After months of iteration, I finally feel ready to share ReplyFox

Hey everyone,

I’ve been building something on evenings and weekends called ReplyFox — an AI service that automatically replies to comments under Instagram posts in your brand’s tone.

For a while I didn’t feel comfortable showing it because it wasn’t solid enough. Now it finally works end to end, and I think it’s worth sharing.

What it does

When you sign up with your Instagram business account, ReplyFox automatically pulls your posts, captions, and bio. It builds a profile context from that data — no manual setup required. Using this context, it generates replies to comments and can either post them automatically or let you review them first.

Tech stack

The backend is written in Python (FastAPI) with async task handling via ARQ + Redis. For contextual replies, it uses a RAG pipeline with OpenAI embeddings stored in Qdrant. The challenging part was designing the auto-profile builder to extract meaning and tone from social content in a consistent way.

Why I built it

A lot of small business pages lose engagement simply because they can’t keep up with comment replies. Most automation tools sound robotic. I wanted to see if AI could handle that job in a natural, brand-aligned way.

Current state
• Live at https://replyfox.io
• Profile auto-build is working
• Logs for every AI-generated reply
• Auto-post toggle for manual review vs. full automation

Next on the list: analytics and tone adjustment controls.

If you’ve built something in the AI + social space, or just want to discuss architecture or growth, I’d love feedback.