Thunderbird is a popular free email client used by individuals and small businesses around the world. One of the most common questions users ask is whether it’s possible to create and send an HTML email Thunderbird. The short answer is yes — Thunderbird does allow you to use HTML templates. However, once you start designing and sending more professional messages, you’ll quickly run into limitations that make the process frustrating and time-consuming.
Can You Create HTML Email in Thunderbird?
Yes — Thunderbird does support HTML emails. You can import a custom template or even write your own code directly inside the editor. For users who just want to test a simple HTML email Thunderbird workflow, this can work fine. At first glance, it looks like Thunderbird could handle newsletters or business updates by using HTML templates. If you want to try it out yourself, follow our step-by-step guide on how to export HTML emails from Mail Designer 365.
In Thunderbird, you can choose the HTML option from the Insert menu to add custom code to your email.
Thunderbird allows you to paste custom HTML code into your message — but editing and formatting remain limited.
The Limitations of HTML Email Thunderbird
- Editing issues: Imported designs display distracting red lines, which makes it difficult to edit the template.
- Image problems: All images need to be reconnected manually, adding unnecessary extra work.
- Layout limitations: Backgrounds don’t extend to the full width of the email. Instead, white gaps appear at the top, left, and bottom, making your message look unfinished.
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Attachments or hosting: Every HTML email Thunderbird sends must either include attached images (making emails heavier) or rely on external hosting.
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- Imported HTML email templates in Thunderbird display distracting red outlines, making editing difficult.
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- Images often need to be manually reconnected when importing HTML templates into Thunderbird.
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- Sending your design without re-attaching there images will cause broken image placeholders after sending your HTML email with Thunderbird.
Why These Issues Matter for Your Business Emails
When sending out business communications, appearance and reliability matter. Using HTML email in Thunderbird may work for simple messages, but the limitations can cause real problems:
- Unprofessional look: Broken layouts, misaligned backgrounds, and missing images make your brand appear less trustworthy.
- Wasted time: Fixing every HTML email Thunderbird sends is inefficient.
- Inconsistent results: Emails that don’t render properly across devices risk confusing or frustrating your audience.
- Heavier emails: Thunderbird requires you to either attach all images to the message (making the email larger and more likely to hit spam filters) or host them externally, adding another layer of complexity.
- No performance insights: Without tracking, you can’t see who opened your email or what links they clicked.
The same HTML email sent with Thunderbird (left) shows formatting issues and requires image attachments, while Mail Designer 365 (right) delivers a clean, professional result.
A Better Alternative to Thunderbird HTML Email
- Design with ease: Drag-and-drop tools make it simple to create professional layouts without code.
- Send without issues: Emails go out exactly as designed, without red lines, broken images, or layout gaps.
- Use your contacts: Send messages directly to people in your Mac address book.
- Keep a record: BCC yourself automatically to track what was sent.
- Measure performance: Built-in tracking shows who opened your email and what they clicked.
With Mail Designer 365 Direct Mail, you can send professional HTML emails directly from your Mac — without broken layouts, missing images, or large attachments.
Conclusion
Creating and sending HTML email Thunderbird is technically possible, but the experience is far from smooth. From broken layouts to constant image reconnecting, Thunderbird’s limitations make it difficult to achieve a professional result.
If your goal is to send emails that look polished, work reliably across devices, and provide insights into performance, Thunderbird will quickly feel restrictive.
That’s where Mail Designer 365 comes in. With powerful design tools and the integrated Direct Mail function, you can create beautiful HTML emails and send them directly — without the headaches.
Try Mail Designer 365 today and experience a better way to design and send professional emails.