Hey, I’m Stefan 👋

Right now I’m building Yap, a voice consumer app where you can talk with an LLM that sees your phone screen.
It can roast TikToks, analyze dating profiles, help you draft messages/emails and much more. Launch date TBD.

Some open-source infra experiments related to Yap:

• yap-kokoro-tts-api – deployment scripts & API for Kokoro TTS
• yap-kyutai-tts-api – deployment scripts & benchmark tests for Kyutai TTS (Moshi + 1.6B EN/FR model)
• yap-smart-turn-v2 - deployment scripts for a lightweight VAD model developed by Pipecat. Deprecated in favor of V3 that can run on CPU
• yap-vosk-stt-api - Vosk streaming ASR deployment with punctuation added via sherpa-onnx. Quality isn't great but it might be useful for someone dabbling in voice AI

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🧑‍🚀 Before Yap: RAI

A few years back I worked on RAI, a floating-peg stablecoin backed by ETH. RAI uses a PI controller to set its own funding rate (similar to a perp swap’s funding mechanism) and was my attempt at fulfilling the original vision for DAI. We scaled the system to $390M in user funds.

Repos from that era:

• geb – main code for RAI
• geb-rrfm-rate-setter – the redemption rate feedback mechanism (controller that sets the funding rate)
• geb-safe-saviours – adapters to deposit assets/wrapped tokens from other protocols into RAI-like systems. The deposited assets get auctioned to save CDPs from liquidation.

RAI was basically a super nerdy modified DAI fork.

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🎭 What I’ve been hacking on since

After crypto, I moved on to building consumer apps. Life’s too short to do boring ass B2B. A few highlights:

• llm-roleplay-webapp – think Character.ai x TikTok.

  • Used react-virtua for efficient chat virtualization
  • Related repos:
    • llm-inference-load-balancer – distribute inference requests across providers, scaling Llama models to 1000+ DAU
    • llm-roleplay-main-api – RAG + waitlist API
    • redis-user-waitlist – customizable Redis waitlist that actually scales

• yc-cofounder-matching-bot – a Selenium bot I built to automatically hunt for cofounders on YC’s Cofounder Matching platform.

  • Can change locations to search in different cities
  • Filters + saves founder profiles, sends them messages with your own templates
  • Uses GPT to decide if a profile is a fit or not
  • Sends you email reports with stats from each run
    (⚠️ Deprecated now due to YC’s security upgrades, but still a fun hack.)

• suno-music-discord-bot – generate music from images/videos inside Discord.
  (It scrapes Suno.com under the hood. Don’t tell them. 🙃)

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🌍 TL;DR

• Built RAI (floating-peg ETH-backed stablecoin w/ PI controller funding rate)
• Now building Yap (voice-first consumer AI app w/ screen awareness)
• In between: I worked a few years as project lead for a decentralized exchange that got to $1B+ in user funds. Decided to leave crypto at the end of 2023 and then started shipping a bunch of fun/weird consumer projects.

I love building products that are weird, unhinged and could not exist before LLMs came around. If you’re into that too, reach out and say hi 🤝