Combining Zalo with Email Marketing: When to Use Instant Messaging and When to Send Emails

First, Understand the "Personality" of Each Channel

Zalo is one of the most frequently opened apps by Vietnamese users daily. Messages are typically seen within minutes, making it suitable for urgent, concise information. Email, on the other hand, acts more like an "archive box," where users tend to process messages on desktop or during free time, making it ideal for detailed content that needs to be saved. In cross-border business, treating them as interchangeable can lead to annoyance or missed opportunities.

Three Scenarios Where Zalo Instant Messaging Takes Priority

• Sudden Order Status Changes: For example, shipping delays or backorder fulfillment. Use Zalo OA to push a brief notification so users are immediately informed, reducing customer service pressure.
• Limited-Time Offers or Countdowns: For instance, the last 2 hours of a big sale. Sending reminders via Zalo yields higher conversion rates than email because users don't need to open their inbox to see them.
• Post-Sale Follow-ups or Satisfaction Surveys: Send a 3-question mini survey via Zalo. Users can complete it quickly, which is more user-friendly than a long link in an email.

Two Scenarios Where Email Is More Suitable

When content exceeds 200 words, or requires careful reading, comparison, or saving, email is the better choice. Typical examples include product manuals, quarterly statements, and VIP membership benefits explanations. Additionally, if users haven't added your Zalo OA yet, email is the only official channel to reach them. In such cases, always send formal documents like contracts or invoices via email.

A Simple Coordination Model: 5 Criteria

Before planning any customer communication, run through the following 5 questions to quickly decide which channel to use.

1. Is the information urgent? Yes → Zalo, No → Email.
2. Does the content exceed 150 words? Yes → Email, No → Zalo.
3. Does it require a user response? Yes → Zalo (faster replies), No → Email.
4. Does it include attachments or links? Yes → Email (links on Zalo are often overlooked), No → Zalo.
5. Has the user been active on Zalo in the last 7 days? Yes → Zalo, No → Email.

3 Checkpoints for Implementation

First, limit Zalo OA sending frequency to no more than 3 times per week to avoid being blocked by users. Second, keep email subject lines under 30 characters to prevent truncation on mobile devices. Third, provide unified unsubscribe or block options on both channels to respect user choices and reduce complaint risks.

In practice, you can start by sending a "reminder + summary" via Zalo, then include the full content in an email. For example: Zalo sends "You have a new bill of XXX. Click here for details," while the email includes the PDF bill and payment link. This way, you avoid being intrusive while ensuring complete information delivery.