Location: San Francisco, CA (preferred) Type: Full-Time Team: Engineering

Overview

At Blok, we’re building the simulation engine powering the next generation of adaptive software. Our multi-agent system predicts how different types of users will respond to digital experiences before any code is shipped. Product teams use Blok to simulate onboarding flows, test risky design changes, and de-risk product bets without waiting weeks for live traffic.

We’re hiring a Senior Full Stack Engineer to help us scale out our product. You’ll work across the stack - from backend systems that orchestrate multi-agent simulations to frontend interfaces that help teams visualize outcomes, compare variants, and turn insights into action.

🌍 Our Vision

Software today is static. We believe the future is adaptive interfaces that evolve in real time based on the user's behavior, intent, and context.

Blok is building the behavioral foundation model to power that shift - starting with a simulation engine that helps product teams understand, predict, and personalize user experience before launch. In the long term, we’re building toward a world where software feels more like a conversation than a fixed experience.

🔧 What You'll Be Doing

• Build and maintain features across our core web platform
• Develop tools that visualize agent behavior, including heatmaps, flow maps, and persona-level insights
• Collaborate closely with ML and infra teams to integrate LLM-driven agents, model outputs, and user simulations into the product
• Own internal tools and dashboards for analyzing agent performance, debugging simulations, and tracking cluster behavior
• Help shape UX for features like task authoring, experiment comparisons, and adaptive UI recommendations
• Work fast, ship weekly, and help define best practices as the product scales

✅ What We’re Looking For

• Have 5+ years of full stack experience, ideally in high-growth or startup environments
• Have strong product instincts—can build clean interfaces and ship usable features quickly
• Are comfortable owning systems end-to-end: from REST API to frontend state management
• Enjoy working with LLM outputs, AI behavior data, or simulation tooling
• Bonus: experience with data visualization (heatmaps, behavioral flows) or agent-based systems