diff --git a/client/ios/App/App/TrekShellPlugin.swift b/client/ios/App/App/TrekShellPlugin.swift
index c946e5474..0414b3598 100644
--- a/client/ios/App/App/TrekShellPlugin.swift
+++ b/client/ios/App/App/TrekShellPlugin.swift
@@ -121,7 +121,10 @@ public class TrekShellPlugin: CAPPlugin, CAPBridgedPlugin, ASWebAuthenticationPr
     }
 
     @objc func openOfflineCopy(_ call: CAPPluginCall) {
-        guard let raw = TrekServerStore.url, let url = URL(string: raw),
+        // With the trailing slash, like the bridge's serverURL: Capacitor only
+        // keeps a navigation in the app when it starts with that exact string,
+        // and hands anything else to Safari.
+        guard let raw = TrekServerStore.url, let url = URL(string: raw.hasSuffix("/") ? raw : raw + "/"),
               let html = try? Data(contentsOf: TrekServerStore.offlineCopyURL) else {
             call.resolve(["opened": false])
             return
diff --git a/client/src/api/nativeAuth.test.ts b/client/src/api/nativeAuth.test.ts
new file mode 100644
index 000000000..70c00c19c
--- /dev/null
+++ b/client/src/api/nativeAuth.test.ts
@@ -0,0 +1,19 @@
+import { describe, it, expect, vi } from 'vitest'
+import { nativeAuthApi } from './nativeAuth'
+import { apiClient } from './client'
+
+vi.mock('./client', () => ({ apiClient: { post: vi.fn() } }))
+
+describe('nativeAuthApi', () => {
+  it('mints a hand-off code for a challenge', async () => {
+    vi.mocked(apiClient.post).mockResolvedValue({ data: { code: 'c1' } })
+    await expect(nativeAuthApi.handoff('ab'.repeat(32))).resolves.toEqual({ code: 'c1' })
+    expect(apiClient.post).toHaveBeenCalledWith('/auth/native/handoff', { challenge: 'ab'.repeat(32) })
+  })
+
+  it('redeems the code with its verifier', async () => {
+    vi.mocked(apiClient.post).mockResolvedValue({ data: { ok: true } })
+    await expect(nativeAuthApi.exchange({ code: 'c1', verifier: 'v'.repeat(64) })).resolves.toBeUndefined()
+    expect(apiClient.post).toHaveBeenCalledWith('/auth/native/exchange', { code: 'c1', verifier: 'v'.repeat(64) })
+  })
+})
diff --git a/client/src/native/platform.test.ts b/client/src/native/platform.test.ts
new file mode 100644
index 000000000..1647f13f0
--- /dev/null
+++ b/client/src/native/platform.test.ts
@@ -0,0 +1,33 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest'
+import { Capacitor } from '@capacitor/core'
+import { isNativeApp, isNativeIos, nativeServerHost } from './platform'
+
+vi.mock('@capacitor/core', () => ({ Capacitor: { isNativePlatform: vi.fn(), getPlatform: vi.fn() } }))
+
+beforeEach(() => {
+  vi.mocked(Capacitor.isNativePlatform).mockReturnValue(true)
+  vi.mocked(Capacitor.getPlatform).mockReturnValue('ios')
+})
+
+describe('platform', () => {
+  it('tells the app from a browser', () => {
+    expect(isNativeApp()).toBe(true)
+    vi.mocked(Capacitor.isNativePlatform).mockReturnValue(false)
+    expect(isNativeApp()).toBe(false)
+  })
+
+  it('narrows to iOS', () => {
+    expect(isNativeIos()).toBe(true)
+    vi.mocked(Capacitor.getPlatform).mockReturnValue('android')
+    expect(isNativeIos()).toBe(false)
+    vi.mocked(Capacitor.getPlatform).mockReturnValue('ios')
+    vi.mocked(Capacitor.isNativePlatform).mockReturnValue(false)
+    expect(isNativeIos()).toBe(false)
+  })
+
+  it('names the server the WebView sits on, only inside the app', () => {
+    expect(nativeServerHost()).toBe(window.location.host)
+    vi.mocked(Capacitor.isNativePlatform).mockReturnValue(false)
+    expect(nativeServerHost()).toBeNull()
+  })
+})