Emojis can help your email stand out in a busy inbox, making subject lines more eye-catching and adding a friendly human touch. But they also render differently across email clients, devices, and operating systems. Not all of your customers will see the same emoji the same way, and some may not see emojis at all.

This guide explains how emojis work in emails, which devices support them, how they appear in different clients, and how to use emojis safely in Omnisend without harming your deliverability.

Emojis can be a useful tool for creating a more engaging experience for your contacts. They can:

However, emojis can appear differently depending on the device, operating system, browser, or email client your contacts use. Even though emojis are based on Unicode (for example, 😉 corresponds to U+1F609), each platform, such as Apple, Google, Microsoft, Samsung, and others, draws its own version. This means the same emoji can look slightly different, or sometimes very different, for each email recipient. Some older devices or email clients may not support certain emojis at all, showing them as empty squares □ or fallback symbols.

Because of these differences, it’s important to understand how emojis behave across various environments before using them in your campaigns or automations.

Emojis can be used in both your subject line and the email body, but they don’t always behave the same way.

Subject lines are rendered by inbox interfaces (like Gmail’s inbox or Outlook’s message list), while emojis in the email body are rendered by the email client’s HTML engine. Because these areas use different font sizes and rendering rules, the same emoji may appear slightly different, especially in size.

For example, in Gmail, emoji size in the subject line is fixed, but in the email body, it adjusts based on the text size you set in the Omnisend Email Builder.

In Campaigns, you’ll find the emoji picker in the Email Settings step, directly within the Subject line field.

In Automations, click on the email you want to edit and locate the Emoji picker in the right-side menu, inside the Subject line field.

Emojis render differently depending on three factors:

Emojis can appear differently depending on the operating system your subscribers use, since each system includes its own emoji font and design style. While the same Unicode character defines every emoji, the visual interpretation varies between Apple (iOS & macOS), Android, and Windows. As a result, the same emoji may look more rounded, flat, colorful, or simplified depending on the device.

The way your emails display emojis also depends on the email client your subscribers use to read your message. Even on the same device or operating system, email clients apply their own rendering rules, fallback fonts, and display behaviors. This means emojis can appear slightly different in Gmail, Apple Mail, Outlook, and other inbox environments.

For instance, the nail polish emoji shows as red in Gmail but purple in Outlook (both opened on Google Chrome). So if you're promoting a red nail polish using that emoji, some subscribers may actually see a purple version instead.

Emoji appearance can also vary depending on whether your contacts open your email on a mobile device or a desktop computer. Even when two devices use the same operating system or email client, mobile and desktop environments can still interpret and display emojis differently.

Here are a few examples from the latest 2025 versions of Apple (iOS), Samsung, Microsoft (Windows 11), and Huawei:

While emojis themselves don’t automatically trigger spam filters, how you use them can influence deliverability:

Preview your email on multiple devices (iOS, Android, Windows, macOS) and in multiple email clients (Gmail, Apple Mail, Outlook). This helps you catch unexpected rendering differences before the final email lands in your customers' inboxes.

Test subject lines with and without emojis or try different emojis to see which option your audience responds to best.

Choose simple, common emojis that are supported across most devices and email clients. These are less likely to appear distorted, outdated, or replaced with fallback symbols. Emojis like 🙂 😊 😉 ❤️ ⭐️ ✨ ✔️ 🎁 🔔 🔥 tend to display clearly and consistently.

Emojis themselves don't trigger spam filters by overusing them (3+ per subject line) or pairing them with spammy words (e.g.,🚨 URGENT) can.

Why does my emoji show as a □ box?

This happens when the recipient's device or email client doesn't support that emoji. To avoid this, we recommend sticking to widely recognizable emojis and testing your email on different devices and email clients.

Yes, but use them sparingly. Transactional emails, such as order confirmation, should prioritize clarity. Emojis can add a friendly tone, but they should not distract from or replace key content.