diff --git a/packages/browser-sdk/package.json b/packages/browser-sdk/package.json
index c9c13870..61577760 100644
--- a/packages/browser-sdk/package.json
+++ b/packages/browser-sdk/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@reflag/browser-sdk",
-  "version": "1.4.2",
+  "version": "1.4.3",
   "packageManager": "yarn@4.1.1",
   "license": "MIT",
   "repository": {
diff --git a/packages/browser-sdk/src/flag/flags.ts b/packages/browser-sdk/src/flag/flags.ts
index 408d3adc..1a776f6a 100644
--- a/packages/browser-sdk/src/flag/flags.ts
+++ b/packages/browser-sdk/src/flag/flags.ts
@@ -5,7 +5,7 @@ import { ReflagContext } from "../context";
 import { HttpClient } from "../httpClient";
 import { Logger, loggerWithPrefix } from "../logger";
 import RateLimiter from "../rateLimiter";
-import { getLocalStorageAdapter, StorageAdapter } from "../storage";
+import { getDefaultStorageAdapter, StorageAdapter } from "../storage";
 import { createAbortController } from "../utils/abortController";
 import { createEventTarget } from "../utils/eventTarget";
 
@@ -235,7 +235,7 @@ export class FlagsClient {
     this.logger = loggerWithPrefix(logger, "[Flags]");
     this.rateLimiter =
       rateLimiter ?? new RateLimiter(FLAG_EVENTS_PER_MIN, this.logger);
-    this.storage = (cache ? undefined : storage) ?? getLocalStorageAdapter();
+    this.storage = (cache ? undefined : storage) ?? getDefaultStorageAdapter();
     this.cache =
       cache ??
       this.setupCache(this.config.staleTimeMs, this.config.expireTimeMs);
diff --git a/packages/browser-sdk/src/storage.ts b/packages/browser-sdk/src/storage.ts
index ffe5ab08..b031736b 100644
--- a/packages/browser-sdk/src/storage.ts
+++ b/packages/browser-sdk/src/storage.ts
@@ -1,9 +1,19 @@
+import { IS_SERVER } from "./config";
+
 export type StorageAdapter = {
   getItem(key: string): Promise<string | null>;
   setItem(key: string, value: string): Promise<void>;
   removeItem?(key: string): Promise<void>;
 };
 
+export function createNoopStorageAdapter(): StorageAdapter {
+  return {
+    getItem: async () => null,
+    setItem: async () => undefined,
+    removeItem: async () => undefined,
+  };
+}
+
 export function getLocalStorageAdapter(): StorageAdapter {
   if (
     typeof localStorage === "undefined" ||
@@ -24,3 +34,8 @@ export function getLocalStorageAdapter(): StorageAdapter {
     },
   };
 }
+
+export function getDefaultStorageAdapter(): StorageAdapter {
+  if (IS_SERVER) return createNoopStorageAdapter();
+  return getLocalStorageAdapter();
+}
diff --git a/packages/browser-sdk/test/client.test.ts b/packages/browser-sdk/test/client.test.ts
index 48e2b215..bf1fe228 100644
--- a/packages/browser-sdk/test/client.test.ts
+++ b/packages/browser-sdk/test/client.test.ts
@@ -1,4 +1,4 @@
-import { beforeEach, describe, expect, it, vi } from "vitest";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 
 import { ReflagClient } from "../src/client";
 import { FlagsClient } from "../src/flag/flags";
@@ -23,6 +23,10 @@ describe("ReflagClient", () => {
     vi.clearAllMocks();
   });
 
+  afterEach(() => {
+    vi.unstubAllGlobals();
+  });
+
   describe("updateUser", () => {
     it("should update the user context", async () => {
       // and send new user data and trigger flag update
diff --git a/packages/browser-sdk/test/storage.test.ts b/packages/browser-sdk/test/storage.test.ts
new file mode 100644
index 00000000..ffcc5fab
--- /dev/null
+++ b/packages/browser-sdk/test/storage.test.ts
@@ -0,0 +1,45 @@
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+async function loadStorageModule() {
+  vi.resetModules();
+  return import("../src/storage");
+}
+
+describe("storage adapters", () => {
+  afterEach(() => {
+    vi.unstubAllGlobals();
+  });
+
+  it("noop adapter ignores writes", async () => {
+    const { createNoopStorageAdapter } = await loadStorageModule();
+    const adapter = createNoopStorageAdapter();
+
+    expect(await adapter.getItem("key")).toBeNull();
+    await adapter.setItem("key", "value");
+    expect(await adapter.getItem("key")).toBeNull();
+
+    await adapter.removeItem?.("key");
+    expect(await adapter.getItem("key")).toBeNull();
+  });
+
+  it("localStorage adapter throws when localStorage is unavailable", async () => {
+    const { getLocalStorageAdapter } = await loadStorageModule();
+    vi.stubGlobal("localStorage", undefined);
+    expect(() => getLocalStorageAdapter()).toThrowError(
+      "localStorage is not available. Provide a custom storage adapter.",
+    );
+  });
+
+  it("default adapter falls back to noop on server runtimes", async () => {
+    vi.resetModules();
+    vi.stubGlobal("window", undefined);
+    vi.stubGlobal("document", undefined);
+    vi.stubGlobal("localStorage", undefined);
+
+    const { getDefaultStorageAdapter } = await import("../src/storage");
+    const adapter = getDefaultStorageAdapter();
+
+    await adapter.setItem("fallback", "ok");
+    expect(await adapter.getItem("fallback")).toBeNull();
+  });
+});
diff --git a/packages/react-native-sdk/package.json b/packages/react-native-sdk/package.json
index 543c2032..85f1e2b8 100644
--- a/packages/react-native-sdk/package.json
+++ b/packages/react-native-sdk/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@reflag/react-native-sdk",
-  "version": "0.1.2",
+  "version": "0.1.3",
   "license": "MIT",
   "repository": {
     "type": "git",
@@ -32,7 +32,7 @@
   },
   "dependencies": {
     "@react-native-async-storage/async-storage": "^2.2.0",
-    "@reflag/react-sdk": "1.4.2"
+    "@reflag/react-sdk": "1.4.3"
   },
   "peerDependencies": {
     "react": "*",
diff --git a/packages/react-sdk/package.json b/packages/react-sdk/package.json
index 5ff56280..803e2555 100644
--- a/packages/react-sdk/package.json
+++ b/packages/react-sdk/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@reflag/react-sdk",
-  "version": "1.4.2",
+  "version": "1.4.3",
   "license": "MIT",
   "repository": {
     "type": "git",
@@ -37,7 +37,7 @@
     }
   },
   "dependencies": {
-    "@reflag/browser-sdk": "1.4.2"
+    "@reflag/browser-sdk": "1.4.3"
   },
   "peerDependencies": {
     "react": "*",
diff --git a/yarn.lock b/yarn.lock
index ee752c53..f19683f8 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -5036,7 +5036,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@reflag/browser-sdk@npm:1.4.2, @reflag/browser-sdk@workspace:packages/browser-sdk":
+"@reflag/browser-sdk@npm:1.4.3, @reflag/browser-sdk@workspace:packages/browser-sdk":
   version: 0.0.0-use.local
   resolution: "@reflag/browser-sdk@workspace:packages/browser-sdk"
   dependencies:
@@ -5223,7 +5223,7 @@ __metadata:
   dependencies:
     "@react-native-async-storage/async-storage": "npm:^2.2.0"
     "@reflag/eslint-config": "npm:^0.0.2"
-    "@reflag/react-sdk": "npm:1.4.2"
+    "@reflag/react-sdk": "npm:1.4.3"
     "@reflag/tsconfig": "npm:^0.0.2"
     "@types/react": "npm:^19.0.12"
     eslint: "npm:^9.21.0"
@@ -5235,11 +5235,11 @@ __metadata:
   languageName: unknown
   linkType: soft
 
-"@reflag/react-sdk@npm:1.4.2, @reflag/react-sdk@workspace:^, @reflag/react-sdk@workspace:packages/react-sdk":
+"@reflag/react-sdk@npm:1.4.3, @reflag/react-sdk@workspace:^, @reflag/react-sdk@workspace:packages/react-sdk":
   version: 0.0.0-use.local
   resolution: "@reflag/react-sdk@workspace:packages/react-sdk"
   dependencies:
-    "@reflag/browser-sdk": "npm:1.4.2"
+    "@reflag/browser-sdk": "npm:1.4.3"
     "@reflag/eslint-config": "npm:^0.0.2"
     "@reflag/tsconfig": "npm:^0.0.2"
     "@testing-library/react": "npm:^15.0.7"