Substrate

What do they actually do

Substrate provides software that logs into payer portals and practice systems to do the repetitive click-work of medical billing. It checks claim status, submits appeals with medical-record attachments, posts payments/refunds, and triages A/R worklists so human billers only handle exceptions. The system records what it did with auditable logs and artifacts (including printable records and portal run traces) and is built to run the same way each time across many EMRs/practice systems (Substrate site, product pages).

Today it’s used by healthcare practices and outsourced/managed billing teams across specialties, with a focus on high‑volume billing operations. The company reports processing more than $40M in monthly claims volume, advertising time savings per claim and improved appeal outcomes from a hands‑free medical‑records appeals agent (Substrate site, YC profile, LinkedIn).

Near‑term work focuses on broadening payer/EMR coverage and strengthening exception handling with a “deep research” agent built for credentialed, multi‑source investigation, while maintaining deterministic, auditable write operations for regulated workflows (founder writing, product pages).

Who are their target customer(s)

• In‑house billing teams at medium-to-large practices (urgent care, oncology, orthopedics, behavioral health): Staff spend hours in payer portals checking status, uploading records, and pushing appeals, creating backlogs and slower cash flow. They need repeatable automation that works across their EMR and payers (product pages, YC profile).
• Outsourced/managed billing companies handling many provider clients: Scaling across dozens of portals and EMRs forces constant hiring/training and leads to inconsistent work. They want standardized, auditable automation that reduces manual clicks and error rates (product pages, LinkedIn).
• Small specialty practices with lean billing staff: Small teams get overwhelmed by denials, records requests, and appeals, causing missed recoveries and diversion from patient care. Automating document pulls and appeal submissions eases the load and speeds reimbursement (product pages).
• Revenue‑cycle leaders at hospitals or health systems: They need predictable, auditable automation; unsafe or inconsistent write actions into payer/EMR systems create compliance and financial risk. Deterministic agent behavior and audit trails address governance at scale (founder writing, product pages).
• Medical‑records and appeals specialists inside billing teams: Collecting, validating, and attaching clinical records for appeals is time‑consuming and limits throughput and win rates. A hands‑free appeals agent can raise throughput and recoveries while reducing manual effort (product pages, LinkedIn).

How would they acquire their first 10, 50, and 100 customers

• First 10: Run founder‑led pilots with high‑volume in‑house teams and managed billers, map their workflows, run agents on a small queue, and quantify time saved and dollars recovered; convert pilots to contracts with audit‑trail documentation and a short paid pilot path (product pages, YC profile).
• First 50: Leverage early case studies and references for targeted outbound to similar specialties and via managed‑billing partners; build an onboarding playbook and a small integrations bundle for common EMRs/portals to reduce deployment time (product pages).
• First 100: Add channel/partner sales and customer success to enforce safe, auditable write operations and exception runbooks; offer volume pricing for managed‑billing firms, plus self‑serve trial options for small practices, supported by ROI/audit‑trail demos (founder writing, product pages).

What is the rough total addressable market

Top-down context:

U.S. revenue‑cycle management (RCM) software and services are estimated at roughly $58B in 2024, representing the broad spend Substrate can sell into across providers and billing firms (MarketsandMarkets).

Bottom-up calculation:

A labor‑based view of the workflows Substrate automates: ~430k billing/posting clerks at ~$47k mean wage (~$20B) plus ~186k medical‑records specialists at ~$54k (~$10B) implies roughly $30B/year of payroll tied to claims/denials work (BLS clerks, BLS records specialists).

Assumptions:

• Focus is U.S. market and roles closely tied to claims status, denials, records requests, and appeals.
• A meaningful portion of these roles’ tasks are automatable with portal/EMR automation and auditable workflows.
• Buyers will share a fraction of realized labor savings as software/transaction spend.

Who are some of their notable competitors

• Notable: Automation platform for healthcare operations, including revenue‑cycle tasks; executes portal workflows and data entry for providers.
• AKASA: AI‑driven automation for health‑system revenue cycles, focused on claims, denials, and other back‑office workflows with human‑in‑the‑loop support.
• Waystar: Large RCM software platform offering claims management, denials management, and payment solutions; a common incumbent in provider billing stacks.
• R1 RCM: Full‑service revenue‑cycle outsourcing for hospitals and physician groups; competes where buyers prefer managed services that embed automation.
• Infinitus: Voice agents that call payers for prior auth and claim status, reducing phone‑based tasks adjacent to Substrate’s portal automation focus.