Software Engineer - Platform/Applied AI (YC)

An applied research lab is building data solutions for foundation model development, serving every frontier AI lab with a mission to deliver the best data to power the best models. Its work helps make expertise that once took a lifetime to build, available to everyone.

The team works directly with foundation model developers, shaping how their systems improve. Based in San Francisco, the company is backed by Altos Ventures, BoxGroup, Y Combinator, and angels from Google DeepMind, OpenAI, Anthropic, Meta Superintelligence Labs, and Microsoft AI. Forbes reported that it was raising at a $3.2 billion valuation.

Why Apply:

Massive Opportunity: Join a rapidly growing research lab working directly with frontier AI developers at a defining moment in the industry.

Founding Impact: Own and architect the core infrastructure powering the platform from the ground up.

Equity & Growth: Competitive salary and meaningful equity, with opportunities to shape the engineering organization and lead major technical initiatives.

Strong Team: Work alongside engineers and researchers with founding team experience from Citadel Securities, Meta, Google, Silver Lake, and Morgan Stanley.

Overview

As a core engineer and one of the company’s first hires, you’ll build data infrastructure shaping frontier model development. You’ll own entire projects end-to-end, take on significant responsibility, and see your impact immediately.

Responsibilities

• Build and scale complex data capture workflows across web (Next.js) and desktop (Python).
• Architect and optimize high-throughput data pipelines under heavy loads.
• Collaborate with the founding team on product strategy and ship features fast.
• Establish engineering best practices and foundations for team growth.

Required Qualifications

• Proficiency in JavaScript (Next.js) and Python, with experience building full-stack web applications.
• Experience with serverless architecture and cloud functions for heavy data processing on GCP/AWS.
• Hands-on experience with Redis (caching), Elasticsearch (indexing), and message queues (Kafka/RabbitMQ) for scalable, low-latency pipelines.
• Experience taking ideas into production; founder experience preferred.

Preferred Qualifications

• Background in AI research, LLM evaluations, or human-in-the-loop systems.

Company Benefits (For Eligible Employees)

• Medical, vision, and dental insurance
• 401(k) with employer match
• Daily UberEats meal stipend
• Monthly wellness stipend