diff --git a/apps/web/src/components/LoginScreen.tsx b/apps/web/src/components/LoginScreen.tsx
index a2732be7..ddd650af 100644
--- a/apps/web/src/components/LoginScreen.tsx
+++ b/apps/web/src/components/LoginScreen.tsx
@@ -1,7 +1,7 @@
 import { useState, type FormEvent } from "react";
 import { LockKeyhole } from "lucide-react";
 import { useTranslation } from "react-i18next";
-import { resolveInstanceUrlInput } from "@edgeever/shared";
+import { normalizeInstanceUrl } from "@edgeever/shared";
 import { Button } from "@/components/ui/button";
 import { GitHubRepositoryLink } from "@/components/GitHubRepositoryLink";
 import { Input } from "@/components/ui/input";
@@ -39,7 +39,7 @@ export const LoginScreen = ({ error, instanceUrl: initialInstanceUrl, isSubmitti
     }
 
     onSubmit({
-      ...(initialInstanceUrl !== undefined ? { instanceUrl: resolveInstanceUrlInput(instanceUrl) } : {}),
+      ...(initialInstanceUrl !== undefined ? { instanceUrl: normalizeInstanceUrl(instanceUrl) } : {}),
       username: username.trim(),
       password,
     });
@@ -83,11 +83,14 @@ export const LoginScreen = ({ error, instanceUrl: initialInstanceUrl, isSubmitti
             <label className="block">
               <span className="mb-2 block text-sm font-semibold text-slate-700">{t("login.desktopInstanceUrl")}</span>
               <Input
+                autoCapitalize="none"
                 autoComplete="url"
+                autoCorrect="off"
                 className="h-11 rounded-lg bg-slate-50/50 px-3.5 focus-visible:bg-card focus-visible:ring-2 focus-visible:ring-emerald-500/20"
+                inputMode="url"
                 placeholder={t("login.instanceUrlPlaceholder")}
                 required
-                type="url"
+                spellCheck={false}
                 value={instanceUrl}
                 onChange={(event) => setInstanceUrl(event.target.value)}
               />
diff --git a/apps/web/src/lib/api.test.mjs b/apps/web/src/lib/api.test.mjs
index e7c03da4..2891d2b4 100644
--- a/apps/web/src/lib/api.test.mjs
+++ b/apps/web/src/lib/api.test.mjs
@@ -74,7 +74,7 @@ const {
 
 describe("desktop instance setup", () => {
   test("can retry with a valid URL after invalid input", async () => {
-    await expect(saveDesktopApiBaseUrl("not-an-instance")).rejects.toThrow();
+    await expect(saveDesktopApiBaseUrl("ftp://example.com")).rejects.toThrow();
 
     const saving = saveDesktopApiBaseUrl(" https://notes.example.com/ ");
     await Promise.resolve();
@@ -100,6 +100,25 @@ describe("desktop instance setup", () => {
     await expect(saving).resolves.toBe("https://demo.edgeever.org");
   });
 
+  test("prefixes https when the instance host has no protocol", async () => {
+    calls.length = 0;
+    const saving = saveDesktopApiBaseUrl(" example.workers.dev/ ");
+    await Promise.resolve();
+    expect(calls).toEqual([["bridge:start", "https://example.workers.dev"]]);
+    completeSave();
+    await expect(saving).resolves.toBe("https://example.workers.dev");
+    expect(storage.get(DESKTOP_API_BASE_URL_STORAGE_KEY)).toBe("https://example.workers.dev");
+  });
+
+  test("keeps an explicit http instance URL", async () => {
+    calls.length = 0;
+    const saving = saveDesktopApiBaseUrl("http://127.0.0.1:8787/");
+    await Promise.resolve();
+    expect(calls).toEqual([["bridge:start", "http://127.0.0.1:8787"]]);
+    completeSave();
+    await expect(saving).resolves.toBe("http://127.0.0.1:8787");
+  });
+
   test("clears the cached session when the login form changes instances", async () => {
     calls.length = 0;
     window.edgeeverDesktop.apiBaseUrl = "https://notes.example.com";
diff --git a/apps/web/src/lib/api.ts b/apps/web/src/lib/api.ts
index 92a008a2..580b57ed 100644
--- a/apps/web/src/lib/api.ts
+++ b/apps/web/src/lib/api.ts
@@ -4,7 +4,7 @@ import {
   type EdgeEverClientRequestContext,
 } from "@edgeever/client";
 import type { AuthSession } from "@edgeever/shared";
-import { resolveInstanceUrlInput } from "@edgeever/shared";
+import { normalizeInstanceUrl } from "@edgeever/shared";
 import { createClientUuid } from "./client-id";
 
 export { ApiRequestError };
@@ -121,7 +121,7 @@ export class DesktopInstanceUrlError extends Error {
 }
 
 export const saveDesktopApiBaseUrl = async (value: string) => {
-  const normalized = resolveInstanceUrlInput(value).replace(/\/$/, "");
+  const normalized = normalizeInstanceUrl(value);
   let parsed: URL;
   try {
     parsed = new URL(normalized);
diff --git a/packages/shared/src/i18n/en-US.ts b/packages/shared/src/i18n/en-US.ts
index 7a611be1..87d403af 100644
--- a/packages/shared/src/i18n/en-US.ts
+++ b/packages/shared/src/i18n/en-US.ts
@@ -262,7 +262,7 @@ export const enUS = {
     desktopInstanceUrl: "Instance URL",
     desktopInstanceContinue: "Continue",
     desktopChangeInstance: "Change instance URL",
-    desktopInstanceUrlInvalid: "Enter a valid instance URL beginning with http:// or https://.",
+    desktopInstanceUrlInvalid: "Enter a valid instance URL.",
     instanceUrlPlaceholder: "https://demo.edgeever.org",
   },
   nav: {
diff --git a/packages/shared/src/i18n/ja.ts b/packages/shared/src/i18n/ja.ts
index c5779100..4f004a66 100644
--- a/packages/shared/src/i18n/ja.ts
+++ b/packages/shared/src/i18n/ja.ts
@@ -262,7 +262,7 @@ export const ja = {
     desktopInstanceUrl: "インスタンス URL",
     desktopInstanceContinue: "続ける",
     desktopChangeInstance: "インスタンス URL を変更",
-    desktopInstanceUrlInvalid: "http:// または https:// で始まる有効なインスタンス URL を入力してください。",
+    desktopInstanceUrlInvalid: "有効なインスタンス URL を入力してください。",
     instanceUrlPlaceholder: "https://demo.edgeever.org",
   },
   nav: {
diff --git a/packages/shared/src/i18n/zh-CN.ts b/packages/shared/src/i18n/zh-CN.ts
index b36d57d3..c0e177a2 100644
--- a/packages/shared/src/i18n/zh-CN.ts
+++ b/packages/shared/src/i18n/zh-CN.ts
@@ -262,7 +262,7 @@ export const zhCN = {
     desktopInstanceUrl: "实例地址",
     desktopInstanceContinue: "继续",
     desktopChangeInstance: "更换实例地址",
-    desktopInstanceUrlInvalid: "请输入以 http:// 或 https:// 开头的有效实例地址。",
+    desktopInstanceUrlInvalid: "请输入有效的实例地址。",
     instanceUrlPlaceholder: "https://demo.edgeever.org",
   },
   nav: {
diff --git a/packages/shared/src/public-demo.test.mjs b/packages/shared/src/public-demo.test.mjs
index 0a881bec..196ed937 100644
--- a/packages/shared/src/public-demo.test.mjs
+++ b/packages/shared/src/public-demo.test.mjs
@@ -1,5 +1,5 @@
 import { describe, expect, test } from "bun:test";
-import { PUBLIC_DEMO_INSTANCE_URL, resolveInstanceUrlInput } from "./public-demo.ts";
+import { PUBLIC_DEMO_INSTANCE_URL, normalizeInstanceUrl, resolveInstanceUrlInput } from "./public-demo.ts";
 
 describe("public demo instance URL", () => {
   test("maps the App Review 'demo' alias to the public instance", () => {
@@ -16,4 +16,14 @@ describe("public demo instance URL", () => {
     expect(resolveInstanceUrlInput("demo.example.com")).toBe("demo.example.com");
     expect(resolveInstanceUrlInput("")).toBe("");
   });
+
+  test("prefixes https when a host has no protocol", () => {
+    expect(normalizeInstanceUrl("example.workers.dev")).toBe("https://example.workers.dev");
+    expect(normalizeInstanceUrl(" example.workers.dev/ ")).toBe("https://example.workers.dev");
+    expect(normalizeInstanceUrl("https://notes.example.com/")).toBe("https://notes.example.com");
+    expect(normalizeInstanceUrl("http://127.0.0.1:8787")).toBe("http://127.0.0.1:8787");
+    expect(normalizeInstanceUrl("ftp://example.com")).toBe("ftp://example.com");
+    expect(normalizeInstanceUrl("demo")).toBe(PUBLIC_DEMO_INSTANCE_URL);
+    expect(normalizeInstanceUrl("")).toBe("");
+  });
 });
diff --git a/packages/shared/src/public-demo.ts b/packages/shared/src/public-demo.ts
index 099b018c..321fcbb6 100644
--- a/packages/shared/src/public-demo.ts
+++ b/packages/shared/src/public-demo.ts
@@ -16,3 +16,13 @@ export const resolveInstanceUrlInput = (value: string) => {
   }
   return publicDemoAliasHost(trimmed) === "demo" ? PUBLIC_DEMO_INSTANCE_URL : trimmed;
 };
+
+/** Resolve aliases, default missing schemes to https://, and drop trailing slashes. */
+export const normalizeInstanceUrl = (value: string) => {
+  const resolved = resolveInstanceUrlInput(value);
+  if (!resolved) {
+    return resolved;
+  }
+  const withProtocol = /:\/\//.test(resolved) ? resolved : `https://${resolved}`;
+  return withProtocol.replace(/\/+$/, "");
+};
diff --git a/tests/login-screen-style.test.ts b/tests/login-screen-style.test.ts
index c4ff8161..dc3351a9 100644
--- a/tests/login-screen-style.test.ts
+++ b/tests/login-screen-style.test.ts
@@ -11,4 +11,10 @@ describe("login screen chrome", () => {
     expect(loginScreen).toContain("backdrop-blur-md");
     expect(loginScreen).not.toContain("slate-900-rgb");
   });
+
+  test("accepts instance hosts without a protocol", () => {
+    expect(loginScreen).toContain("normalizeInstanceUrl");
+    expect(loginScreen).toContain('inputMode="url"');
+    expect(loginScreen).not.toContain('type="url"');
+  });
 });