diff --git a/.changeset/slow-seas-lead.md b/.changeset/slow-seas-lead.md
new file mode 100644
index 0000000..5e673b9
--- /dev/null
+++ b/.changeset/slow-seas-lead.md
@@ -0,0 +1,5 @@
+---
+"@ecoflow-api/rest-client": patch
+---
+
+add host URL validation
diff --git a/packages/rest-client/src/lib/RestClient.test.ts b/packages/rest-client/src/lib/RestClient.test.ts
new file mode 100644
index 0000000..8d265d7
--- /dev/null
+++ b/packages/rest-client/src/lib/RestClient.test.ts
@@ -0,0 +1,33 @@
+import { describe, expect, it } from "@jest/globals";
+import { RestClient } from "./RestClient";
+
+describe("RestClient", () => {
+  const createClient = (host: string) =>
+    new RestClient({
+      accessKey: "test-access-key",
+      secretKey: "test-secret-key",
+      host,
+    });
+
+  it("should construct successfully with a valid https host", () => {
+    expect(() => createClient("https://api-e.ecoflow.com")).not.toThrow();
+  });
+
+  it("should construct successfully with a valid http host", () => {
+    expect(() => createClient("http://localhost:3000")).not.toThrow();
+  });
+
+  it("should throw an error with an invalid host URL", () => {
+    expect(() => createClient("invalid-url")).toThrow("Invalid host URL");
+  });
+
+  it("should throw an error with an invalid protocol", () => {
+    expect(() => createClient("sftp://api.ecoflow.com")).toThrow(
+      "Invalid host protocol: http or https expected",
+    );
+  });
+
+  it("should throw an error with an empty host", () => {
+    expect(() => createClient("")).toThrow("Invalid host URL");
+  });
+});
diff --git a/packages/rest-client/src/lib/RestClient.ts b/packages/rest-client/src/lib/RestClient.ts
index 98c1a2d..41ab8fe 100644
--- a/packages/rest-client/src/lib/RestClient.ts
+++ b/packages/rest-client/src/lib/RestClient.ts
@@ -100,6 +100,15 @@ export class RestClient {
    * @constructor
    */
   constructor(opts: RestClientOptions) {
+    const parsed = URL.parse(opts.host);
+    if (!parsed) {
+      throw new Error(`Invalid host URL`);
+    }
+
+    if (parsed.protocol !== "http:" && parsed.protocol !== "https:") {
+      throw new Error(`Invalid host protocol: http or https expected`);
+    }
+
     const generateUrl = (path: string) => `${opts.host}${path}`;
 
     this.requestHandler = new RequestHandler(