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Email Testing

Preview your email across devices, email clients, and light or dark mode before you send.

What Is Email Testing?

Email Testing lets you see exactly how your email will render across platforms. This helps you catch layout issues early. It also ensures your design looks consistent everywhere.

Email Testing shows how your email appears across:

  • Mobile devices

  • Desktop devices

  • Operating systems

  • Browsers

  • Email clients

  • Light Mode and Dark Mode

Demo Video

What Counts as a Test?

Each email client preview counts as one test.

Example:

  • You have 10 email clients configured.

  • You click Email Testing once.

  • 10 previews generate.

  • 10 tests are used.

Each preview:

  • Is rendered separately

  • Has its own loading status

  • Is tracked independently

If you want to know how many tests remain in your contract, contact your Customer Success Manager.

How to Access Email Testing

There are two ways to open Email Testing.

Option 1: From the Actions Menu (Top Right)

Use this method if you want to quickly run previews directly from the builder.

  1. Open your email in the builder.

  2. Click the Actions menu in the top right corner.

  3. Click Email Testing.

Actions menu expanded with email testing option highlighted.

Option 2: From Preview Mode (Bottom Right)

Use this method if you want to review your email first.

  1. Open your email in the builder.

  2. Click Preview in the bottom right corner.

  3. Click the Test Email tab.

Opening the email preview in the email builder and switching to the Test Email view.

Review Your Email Previews

  1. Wait for previews to load.

  2. Click any thumbnail to open a full preview.

    Email previews for different email clients.

  3. Click Refresh Previews

  4. Filter by Device

  5. Filter by Light Mode or Dark Mode

Preview in light or dark mode on both devices

Navigate Between Tests

  • Select another thumbnail from the right panel.

  • Click the blue X to exit the email client and return to grid view.

  • Click the Back to Editor button in the top-left corner to return to the builder.

Navigating between different email test

Role Permissions

You can control who can generate previews. This helps manage test usage.

Allow Non-Admins to Generate Previews

  1. Go to Admin.

  2. Click Roles.

  3. Select the role you want to update.

  4. Enable Can generate email client previews.

  5. Click Save.

Email Preview role permissions

Customize Email Clients (Admins Only)

You can control which clients are available for testing.

Add or Remove Email Clients

  1. Go to Admin.

  2. Click Settings.

  3. Scroll to Email Testing.

  4. Click Customize Email Clients.

    Customize email client button under the email testing settings section.

  5. Click the + icon to add a client.

  6. Click the X to remove a client.

  7. Click Save.

Clients Available

Desktop

  • Apple Mail — Dark — macOS 13

  • Apple Mail — macOS 13

  • Outlook 365 — macOS 13

  • Outlook 365 — Dark — macOS 13

  • Outlook 2021 — Windows 2022 — 120 DPI

  • Outlook 2021 — Dark — Windows 2022 — 120 DPI

  • Outlook 2019 — Windows 2022

  • Outlook 2019 — Windows 2022 — 120 DPI

  • Outlook 2021 — Windows 2022

  • Outlook 2021 — Dark — Windows 2022

  • Outlook 365 — Windows 2022

  • Outlook 365 — Dark — Windows 2022

  • Outlook 365 — Dark — Windows 2022 — 120 DPI

  • Outlook 365 — Windows 2022 — 120 DPI

Mobile & iPad

  • Gmail — Android 14 — Pixel 7

  • Gmail — Dark — Android 14 — Pixel 7

  • Gmail — Dark — Android 14 — Pixel 8

  • Gmail — Android 14 — Pixel 8

  • Gmail — Dark — Android 14 — Pixel 8 Pro

  • Gmail — Android 14 — Pixel 8 Pro

  • Gmail — Dark — Android 15 — Galaxy S24 Ultra

  • Gmail — Android 15 — Galaxy S24 Ultra

  • Gmail — Android 15 — Galaxy S25 Ultra

  • Outlook — Android 14 — Pixel 7

  • Outlook — Dark — Android 14 — Pixel 7

  • Outlook — Android 14 — Pixel 8

  • Outlook — Dark — Android 14 — Pixel 8

  • Outlook — Android 14 — Pixel 8 Pro

  • Outlook — Dark — Android 14 — Pixel 8 Pro

  • Outlook — Android 15 — Galaxy S24 Ultra

  • Outlook — Dark — Android 15 — Galaxy S24 Ultra

  • Outlook — Android 15 — Galaxy S25 Ultra

  • Outlook — Dark — Android 15 — Galaxy S25 Ultra

  • Outlook — iOS 17 — iPhone 14

  • Outlook — Dark — iOS 17 — iPhone 14

  • Outlook — iOS 17 — iPhone 15

  • Outlook — Dark — iOS 17 — iPhone 15

  • Outlook — iOS 18 — iPhone 16

  • Outlook — Dark — iOS 18 — iPhone 16

  • Apple Mail — iOS 18 — iPhone 11

  • Apple Mail — Dark — iOS 18 — iPhone 11

  • Apple Mail — iOS 18 — iPhone 12

  • Apple Mail — Dark — iOS 18 — iPhone 12

  • Apple Mail — iOS 18 — iPhone 12 Mini

  • Apple Mail — Dark — iOS 18 — iPhone 12 Mini

  • Apple Mail — iOS 18 — iPhone 13

  • Apple Mail — Dark — iOS 18 — iPhone 13

  • Apple Mail — iOS 18 — iPhone 13 Mini

  • Apple Mail — iOS 18 — iPhone 14

  • Apple Mail — Dark — iOS 18 — iPhone 14

  • Apple Mail — iOS 18 — iPhone 14 Pro

  • Apple Mail — iOS 18 — iPhone 14 Pro Max

  • Apple Mail — Dark — iOS 18 — iPhone 14 Pro Max

  • Apple Mail — iOS 18 — iPhone 15

  • Apple Mail — Dark — iOS 18 — iPhone 15

  • Apple Mail — iOS 18 — iPhone 15 Pro

  • Apple Mail — iOS 18 — iPhone 15 Pro Max

  • Apple Mail — Dark — iOS 18 — iPhone 15 Pro Max

  • Apple Mail — iOS 18 — iPhone 16

  • Apple Mail — Dark — iOS 18 — iPhone 16

  • Apple Mail — iOS 18 — iPhone 16 Pro

  • Apple Mail — iOS 18 — iPhone 16 Pro Max

  • Apple Mail — Dark — iOS 18 — iPhone 16 Pro Max

  • Apple Mail — iOS 18 — iPhone 11 Pro

  • Apple Mail — Dark — iOS 18 — iPhone 11 Pro

  • Apple Mail — iOS 18 — iPhone 11 Pro Max

  • Apple Mail — iOS 18 — iPhone 12 Pro

  • Apple Mail — iOS 18 — iPhone 12 Pro Max

  • Apple Mail — Dark — iOS 18 — iPhone 12 Pro Max

  • Apple Mail — iOS 18 — iPhone 13 Pro

  • Apple Mail — iOS 18 — iPhone 13 Pro Max

  • Apple Mail — Dark — iOS 18 — iPhone 13 Pro Max

  • Apple Mail — iOS 18 — iPhone 14 Plus

  • Apple Mail — iOS 18 — iPhone 15 Plus

  • Apple Mail — iOS 18 — iPhone 16 Plus

  • Apple Mail — iOS 18 — iPhone SE (2nd Gen)

  • Apple Mail — iOS 18 — iPhone SE (3rd Gen)

  • Apple Mail — iOS 18 — iPhone XR

  • Apple Mail — iOS 18 — iPhone XS

  • Apple Mail — iOS 18 — iPhone XS Max

  • Gmail — Dark — iOS 18 — iPhone 16

  • Gmail — iOS 18 — iPhone 16

  • Gmail — Dark — iOS 17 — iPhone 15

  • Gmail — iOS 17 — iPhone 15

  • Gmail — Dark — iOS 17 — iPhone 14

  • Gmail — iOS 17 — iPhone 14

  • Apple Mail — iOS 18 — iPad Pro 12.9-inch (6th Gen)

  • Apple Mail — iOS 18 — iPad Pro 11-inch (4th Gen)

  • Apple Mail — Dark — iOS 18 — iPad (10th Gen)

  • Apple Mail — iOS 18 — iPad Air (5th Gen)

  • Gmail — AI — iOS 18 — iPhone 16

  • Apple Mail — AI — iOS 18 — iPhone 16

Webmail

  • AOL Webmail — Chrome — macOS 13

  • AOL Webmail — Edge — macOS 13

  • AOL Webmail — Firefox — macOS 13

  • Gmail Webmail — Chrome — macOS 13

  • Gmail Webmail — Firefox — macOS 13

  • Gmail Webmail — Edge — macOS 13

  • Outlook Webmail — Chrome — macOS 13

  • Outlook Webmail — Dark — Chrome — macOS 13

  • Outlook Webmail — Edge — macOS 13

  • Outlook Webmail — Firefox — macOS 13

  • Yahoo Webmail — Chrome — macOS 13

  • Yahoo Webmail — Firefox — macOS 13

  • Yahoo Webmail — Edge — macOS 13

Best Practices for Accurate Previews

Large images can affect preview accuracy.

The preview tool captures screenshots quickly. If an image loads slowly, it may not appear in the preview. The live email may still display correctly.

Image Guidelines

  • Keep images under 1MB

  • Export images at 2x the display width

    • Example: If image displays at 600px, export at 1200px

  • Keep GIF file sizes smaller

  • Avoid oversized GIFs in Outlook

These steps improve rendering consistency across clients.

Frequently Asked Questions

Why Don’t Token Placeholder Values Appear in Email Testing?

Email Testing uses the same HTML as Download as HTML. It does not render placeholder tokens from your Marketing Automation Platform (MAP). A Marketing Automation Platform (MAP) is the system that sends your emails and replaces tokens with real data.

To confirm your tokens work:

  1. Export the email.

  2. Preview it inside your MAP.

  3. Confirm tokens populate correctly.

Need more help? Contact support via live chat using the chat bubble in the bottom right corner or email support@knak.com.

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