diff --git a/src/lib/features/client-feature-toggles/client-feature-streaming.controller.ts b/src/lib/features/client-feature-toggles/client-feature-streaming.controller.ts
index 3f5fb30641e8..04965f0bdf62 100644
--- a/src/lib/features/client-feature-toggles/client-feature-streaming.controller.ts
+++ b/src/lib/features/client-feature-toggles/client-feature-streaming.controller.ts
@@ -1,6 +1,7 @@
 import type { Response } from 'express';
 import Controller from '../../routes/controller';
 import type {
+    IFeatureToggleQuery,
     IFlagResolver,
     IUnleashConfig,
     IUnleashServices,
@@ -10,14 +11,37 @@ import type { IAuthRequest } from '../../routes/unleash-types';
 import { NONE } from '../../types/permissions';
 import type ConfigurationRevisionService from '../feature-toggle/configuration-revision-service';
 import { UPDATE_REVISION } from '../feature-toggle/configuration-revision-service';
+import type { ClientFeatureToggleService } from './client-feature-toggle-service';
+import ApiUser from '../../types/api-user';
+import { ALL, isAllProjects } from '../../types/models/api-token';
+import { querySchema } from '../../schema/feature-schema';
+import hashSum from 'hash-sum';
 
-type SSEClientResponse = Response & { flush: Function };
+type ResponseWithFlush = Response & { flush: Function };
+
+type SSEClientResponse = {
+    req: IAuthRequest;
+    res: ResponseWithFlush;
+};
+
+interface QueryOverride {
+    project?: string[];
+    environment?: string;
+}
+
+interface IMeta {
+    revisionId: number;
+    etag: string;
+    queryHash: string;
+}
 
 export class FeatureStreamingController extends Controller {
     private readonly logger: Logger;
 
     private configurationRevisionService: ConfigurationRevisionService;
 
+    private clientFeatureToggleService: ClientFeatureToggleService;
+
     private flagResolver: IFlagResolver;
 
     private activeConnections: Set<SSEClientResponse>;
@@ -25,11 +49,16 @@ export class FeatureStreamingController extends Controller {
     constructor(
         {
             configurationRevisionService,
-        }: Pick<IUnleashServices, 'configurationRevisionService'>,
+            clientFeatureToggleService,
+        }: Pick<
+            IUnleashServices,
+            'configurationRevisionService' | 'clientFeatureToggleService'
+        >,
         config: IUnleashConfig,
     ) {
         super(config);
         this.configurationRevisionService = configurationRevisionService;
+        this.clientFeatureToggleService = clientFeatureToggleService;
         this.flagResolver = config.flagResolver;
         this.logger = config.getLogger('client-api/streaming.js');
 
@@ -51,7 +80,7 @@ export class FeatureStreamingController extends Controller {
 
     async getFeatureStream(
         req: IAuthRequest,
-        res: SSEClientResponse,
+        res: ResponseWithFlush,
     ): Promise<void> {
         if (!this.flagResolver.isEnabled('streaming')) {
             res.status(403).end();
@@ -68,22 +97,121 @@ export class FeatureStreamingController extends Controller {
         res.write(`data: CONNECTED\n\n`);
         res.flush();
 
-        this.activeConnections.add(res);
+        const connection = { req, res };
+        this.activeConnections.add(connection);
 
         res.on('close', () => {
-            this.activeConnections.delete(res);
+            this.activeConnections.delete(connection);
         });
     }
 
-    private onUpdateRevisionEvent() {
-        for (const res of this.activeConnections) {
+    private async onUpdateRevisionEvent() {
+        for (const connection of this.activeConnections) {
+            const { req, res } = connection;
+
+            if (res.writableEnded) {
+                this.activeConnections.delete(connection);
+                continue;
+            }
+
             try {
-                res.write(`data: UPDATE\n\n`);
+                const update = await this.getClientFeaturesResponse(req);
+                res.write(`data: UPDATE:${JSON.stringify(update)}\n\n`);
                 res.flush();
             } catch (err) {
                 this.logger.info('Failed to send event. Dropping connection.');
-                this.activeConnections.delete(res);
+                this.activeConnections.delete(connection);
+            }
+        }
+    }
+
+    private async getClientFeaturesResponse(req: IAuthRequest) {
+        const query = await this.resolveQuery(req);
+        const meta = await this.calculateMeta(query);
+
+        const features =
+            await this.clientFeatureToggleService.getClientFeatures(query);
+        const segments =
+            await this.clientFeatureToggleService.getActiveSegmentsForClient();
+
+        return {
+            version: 2,
+            features,
+            query,
+            segments,
+            meta,
+        };
+    }
+
+    private async resolveQuery(
+        req: IAuthRequest,
+    ): Promise<IFeatureToggleQuery> {
+        const { user, query } = req;
+
+        const override: QueryOverride = {};
+        if (user instanceof ApiUser) {
+            if (!isAllProjects(user.projects)) {
+                override.project = user.projects;
+            }
+            if (user.environment !== ALL) {
+                override.environment = user.environment;
             }
         }
+
+        return this.prepQuery({
+            ...query,
+            ...override,
+            inlineSegmentConstraints: false,
+        });
+    }
+
+    private paramToArray(param: any) {
+        if (!param) {
+            return param;
+        }
+        return Array.isArray(param) ? param : [param];
+    }
+
+    private async prepQuery({
+        tag,
+        project,
+        namePrefix,
+        environment,
+        inlineSegmentConstraints,
+    }: IFeatureToggleQuery): Promise<IFeatureToggleQuery> {
+        if (
+            !tag &&
+            !project &&
+            !namePrefix &&
+            !environment &&
+            !inlineSegmentConstraints
+        ) {
+            return {};
+        }
+
+        const tagQuery = this.paramToArray(tag);
+        const projectQuery = this.paramToArray(project);
+        const query = await querySchema.validateAsync({
+            tag: tagQuery,
+            project: projectQuery,
+            namePrefix,
+            environment,
+            inlineSegmentConstraints,
+        });
+
+        if (query.tag) {
+            query.tag = query.tag.map((q) => q.split(':'));
+        }
+
+        return query;
+    }
+
+    private async calculateMeta(query: IFeatureToggleQuery): Promise<IMeta> {
+        const revisionId =
+            await this.configurationRevisionService.getMaxRevisionId();
+
+        const queryHash = hashSum(query);
+        const etag = `"${queryHash}:${revisionId}"`;
+        return { revisionId, etag, queryHash };
     }
 }