feat: Add Dev Server Integration

.github/workflows/main.yml

@@ -30,7 +30,12 @@ jobs:
       run: yarn build:setup
 
     - name: Setup xvfb
-      run: xvfb-run -a yarn run vscode:prepublish 
+      run: xvfb-run -a yarn run vscode:prepublish
+      env:
+        LD_ANALYTICS_CLIENT_ID: ${{ secrets.LD_ANALYTICS_CLIENT_ID }}
+        LD_ANALYTICS_BASE_URL: ${{ secrets.LD_ANALYTICS_BASE_URL }}
+        LD_ANALYTICS_STREAM_URL: ${{ secrets.LD_ANALYTICS_STREAM_URL }}
+        LD_ANALYTICS_EVENTS_URL: ${{ secrets.LD_ANALYTICS_EVENTS_URL }}
 
     - name: Run xvfb test
       run: xvfb-run -a yarn test

.github/workflows/release.yml

@@ -14,6 +14,11 @@ on:
 jobs:
   build:
     runs-on: ubuntu-latest
+    env:
+      LD_ANALYTICS_CLIENT_ID: ${{ secrets.LD_ANALYTICS_CLIENT_ID }}
+      LD_ANALYTICS_BASE_URL: ${{ secrets.LD_ANALYTICS_BASE_URL }}
+      LD_ANALYTICS_STREAM_URL: ${{ secrets.LD_ANALYTICS_STREAM_URL }}
+      LD_ANALYTICS_EVENTS_URL: ${{ secrets.LD_ANALYTICS_EVENTS_URL }}
 
     steps:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # 4.2.2

.gitignore

@@ -8,4 +8,5 @@ coderefs/
 .vscode/settings.json
 .idea
 .yarn/
-package-lock.json
+package-lock.json
+.env*

README.md

@@ -41,6 +41,7 @@ The LaunchDarkly VS Code extension requires authentication using a **Personal Ac
 - [Quick Links](#quick-links) to LaunchDarkly
 - [Flags in File](#flags-in-file)
 - [Flag Lens](#flag-lens)
+- [Dev Server Integration](#dev-server-integration): connect to a local dev-server for local development and testing with local flag values and overrides
 
 Read our official documentation about this extension at <https://docs.launchdarkly.com/integrations/vscode>
 
@@ -109,6 +110,48 @@ __Variation Information__: Which variation or value of the flag is currently bei
 
 This is OFF by default. It can be enabled through Settings > LaunchDarkly Extension > Enable Flag Lens.
 
+### Dev Server Integration
+
+The extension allows for integrating with the [LaunchDarkly CLI dev-server](https://launchdarkly.com/docs/guides/flags/ldcli-dev-server-reference) for local development and testing. When connected, the extension operates in a hybrid mode: it continues using your LaunchDarkly account for API calls and flag metadata while fetching flag values and streaming updates from the local dev-server.
+
+#### Prerequisites
+
+Install the [LaunchDarkly CLI](https://launchdarkly.com/docs/home/getting-started/setting-up/quickstart#install-the-launchdarkly-cli) and start the dev-server:
+
+```bash
+ldcli dev-server
+```
+
+By default, the dev-server runs at `http://localhost:8765`. You can configure a custom URI in Settings > LaunchDarkly Extension > Dev Server URI.
+
+#### Connecting
+
+1. Open the Command Palette (`Cmd/Ctrl + Shift + P`)
+2. Run `LaunchDarkly: Connect to Dev Server`
+3. Confirm the URI or choose "Change URI" to enter a custom one
+
+The status bar will display a dev-server indicator when connected. If the dev-server becomes unavailable, the extension will prompt you to retry, disconnect, or dismiss.
+
+#### Features when connected
+
+- **Local flag values**: The Feature Flag Explorer shows flag values from the dev-server instead of LaunchDarkly cloud, updated in real-time via streaming.
+- **Override management**: Set or remove flag value overrides directly from the extension. Right-click any flag in the explorer and select "Set Dev Server Override" to choose from available variations or enter a custom value. Overridden flags are marked with a visual indicator.
+- **Hover and Code Lens**: Hover tooltips and Flag Lens annotations reflect dev-server values and indicate when a flag is overridden.
+- **Automatic reconnection**: If the extension was previously connected to the dev-server, it will attempt to reconnect on startup.
+
+#### Commands
+
+| Command | Description |
+|---------|-------------|
+| `LaunchDarkly: Connect to Dev Server` | Connect to a running dev-server instance |
+| `LaunchDarkly: Disconnect from Dev Server` | Disconnect and return to LaunchDarkly cloud values |
+| `LaunchDarkly: Set Dev Server Override` | Set a local override value for a flag (available when connected) |
+| `LaunchDarkly: Remove Dev Server Override` | Remove an existing override for a flag (available when connected) |
+
+#### Disconnecting
+
+Run `LaunchDarkly: Disconnect from Dev Server` from the Command Palette. Flag values will revert to those served by LaunchDarkly.
+
 ## Contributing
 
 LaunchDarkly for Visual Studio Code is an [open source project](https://github.com/launchdarkly/ld-vscode). If you experience any issues, please [log an issue on our issue tracker](https://github.com/launchdarkly/ld-vscode/issues). If you'd like to contribute, we're happily taking pull requests.

package.json

@@ -105,6 +105,11 @@
 					"type": "string",
 					"default": "https://stream.launchdarkly.com",
 					"markdownDescription": "LaunchDarkly stream URI. Change only if you are using the Relay Proxy. [More information](https://docs.launchdarkly.com/home/advanced/relay-proxy/using)"
+				},
+				"launchdarkly.devServerUri": {
+					"type": "string",
+					"default": "http://localhost:8765",
+					"markdownDescription": "URI for the LaunchDarkly CLI dev-server. Used for local development and testing. [More information](https://launchdarkly.com/docs/guides/flags/ldcli-dev-server-reference)"
 				}
 			}
 		},
@@ -256,6 +261,24 @@
 			{
 				"command": "launchdarkly.signOut",
 				"title": "LaunchDarkly: Sign Out"
+			},
+			{
+				"command": "launchdarkly.connectDevServer",
+				"title": "LaunchDarkly: Connect to Dev Server"
+			},
+			{
+				"command": "launchdarkly.disconnectDevServer",
+				"title": "LaunchDarkly: Disconnect from Dev Server"
+			},
+			{
+				"command": "launchdarkly.setDevServerOverride",
+				"title": "LaunchDarkly: Set Dev Server Override",
+				"icon": "$(edit)"
+			},
+			{
+				"command": "launchdarkly.removeDevServerOverride",
+				"title": "LaunchDarkly: Remove Dev Server Override",
+				"icon": "$(close)"
 			}
 		],
 		"menus": {
@@ -312,11 +335,19 @@
 					"command": "launchdarkly.enableCodeLens",
 					"when": "false"
 				},
-				{
-					"command": "launchdarkly.setMaintainer",
-					"when": "false"
-				}
-			],
+			{
+				"command": "launchdarkly.setMaintainer",
+				"when": "false"
+			},
+			{
+				"command": "launchdarkly.setDevServerOverride",
+				"when": "launchdarkly:devServerConnected"
+			},
+			{
+				"command": "launchdarkly.removeDevServerOverride",
+				"when": "launchdarkly:devServerConnected"
+			}
+		],
 			"editor/context": [
 				{
 					"command": "launchdarkly.openInLaunchDarkly",
@@ -406,6 +437,16 @@
 					"command": "launchdarkly.openBrowser",
 					"when": "view == launchdarklyFeatureFlags && viewItem == flagViewBrowser",
 					"group": "inline"
+				},
+				{
+				"command": "launchdarkly.setDevServerOverride",
+				"when": "view == launchdarklyFeatureFlags && launchdarkly:devServerConnected && (viewItem == flagParentItem || viewItem == flagParentItemOverridden)",
+				"group": "devserver@1"
+				},
+				{
+				"command": "launchdarkly.removeDevServerOverride",
+				"when": "view == launchdarklyFeatureFlags && launchdarkly:devServerConnected && viewItem == flagParentItemOverridden",
+				"group": "devserver@2"
 				}
 			]
 		},
@@ -507,6 +548,7 @@
 		"@vscode/test-electron": "^2.3.8",
 		"chai": "^4.3.10",
 		"clean-webpack-plugin": "4.0.0",
+		"dotenv": "^17.3.1",
 		"eslint": "8.55.0",
 		"eslint-config-prettier": "9.1.0",
 		"expect": "^26.1.0",
@@ -532,13 +574,14 @@
 		"@types/lodash": "4.14.116",
 		"@types/opn": "5.1.0",
 		"ajv": "^6.12.6",
-		"axios": "^1.12.0",
+		"axios": "1.13.5",
 		"axios-retry": "4.0.0",
 		"axios-retry-after": "2.0.0",
 		"csv-parser": "^2.3.3",
 		"form-data": "^4.0.4",
 		"gunzip-maybe": "^1.4.2",
 		"launchdarkly-api-typescript": "6.0.0",
+		"launchdarkly-node-client-sdk": "^3.3.1",
 		"lodash": "^4.17.23",
 		"lodash.debounce": "4.0.8",
 		"lodash.kebabcase": "4.1.1",

src/analytics.ts

@@ -0,0 +1,104 @@
+import * as LDClient from 'launchdarkly-node-client-sdk';
+import { Disposable, env } from 'vscode';
+
+export interface AnalyticsConfig {
+	clientSideId: string;
+	baseUrl: string;
+	streamUrl: string;
+	eventsUrl: string;
+}
+
+function getConfigFromEnv(): AnalyticsConfig | null {
+	const clientSideId = process.env.LD_ANALYTICS_CLIENT_ID;
+	const baseUrl = process.env.LD_ANALYTICS_BASE_URL;
+	const streamUrl = process.env.LD_ANALYTICS_STREAM_URL;
+	const eventsUrl = process.env.LD_ANALYTICS_EVENTS_URL;
+
+	if (!clientSideId || !baseUrl || !streamUrl || !eventsUrl) {
+		return null;
+	}
+	return { clientSideId, baseUrl, streamUrl, eventsUrl };
+}
+
+/**
+ * Internal analytics client using the LaunchDarkly Node Client SDK.
+ * Uses a client-side ID (safe to embed — not a secret) to send
+ * usage telemetry events. Respects VS Code telemetry settings.
+ */
+export class AnalyticsClient implements Disposable {
+	private client: LDClient.LDClient | null = null;
+	private enabled = false;
+	private initPromise: Promise<void> | null = null;
+	private config: AnalyticsConfig | null;
+
+	constructor(config?: AnalyticsConfig | null) {
+		this.config = config ?? getConfigFromEnv();
+	}
+
+	async initialize(extensionVersion: string): Promise<void> {
+		if (!this.config || !env.isTelemetryEnabled) {
+			return;
+		}
+
+		if (this.initPromise) {
+			return this.initPromise;
+		}
+
+		this.initPromise = this.doInitialize(extensionVersion);
+		return this.initPromise;
+	}
+
+	private async doInitialize(extensionVersion: string): Promise<void> {
+		try {
+			const context: LDClient.LDContext = {
+				kind: 'ld-vscode-user',
+				key: env.machineId,
+				vscodeVersion: env.appName,
+				extensionVersion,
+			};
+
+			this.client = LDClient.initialize(this.config.clientSideId, context, {
+				baseUrl: this.config.baseUrl,
+				streamUrl: this.config.streamUrl,
+				eventsUrl: this.config.eventsUrl,
+			});
+			await this.client.waitForInitialization();
+			this.enabled = true;
+
+			env.onDidChangeTelemetryEnabled((telemetryEnabled) => {
+				this.enabled = telemetryEnabled;
+			});
+		} catch (err) {
+			console.error('[LaunchDarkly Analytics] Failed to initialize:', err);
+			this.client = null;
+			this.enabled = false;
+		}
+	}
+
+	track(event: string, data?: LDClient.LDFlagValue): void {
+		if (!this.enabled || !this.client) {
+			return;
+		}
+		try {
+			this.client.track(event, data);
+		} catch (err) {
+			console.error(`[LaunchDarkly Analytics] Failed to track event "${event}":`, err);
+		}
+	}
+
+	async dispose(): Promise<void> {
+		if (this.client) {
+			try {
+				await this.client.flush();
+			} catch {
+				// Best-effort flush on shutdown
+			}
+			this.client.close();
+			this.client = null;
+		}
+		this.enabled = false;
+		this.initPromise = null;
+	}
+}
+
+export const analytics = new AnalyticsClient();

src/commands/configureLaunchDarkly.ts

@@ -4,6 +4,7 @@ import { FlagStore } from '../flagStore';
 import { LDExtensionConfiguration } from '../ldExtensionConfiguration';
 import { CMD_LD_CONFIG } from '../utils/commands';
 import { registerCommand } from '../utils/registerCommand';
+import { analytics } from '../analytics';
 
 export default function configureLaunchDarkly(config: LDExtensionConfiguration) {
 	const configureExtension: Disposable = registerCommand(CMD_LD_CONFIG, async () => {
@@ -16,6 +17,7 @@ export default function configureLaunchDarkly(config: LDExtensionConfiguration)
 				await config.getFlagStore().reload();
 			}
 			await config.getCtx().globalState.update('LDConfigured', true);
+			analytics.track('environment-configured');
 			window.withProgress(
 				{
 					location: ProgressLocation.Notification,