diff --git a/src/__tests__/index.test.tsx b/src/__tests__/index.test.tsx
index bf84291..a0f0e87 100644
--- a/src/__tests__/index.test.tsx
+++ b/src/__tests__/index.test.tsx
@@ -1 +1,73 @@
-it.todo('write a test');
+const mockIOSTransact = jest.fn();
+const mockAndroidTransact = jest.fn();
+
+jest.mock('react-native', () => ({
+  Platform: { OS: 'ios', select: (obj: any) => obj.ios ?? obj.default },
+  NativeModules: { TransactReactNative: {} },
+  Appearance: { getColorScheme: () => 'light' },
+  NativeEventEmitter: jest.fn(),
+  DeviceEventEmitter: { addListener: jest.fn() },
+}));
+
+jest.mock('../ios', () => ({
+  AtomicIOS: { transact: (...args: any[]) => mockIOSTransact(...args) },
+}));
+jest.mock('../android', () => ({
+  AtomicAndroid: { transact: (...args: any[]) => mockAndroidTransact(...args) },
+}));
+
+import { Atomic, Step } from '../index';
+
+beforeEach(() => {
+  mockIOSTransact.mockClear();
+  mockAndroidTransact.mockClear();
+});
+
+describe('account deeplink config', () => {
+  it('exposes account as a valid deeplink step', () => {
+    expect(Step.ACCOUNT).toBe('account');
+  });
+
+  it('forwards the account step and accountId through config-to-JSON conversion', () => {
+    Atomic.transact({
+      config: {
+        publicToken: 'pt-abc-123',
+        scope: 'user-link',
+        deeplink: { step: Step.ACCOUNT, accountId: 'abc123' },
+        tasks: [{ operation: 'auth' }],
+      },
+    });
+
+    expect(mockIOSTransact).toHaveBeenCalledTimes(1);
+
+    // The RN bridge serializes the config to JSON before it reaches native.
+    // Round-trip it here to assert the account deeplink survives that conversion.
+    const { config } = mockIOSTransact.mock.calls[0][0];
+    const serialized = JSON.parse(JSON.stringify(config));
+
+    expect(serialized.deeplink).toEqual({
+      step: 'account',
+      accountId: 'abc123',
+    });
+  });
+
+  it('leaves other deeplink steps and payload fields unchanged', () => {
+    Atomic.transact({
+      config: {
+        publicToken: 'pt-abc-123',
+        scope: 'user-link',
+        deeplink: { step: Step.SEARCH_COMPANY, companyId: 'co-1' },
+        tasks: [{ operation: 'auth' }],
+      },
+    });
+
+    const { config } = mockIOSTransact.mock.calls[0][0];
+    const serialized = JSON.parse(JSON.stringify(config));
+
+    expect(serialized.deeplink).toEqual({
+      step: 'search-company',
+      companyId: 'co-1',
+    });
+    expect(serialized.deeplink.accountId).toBeUndefined();
+  });
+});
diff --git a/src/constants.tsx b/src/constants.tsx
index b05c675..8852467 100644
--- a/src/constants.tsx
+++ b/src/constants.tsx
@@ -62,6 +62,7 @@ export const Step = {
   LOGIN_PAYROLL: 'login-payroll',
   SEARCH_COMPANY: 'search-company',
   SEARCH_PAYROLL: 'search-payroll',
+  ACCOUNT: 'account',
 } as const;
 
 export type StepType = (typeof Step)[keyof typeof Step] | (string & {});