/LDClientTracking';
+
+/**
+ * Interface for browser-based telemetry collection in LaunchDarkly SDKs.
+ *
+ * This interface provides methods for collecting diagnostic information, error
+ * tracking, and SDK usage data in browser environments. It is designed to work
+ * with LaunchDarkly's JavaScript client-side SDKs for browser environments.
+ */
+export interface BrowserTelemetry {
+  /**
+   * Returns an array of active SDK inspectors to use with SDK versions that do
+   * not support hooks.
+   *
+   * @returns An array of {@link LDInspection} objects.
+   */
+  inspectors(): LDInspection[];
+
+  /**
+   * Captures an Error object for telemetry purposes.
+   *
+   * Use this method to manually capture errors during application operation.
+   * Unhandled errors are automatically captures, but this method can be used
+   * to capture errors which were hanled, but are still useful for telemetry.
+   *
+   * @param exception The Error object to capture
+   */
+  captureError(exception: Error): void;
+
+  /**
+   * Captures a browser ErrorEvent for telemetry purposes.
+   *
+   * This method can be used to capture a manually created error event. Use this
+   * function to represent application specific errors which cannot be captured
+   * automatically or are not `Error` types.
+   *
+   * For most errors {@link captureError} should be used.
+   *
+   * @param errorEvent The ErrorEvent to capture
+   */
+  captureErrorEvent(errorEvent: ErrorEvent): void;
+
+  /**
+   * Add a breadcrumb which will be included with telemetry events.
+   *
+   * Many breadcrumbs can be automatically captured, but this method can be
+   * used for capturing manual breadcrumbs. For application specific breadcrumbs
+   * the {@link CustomBreadcrumb} type can be used.
+   *
+   * @param breadcrumb The breadcrumb to add.
+   */
+  addBreadcrumb(breadcrumb: Breadcrumb): void;
+
+  /**
+   * Registers a LaunchDarkly client instance for telemetry tracking.
+   *
+   * This method connects the telemetry system to the specific LaunchDarkly
+   * client instance. The client instance will be used to report telemetry
+   * to LaunchDarkly and also for collecting flag and context data.
+   *
+   * @param client The {@link LDClientTracking} instance to register for
+   * telemetry
+   */
+  register(client: LDClientTracking): void;
+
+  /**
+   * Closes the telemetry system and stops data collection.
+   *
+   * In general usage this method is not required, but it can be used in cases
+   * where collection needs to be stopped independent of application
+   * lifecycle.
+   */
+  close(): void;
+}
diff --git a/packages/telemetry/browser-telemetry/src/api/EventData.ts b/packages/telemetry/browser-telemetry/src/api/EventData.ts
new file mode 100644
index 000000000..8e490e17a
--- /dev/null
+++ b/packages/telemetry/browser-telemetry/src/api/EventData.ts
@@ -0,0 +1,4 @@
+import { ErrorData } from './ErrorData';
+
+// Each type of event should be added to this union.
+export type EventData = ErrorData;
diff --git a/packages/telemetry/browser-telemetry/src/api/client/LDClientTracking.ts b/packages/telemetry/browser-telemetry/src/api/client/LDClientTracking.ts
new file mode 100644
index 000000000..6110f4583
--- /dev/null
+++ b/packages/telemetry/browser-telemetry/src/api/client/LDClientTracking.ts
@@ -0,0 +1,7 @@
+/**
+ * Minimal client interface which allows for tracking. Should work with all client-side
+ * JavaScript packages.
+ */
+export interface LDClientTracking {
+  track(key: string, data?: any, metricValue?: number): void;
+}
diff --git a/packages/telemetry/browser-telemetry/src/api/client/index.ts b/packages/telemetry/browser-telemetry/src/api/client/index.ts
new file mode 100644
index 000000000..d363ce8c7
--- /dev/null
+++ b/packages/telemetry/browser-telemetry/src/api/client/index.ts
@@ -0,0 +1 @@
+export * from './LDClientTracking';
diff --git a/packages/telemetry/browser-telemetry/src/api/index.ts b/packages/telemetry/browser-telemetry/src/api/index.ts
index 5e9233fae..b71214eb4 100644
--- a/packages/telemetry/browser-telemetry/src/api/index.ts
+++ b/packages/telemetry/browser-telemetry/src/api/index.ts
@@ -4,3 +4,4 @@ export * from './ErrorData';
 export * from './Options';
 export * from './Recorder';
 export * from './stack';
+export * from './client';
diff --git a/packages/telemetry/browser-telemetry/src/inspectors.ts b/packages/telemetry/browser-telemetry/src/inspectors.ts
new file mode 100644
index 000000000..9e5415cac
--- /dev/null
+++ b/packages/telemetry/browser-telemetry/src/inspectors.ts
@@ -0,0 +1,32 @@
+import type { LDContext, LDEvaluationDetail, LDInspection } from '@launchdarkly/js-client-sdk';
+
+import BrowserTelemetryImpl from './BrowserTelemetryImpl.js';
+import { ParsedOptions } from './options.js';
+
+export default function makeInspectors(
+  options: ParsedOptions,
+  inspectors: LDInspection[],
+  telemetry: BrowserTelemetryImpl,
+) {
+  if (options.breadcrumbs.evaluations) {
+    inspectors.push({
+      type: 'flag-used',
+      name: 'launchdarkly-browser-telemetry-flag-used',
+      synchronous: true,
+      method(flagKey: string, flagDetail: LDEvaluationDetail, context?: LDContext): void {
+        telemetry.handleFlagUsed(flagKey, flagDetail, context);
+      },
+    });
+  }
+
+  if (options.breadcrumbs.flagChange) {
+    inspectors.push({
+      type: 'flag-detail-changed',
+      name: 'launchdarkly-browser-telemetry-flag-used',
+      synchronous: true,
+      method(flagKey: string, detail: LDEvaluationDetail): void {
+        telemetry.handleFlagDetailChanged(flagKey, detail);
+      },
+    });
+  }
+}