Silicon Valley developer Sigil Wen has introduced Underdog, an invite-only beta for an AI assistant designed around user privacy. The model runs entirely on-device, meaning user data remains on hardware they already own, such as Macs and Windows PCs, with support for Linux, iPhone, and Android arriving soon. Wen, a Thiel Fellow who spent his youth coding alongside prominent AI figures like Andrej Karpathy and Perplexity founder Aravind Srinivas, built Underdog to prove that users do not need to sacrifice personal security for powerful AI capabilities.
Background and Early Coding Roots
Before launching Underdog, Wen spent his formative years in Silicon Valley living in an AI hacker house. He tested early versions of industry-shaping technologies, including the chatbot that became Claude, an early image generator that evolved into Midjourney, and early iterations of GPT-3 and Stable Diffusion. He even figured out how to run GPT-2 on an Apple Watch for fun. Naval Ravikant previously hired him for Airchat, and he is now backed by prominent names across the technology sector.
Husky Inference Engine and Privacy Features
Underdog operates on Husky, an inference engine built by Wen to execute AI models efficiently on local hardware. The engine moves less data between a computer's main processor and its graphics chip compared to rival systems. Additionally, the assistant includes security features such as encrypting credentials for emails and linked accounts. Underdog relies on a 27-billion parameter reasoning model fine-tuned from Qwen3.8-27B, which Wen argues performs favorably against older top-tier models in specific benchmarks while handling everyday tasks like math homework and shopping research.
Unique Business Model and High-Profile Backing
Unlike traditional AI providers that host massive data centers and rely on user data collection or subscriptions, Underdog is free and ad-free. Because computation happens locally, server overhead costs are eliminated. Instead, backed by Stripe co-founder Patrick Collison, Underdog takes a small percentage from payment transactions processed through Stripe's secure rails. Conway Research, the startup behind the product, is backed by Andreessen Horowitz, Khosla Ventures, Hummingbird, SV Angel, the Anthology Fund, and notable angel investors including prominent angel investors like Guillermo Rauch, Noam Brown, and Deedy Das.
