This is a submission for the Postmark Challenge: Inbox Innovators.

What I Built

SignAI is a minimal, AI-powered service that generates clean, professional email signatures — just by sending an email.

No forms. No UI. Just email.

Users can send their contact info and preferences to a dedicated Postmark Inbound address, and receive a responsive, GPT-generated HTML signature in return.

It’s a fun, developer-focused take on signature generation — great for personal branding or team-wide consistency.

Demo

📬 Try it yourself!
Send an email to:
a274c047ed8bf5fe0171766e9e428d3a@inbound.postmarkapp.com

Example Email Body:

Name: Emanuele Bartolesi
Role: Senior Cloud Engineer at Xebia
Website: https://emanuelebartolesi.com
LinkedIn: /in/kasuken
GitHub: https://github.com/kasuken
Phone: +41 23 3214 43
Pronouns: he/him
Style: Minimalist, monochrome

🔁 Within seconds, you’ll get a reply email with:

  • ✨ A ready-to-copy HTML signature
  • 🖼️ A rendered inline preview
  • 📅 (Optional) a download link or vCard

Here’s a preview of a signature created by the bot:

Image description

Note: Use any dummy data — no backend validation is enforced during this challenge demo.

Code Repository

{% embed https://github.com/kasuken/SignAI %}

How I Built It

This project is powered by a modern cloud-native stack:

Function Tech
Email handling Postmark Inbound Webhooks
AI generation Azure OpenAI (GPT-4)
Backend/API Azure Functions in C#
Infrastructure Azure App Service + Azure Storage
Dev tools GitHub Copilot, VS Code, Visual Studio, JetBrains Rider

The Process

  1. Inbound Email Parsing
    Postmark handles incoming emails and routes them to an Azure Function via webhook.

  2. Prompt Engineering
    A carefully crafted system prompt ensures the model outputs minimal, inline-styled, accessible HTML using user preferences.

  3. Response Generation
    Azure OpenAI generates the signature, which is emailed back using Postmark Outbound.

  4. No UI Needed
    Everything is done via email — a playful constraint that led to a surprisingly intuitive UX.

This was a solo project built for fun, fast prototyping, and Postmark exploration.
Feel free to clone, fork, or contribute ideas!

Thanks for checking out SignAI and the Postmark Challenge! 📬

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