I built a VS Code extension to preview Jinja2 templates in REAL-TIME (and it runs real Python!)

[Keshav-Madhav]

Hey Git,

I've been grinding on this for a while and it's finally OUT!!!

It’s a VS Code extension called Live Jinja Renderer. It's designed to kill that awful "save, switch, run, check, repeat" loop we all go through when writing templates.

Here are the links upfront:

• VS Code Marketplace: https://marketplace.visualstudio.com/items?itemName=KilloWatts.live-jinja-renderer
• GitHub (Source Code): https://github.com/Keshav-Madhav/live-jinja-renderer
• Open VSX (for VSCodium): [https://open-vsx.org/extension/KilloWatts.live-jinja-renderer](https://www.google.com/search?q=https://open-vsx.org/extension/KilloWatts.live-jinja-renderer)
• Companion Site: https://keshav-madhav.github.io/live_jinja/

What My Project Does

It gives you a live-preview panel inside VS Code that shows your rendered Jinja2 template... as you type.

It's got all the stuff I wanted for my own workflow:

• ⚡ Instant live preview of the rendered HTML or text.
• ✏️ A panel where you can type your variables in JSON and watch the template update.
• 🔥 Clickable error messages (my favorite!) that jump right to the broken line in your template.
• 📊 Supports Markdown & Mermaid diagram rendering from the output.
• 🧹 Smart whitespace handling.

Target Audience

Basically, anyone who writes Jinja templates in VS Code and is tired of guessing the output.

• DevOps Engineers: Working with Ansible, Salt, or other config management.
• Python Web Devs: Using Flask, Django (with Jinja), or FastAPI.
• Data Engineers: Anyone using dbt for their SQL templating.
• AI/ML Folks: Writing complex, templated prompts.

It's intended to be a robust, daily-driver tool, not just a toy project.

Comparison (Why this is different)

This is the main part: No fake JS ports.

Most other "Jinja" previewers I've found are just JavaScript-based simulators. They don't support the full Jinja syntax, custom filters, or Python logic, so the preview is just an approximation.

My extension runs real Python Jinja2 inside VS Code using Pyodide.

This means what you see in the preview panel is exactly what you will get in your production Python environment. It's an actual interpreter, not a simulator.

Jinja is everywhere now and I was sick of the broken workflow. So I built this to fix it.

Go try it out and tell me what breaks. 😂 PRs are welcome!