Aum Upadhyay

Aum Upadhyay and co-founder Eduardo Velasco became whitehat hackers after leaving Amazon, and "hacked OpenAI, Anthropic, Google, and Microsoft 15 times in two weeks," they wrote in Silmaril's YC launch. "We saw firsthand how far ahead attackers already are. That's why we built Silmaril." Upadhyay is co-founder and CEO.

Security Work at AWS

Upadhyay built the security and privacy framework at AWS that prevented over $1.8B in damages, he wrote on Silmaril's YC page. Velasco, Silmaril's CTO, is an ex-Amazon tech lead who specialized in low-latency ML models.

Founding Silmaril

Silmaril is a self-healing prompt injection defense for AI applications and agents. Customers plug it into frameworks like LangGraph with 5 lines of code, and its latency overhead is 20ms. Silmaril says it has stopped $28M of damages for customers.

Silmaril's Approach to Agent Safety

Because Silmaril reasons over application snapshots instead of input patterns, it catches contextual and multi-turn attacks that single-input classifiers miss, according to the launch post. Autonomous agents also probe each customer's application to find and verify attack chains such as data exfiltration and privilege escalation.