How I Built a Contract Automation Platform with ASP.NET, Angular, and Dynamic .docx Templates

When I started building Contractize.app, my goal was simple: let people create clean, accurate contracts in seconds — without legal friction.

But making that work under the hood? That was the fun part.

In this post, I’ll share how I built the backend with ASP.NET, the frontend with Angular, and integrated external document rendering through .docx templates and Formize API to generate final PDFs — all with automation in mind.

🛠️ Tech Stack Overview

• Frontend: Angular
• Backend: ASP.NET Core
• Document Templates: Microsoft Word .docx files
• API Integration: Formize.com (for template filling & PDF generation)
• Output: Publicly accessible PDF contracts

📄 Why .docx?

Instead of hardcoding templates or using plain-text, I chose .docx because:

• It's familiar to end users (Word format = comfort).
• It supports rich formatting (tables, styles, variables).
• It's editable by non-tech staff (lawyers, ops, etc.).

Templates were uploaded to a central storage on Formize.com, where variable placeholders like {{clientName}} or {{startDate}} were pre-defined.

🔌 API Flow: Dynamic Contract Generation

Here's the high-level flow of how dynamic contract creation works:

1. User fills a form on the frontend (Angular).
2. Data is sent to ASP.NET backend.
3. Backend compiles a JSON object with the correct variables.

4. A POST request is made to Formize API:
   

   {
     "templateId": "nda-template.docx",
     "data": {
       "clientName": "Acme Corp",
       "startDate": "2025-05-27",
       ...
     }
   }
   

5. Formize fills the .docx template and returns a PDF download link.

6. The backend saves that link, sends it to the frontend, and optionally emails it to the client.

⚡ The result? A professional, filled, legally structured contract in under 5 seconds.

🚀 Lessons Learned

• Using .docx was a game-changer: Legal teams can update templates without touching code.
• ASP.NET + Angular combo was seamless, especially for form validation and API integration.
• Formize API saved weeks of work by abstracting template parsing and PDF generation.
• Caching document links (or PDFs themselves) is key for performance if users generate many contracts in a session.

📚 Next Steps

We're now expanding to:

• Dynamic clause toggles (e.g. include/exclude arbitration).
• Multi-language templates.
• eSignatures (integrating DocuSign or HelloSign).

If you're building anything document-related, or want to automate contracts for your team or startup — feel free to ping me or check out Contractize.app. Happy to share more behind-the-scenes!

💬 Have you ever built a doc-generation flow? Used .docx in production? Would love to hear your setup.