Substrate AI Seeks Harness Engineer to Build Healthcare RCM Automation

Substrate, a Y Combinator S24 startup building AI-native business process outsourcing for healthcare revenue cycle management, is seeking a Harness Engineer to join their team in San Francisco. The company is developing browser-based AI agents that automate claims processing, payment reconciliation, and other tedious healthcare administrative tasks.

The Opportunity

Substrate is tackling the $14 billion outpatient revenue cycle management market by building what they call "the world's first AI native BPO." Their platform already processes over 500,000 healthcare claims monthly, helping physician groups, EMR providers, and BPOs accelerate accounts receivable and get reimbursed more quickly and cost-effectively.

The Harness Engineer role is critical to advancing Substrate's AI systems that are already in production. The position involves building and extending AI agents that can understand complex healthcare contracts, read EDI companion guides, navigate sensitive healthcare and financial infrastructure, and make intelligent decisions about claims processing.

What You'll Build

As a Harness Engineer at Substrate, you'll work on several key areas:

• Agent Development: Design and build AI agents capable of monitoring claims, reviewing payer policies, determining medical necessity, iterating through messy provider data, and reconciling payments
• Deployment Infrastructure: Partner with clients to safely deploy agents in extremely sensitive healthcare environments
• Measurement Systems: Improve how the company measures and tracks agent and model behavior, increasing precision while optimizing speed and cost across tens of millions of claims annually
• Adaptive Workflows: Explore how work gets done as individuals gain more leverage through AI tools, focusing on effectiveness and efficiency

The Ideal Candidate

Substrate is looking for someone who has been "load bearing" in previous roles and is willing to take extreme ownership. The ideal candidate should have:

• Deep experience with modern LLM architectures, fine-tuning approaches, and large-scale evals
• A track record of independently building and shipping ML/AI products that solve real business problems
• Either healthcare domain knowledge or excitement about using AI to automate healthcare tedium
• Experience starting companies, launching independent products, or being an early startup engineer
• Proficiency as a traditional software engineer who has fully adopted coding agents into their workflow
• Interest in working in-person in San Francisco three days per week

Interview Process

Substrate's interview process is designed to evaluate both traditional coding abilities and AI-assisted development skills. Candidates will:

1. Present something they've built, explaining the prompts used and why they chose that particular problem
2. Complete a technical interview with both pure technical and AI-assisted components
3. Demonstrate their ability to write and review code, as well as their adoption of AI technologies in their coding practice

The company emphasizes that candidates should show results and explain their problem-solving approach, whether the work was done entirely by hand or with AI assistance.

Company Background

Substrate was founded in 2024 by Ayo Omojola and Inderpal Singh. The team brings deep expertise in healthcare, AI, and full-stack engineering, with multiple startups under their belts and extensive networks in the healthcare industry to help bootstrap initial customers and revenue.

Their mission is to augment and replace employees in healthcare RCM rather than replace existing software, with the ultimate goal of helping providers get paid fairly. The company is positioned to disrupt the traditional BPO model by leveraging AI agents that can handle complex, nuanced tasks that previously required human intervention.

Compensation and Location

The role offers a salary range of $140,000 to $200,000 plus 0.01% to 0.10% equity. The position is based in San Francisco with a hybrid schedule requiring three days per week in the office.

For candidates interested in applying, Substrate requests that applicants show something they've built and be prepared to discuss their development process, including the use of AI tools and the reasoning behind their problem selection.

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