diff --git a/.github/workflows/browser.yml b/.github/workflows/browser.yml
index ca33545f13..9556add47e 100644
--- a/.github/workflows/browser.yml
+++ b/.github/workflows/browser.yml
@@ -42,3 +42,89 @@ jobs:
           package_name: '@launchdarkly/js-client-sdk'
           pr_number: ${{ github.event.number }}
           size_limit: 25000
+
+      # Contract Tests
+      - name: Install contract test dependencies
+        run: yarn workspaces focus browser-contract-test-adapter browser-contract-test-service
+
+      - name: Install Playwright browsers
+        run: yarn workspace browser-contract-test-service install-playwright-browsers
+
+      - name: Build contract test adapter
+        run: yarn workspace browser-contract-test-adapter run build
+
+      - name: Build contract test entity (browser app)
+        run: yarn workspace browser-contract-test-service run build
+
+      - name: Start contract test adapter in background
+        run: |
+          yarn workspace browser-contract-test-adapter run start > /tmp/adapter.log 2>&1 &
+          echo $! > /tmp/adapter.pid
+
+      - name: Serve browser app with http-server
+        run: |
+          npx http-server packages/sdk/browser/contract-tests/entity/dist -p 5173 --cors > /tmp/http-server.log 2>&1 &
+          echo $! > /tmp/http-server.pid
+
+      - name: Wait for services to be ready
+        run: |
+          echo "Waiting for adapter on port 8001..."
+          for i in {1..30}; do
+            if nc -z localhost 8001; then
+              echo "Adapter WebSocket ready"
+              break
+            fi
+            if [ $i -eq 30 ]; then
+              echo "Timeout waiting for adapter"
+              cat /tmp/adapter.log
+              exit 1
+            fi
+            sleep 1
+          done
+
+          echo "Waiting for HTTP server on port 5173..."
+          for i in {1..30}; do
+            if curl -s http://localhost:5173 > /dev/null; then
+              echo "HTTP server ready"
+              break
+            fi
+            if [ $i -eq 30 ]; then
+              echo "Timeout waiting for HTTP server"
+              cat /tmp/http-server.log
+              exit 1
+            fi
+            sleep 1
+          done
+
+      - name: Open browser app in headless Chromium
+        run: |
+          node packages/sdk/browser/contract-tests/entity/open-browser.mjs http://localhost:5173 > /tmp/playwright.log 2>&1 &
+          echo $! > /tmp/playwright.pid
+          sleep 5  # Give the browser time to initialize and connect via WebSocket
+
+      - name: Run contract tests
+        uses: launchdarkly/gh-actions/actions/contract-tests@21174f3a7f3aa3e3121227ec91842e8a1ebeec6e
+        with:
+          test_service_port: 8000
+          token: ${{ secrets.GITHUB_TOKEN }}
+          extra_params: '--skip-from=${{ github.workspace }}/packages/sdk/browser/contract-tests/suppressions.txt --stop-service-at-end'
+
+      - name: Print logs on failure
+        if: failure()
+        run: |
+          echo "=== Adapter Log ==="
+          cat /tmp/adapter.log || echo "No adapter log"
+          echo "=== HTTP Server Log ==="
+          cat /tmp/http-server.log || echo "No http-server log"
+          echo "=== Playwright Log ==="
+          cat /tmp/playwright.log || echo "No playwright log"
+
+      - name: Cleanup contract test services
+        if: always()
+        run: |
+          [ -f /tmp/playwright.pid ] && kill $(cat /tmp/playwright.pid) || true
+          [ -f /tmp/http-server.pid ] && kill $(cat /tmp/http-server.pid) || true
+          [ -f /tmp/adapter.pid ] && kill $(cat /tmp/adapter.pid) || true
+          pkill -f "playwright" || true
+          pkill -f "http-server" || true
+          pkill -f "browser-contract-test-adapter" || true
diff --git a/packages/sdk/browser/contract-tests/README.md b/packages/sdk/browser/contract-tests/README.md
new file mode 100644
index 0000000000..73397575c2
--- /dev/null
+++ b/packages/sdk/browser/contract-tests/README.md
@@ -0,0 +1,53 @@
+# Browser SDK Contract Tests
+
+This directory contains the contract test implementation for the LaunchDarkly Browser SDK using the [SDK Test Harness](https://github.com/launchdarkly/sdk-test-harness).
+
+## Architecture
+
+The browser contract tests consist of three components:
+
+1. **Adapter** (`adapter/`): A Node.js server that:
+   - Exposes a REST API on port 8000 for the test harness
+   - Runs a WebSocket server on port 8001 for browser communication
+   - Translates REST commands to WebSocket messages
+
+2. **Entity** (`entity/`): A browser application (Vite app) that:
+   - Connects to the adapter via WebSocket
+   - Implements the actual SDK test logic
+   - Runs the Browser SDK in a real browser environment
+
+3. **Test Harness**: The SDK test harness that:
+   - Sends test commands via REST API to the adapter (port 8000)
+   - Validates SDK behavior across different scenarios
+
+## Running Locally
+
+### Prerequisites
+
+- Node.js 18 or later
+- Yarn
+- A modern browser (for manual testing)
+
+### Quick Start
+
+```bash
+# From the repository root
+./packages/sdk/browser/contract-tests/run-test-service.sh
+```
+
+This script will:
+1. Start the adapter (WebSocket bridge)
+2. Start the entity (browser app with Vite dev server)
+3. Open the browser app in your default browser
+
+The services will be available at:
+- Adapter REST API: http://localhost:8000
+- Adapter WebSocket: ws://localhost:8001
+- Browser App: http://localhost:5173
+
+You then run the `sdk-test-harness`. More information is available here: https://github.com/launchdarkly/sdk-test-harness
+
+Example with local clone of the test harness:
+```bash
+go run . --url http://localhost:8123 -skip-from path-to-your-js-core-clone/packages/sdk/browser/contract-tests/suppressions.txt
+```
diff --git a/packages/sdk/browser/contract-tests/entity/open-browser.mjs b/packages/sdk/browser/contract-tests/entity/open-browser.mjs
new file mode 100644
index 0000000000..ce63f7f843
--- /dev/null
+++ b/packages/sdk/browser/contract-tests/entity/open-browser.mjs
@@ -0,0 +1,42 @@
+#!/usr/bin/env node
+
+/**
+ * Opens a headless browser and navigates to the contract test entity page.
+ * Keeps the browser open until the process is terminated.
+ *
+ * Usage: node open-browser.mjs [url]
+ * Default URL: http://localhost:5173
+ */
+
+import { chromium } from 'playwright';
+
+const url = process.argv[2] || 'http://localhost:5173';
+
+console.log(`Opening headless browser at ${url}...`);
+
+const browser = await chromium.launch({
+  headless: true,
+  args: ['--no-sandbox', '--disable-setuid-sandbox']
+});
+
+const context = await browser.newContext();
+const page = await context.newPage();
+
+// Log console messages from the browser
+page.on('console', (msg) => {
+  console.log(`[Browser Console] ${msg.type()}: ${msg.text()}`);
+});
+
+// Log page errors
+page.on('pageerror', (error) => {
+  console.error(`[Browser Error] ${error.message}`);
+});
+
+await page.goto(url);
+
+console.log('Browser is open and running. Press Ctrl+C to close.');
+
+// Keep the process alive
+await new Promise(() => {
+  // Intentionally never resolve - keeps browser open until process is killed
+});
diff --git a/packages/sdk/browser/contract-tests/entity/package.json b/packages/sdk/browser/contract-tests/entity/package.json
index 9d359fb812..6994e63bb1 100644
--- a/packages/sdk/browser/contract-tests/entity/package.json
+++ b/packages/sdk/browser/contract-tests/entity/package.json
@@ -5,6 +5,7 @@
   "type": "module",
   "description": "Contract test service implementation for @launchdarkly/js-client-sdk",
   "scripts": {
+    "install-playwright-browsers": "playwright install --with-deps chromium",
     "start": "tsc --noEmit && vite --open=true",
     "build": "tsc --noEmit && vite build",
     "lint": "eslint ./src",
@@ -24,6 +25,7 @@
     "eslint-plugin-import": "^2.27.5",
     "eslint-plugin-jest": "^27.6.3",
     "eslint-plugin-prettier": "^5.0.0",
+    "playwright": "^1.49.1",
     "prettier": "^3.0.0",
     "typescript": "^5.5.3",
     "vite": "^5.4.1"