diff --git a/src/api.test.ts b/src/api.test.ts
new file mode 100644
index 0000000..8cc0694
--- /dev/null
+++ b/src/api.test.ts
@@ -0,0 +1,24 @@
+import { applyMiddleware, legacy_createStore as createStore } from 'redux';
+import { thunk } from 'redux-thunk';
+
+import { requestLogin, requestUserData } from '@/api';
+import rootReducer from '@/reducers';
+
+const createTestStore = () => createStore(rootReducer, undefined, applyMiddleware(thunk));
+
+describe('dev fake users (__DEV__ only)', () => {
+  it.each([
+    ['nonmember', false],
+    ['member', true],
+  ])('logs in "%s" with a fake user without hitting the network', async (username, isMember) => {
+    const store = createTestStore();
+
+    await store.dispatch(requestLogin(username as string, 'any-password'));
+    expect(store.getState().isAuthenticated).toBe(true);
+
+    await store.dispatch(requestUserData(store.getState().userToken ?? ''));
+    expect(store.getState().user?.is_member).toBe(isMember);
+
+    expect(global.fetch).not.toHaveBeenCalled();
+  });
+});
diff --git a/src/api.ts b/src/api.ts
index 43ae88a..e2c89cf 100644
--- a/src/api.ts
+++ b/src/api.ts
@@ -14,10 +14,45 @@ import {
 } from './actions';
 import type { UserRegisterFormValues } from './modules/register/useUserRegister';
 import { AppDispatch } from './reduxStore';
+import type { UserType } from './types/data';
 import { fetchWithTimeout } from './utils';
 
+// Dev builds only (stripped from release builds via __DEV__): log in with one of
+// these usernames and any password to get a fake user, for previewing membership
+// screens without a real account in each state.
+const DEV_FAKE_TOKEN_PREFIX = 'dev-fake-token:';
+const DEV_FAKE_USERS: Record<string, UserType> = {
+  nonmember: {
+    username: 'nonmember',
+    email: 'nonmember@example.test',
+    first_name: 'Ikke',
+    last_name: 'Medlem',
+    is_member: false,
+    is_volunteer: false,
+    last_membership: null,
+  },
+  member: {
+    username: 'member',
+    email: 'member@example.test',
+    first_name: 'Gyldig',
+    last_name: 'Medlem',
+    is_member: true,
+    is_volunteer: false,
+    last_membership: {
+      membership_type: 'standard',
+      // Far future, so useProof's expired-membership check doesn't refetch in a loop
+      end_date: '2099-08-01',
+    },
+  },
+};
+
 export function requestLogin(username: string, password: string) {
   return (dispatch: AppDispatch) => {
+    if (__DEV__ && username in DEV_FAKE_USERS) {
+      dispatch(loginSuccess(username, DEV_FAKE_TOKEN_PREFIX + username));
+      return Promise.resolve();
+    }
+
     // We are now logging in
     dispatch(loginRequest());
 
@@ -53,6 +88,14 @@ export function requestLogin(username: string, password: string) {
 
 export function requestUserData(authToken: string) {
   return (dispatch: AppDispatch) => {
+    if (__DEV__ && authToken.startsWith(DEV_FAKE_TOKEN_PREFIX)) {
+      const fakeUser = DEV_FAKE_USERS[authToken.slice(DEV_FAKE_TOKEN_PREFIX.length)];
+      if (fakeUser) {
+        dispatch(userDataSuccess(fakeUser));
+        return Promise.resolve();
+      }
+    }
+
     // We are now fetching user data
     dispatch(userDataRequest());