I Built an AI Tool to Fix Outlook Email Compatibility Issues (Here's How)

Fei Zhang — Wed, 08 Apr 2026 13:49:34 +0000

If you've ever tried to create HTML emails, you know the pain. What looks perfect in Gmail falls apart in Outlook 2016. Flexbox? Grid? CSS variables? Forget about it. We're still coding like it's 1999.

The Problem

Last month, I spent 2 hours debugging a simple promotional email. ChatGPT gave me clean, modern HTML. It looked great in Chrome, fine in Gmail, and completely broken in Outlook.

The issues?

Divs don't render consistently
Flexbox is a no-go
CSS variables aren't supported
Outlook has its own special "features"

I needed table-based layouts, inline CSS, and conditional comments. Writing that by hand feels like time travel to the

The Secret Sauce: Prompt Engineering

The magic isn't in the model—it's in the constraints:

You are an expert email HTML developer.

CRITICAL RULES:
1. Use <table> layout only. NO <div> for structure.
2. All CSS must be inline (style="..."). NO <style> tags.
3. NO Flexbox, Grid, or CSS variables.
4. Images must have width/height and alt attributes.
5. Buttons must be table-based for Outlook compatibility.
6. Max-width: 600px for desktop consistency.
7. Include Outlook conditional comments where needed.

OUTPUT: Complete HTML email code only. No explanations.

Real Results

Before:

2 hours manual coding
30 minutes testing in Litmus
Still finding Outlook bugs

After:

30 seconds to generate
5 minutes to customize
Works in all major clients

Try It Yourself

🚀 Live Demo

Current features:

5 email types (Welcome, Promotional, Newsletter, Transactional, Event)
Natural language input
Live preview
One-click HTML copy

It's free — I'm validating whether this solves a real problem.

What's Next?

If people find this useful, I'm planning:

Custom brand colors/logos
Export to Mailchimp/HubSpot
Litmus/Email on Acid integration
Template library

The Bigger Picture

Email HTML is a perfect example of AI doing what humans hate. Nobody wants to write table-based layouts in 2025. But millions of emails are sent every day, and they need to work everywhere.

AI won't replace email developers. But it can handle the boilerplate, letting humans focus on strategy and design.

What do you think? Would you use something like this? What features would make it actually valuable for your workflow?

Drop a comment — I'm building this in public and need real feedback.

*P.S. If you're an email developer, I'd love your brutal honesty. Does this help, or am I solving the wrong problem?*GeoCities era.

The Solution

So I built an AI tool that generates email-client-compatible HTML from plain English descriptions.

Example input:

A welcome email with a header image, personalized greeting, 
3 feature bullets, and a primary CTA button in brand blue

What it generates:

Table-based layout (yes, really)
Inline CSS only
Outlook conditional comments
Mobile-responsive structure
Image fallbacks

The Tech Stack

AI Model: OpenAI GPT-4o-mini

Cost: ~$0.003 per email (basically free)
Speed: ~3 seconds generation time
Quality: Excellent for structured HTML

Why GPT-4o-mini?

Cost-effective for high-volume use
Great at following strict formatting rules
Fast enough for real-time use

Frontend: Next.js 14 + Tailwind CSS + shadcn/ui
Deployment: Vercel (free tier)
Code: GitHub Repository

DEV Community: Fei Zhang