She's worked at nearly every FAANG company. In her free time, she built a free tool to appeal health insurance denials.

• Holden Karau works in Big Tech during the day and builds her startup, Fight Health Insurance, at night.
• Karau said personal experiences with health insurance denials led her to create the platform.
• The platform uses AI and machine learning to streamline the insurance appeal process.

Holden Karau works as an open-source engineer in California — but just about every day after work, she's building Fight Health Insurance, a free AI-powered platform designed to help people appeal healthcare claim denials.

The 38-year-old Canadian has worked in the big data space for years, previously holding jobs at every FAANG company aside from Facebook.

Karau told Business Insider that while she had never worked on anything healthcare-related, her personal experiences with health insurance claim denials in the US led her to create an open-source tool to automate as much of the appeals process as possible.

Karau said that she's "seen different healthcare systems and the trade-offs," and the Canadian version isn't "perfect either." However, she grew increasingly frustrated with the US healthcare system while seeking out trans healthcare in California and recovering from a motorcycle crash.

Karau said denied claims lead to "a lot of suffering in the world today," and those challenges led her to start working on the AI project to help dispute health insurance denials.

"I'm not going to put up with this anymore. It's time to fight back," Karau said she told herself as she set out to build the tool. "And I think that's probably where the name came from."

She told BI that a later experience navigating her dog's pet insurance pushed her "over the edge" and made her determined to turn the proof of concept into a consumer product other people could use.

"I was like, I've had enough. This needs to not just be like a curiosity," Karau said. She wanted to "make it accessible to the average person," which factored into the decision to make it a free service.

Now, anyone in the US can generate an appeal with Fight Health Insurance by inserting some basic information, uploading a claim denial letter, and, if relevant, their plan documents.

The platform uses machine learning to identify and confirm details, and a fine-tuned large language model to pull data from PubMed, Karau said. The company uses an in-house AI tuned from a base model from Mistral AI, Karau said. To ensure patients' privacy, the system helps anonymize information by removing names and addresses.

Once the appeal is generated, users can review and edit it before mailing it off — or have the company fax it for $5. Karau said she added the faxing service after receiving emails from users saying they loved the platform but didn't have a printer and it was costly to get it printed somewhere else.

"It's a little weird working on an AI project and then going on to eBay to buy fax modems," Karau said. "But, hey, what is life if not a little weird?"

With insurers increasingly using AI to sift through claims, Karau said Fight Health Insurance offers a way to "level the AI playing field." She said while she wants doctors to make decisions about medications and diagnoses, she sees an opportunity for more AI tools to be used in the grunt work of dealing with insurance. Karau said AI could be useful in following up with patients after appointments, whether it be for reminders about surgery or to submit an out-of-network provider form.

The company now has two full-time staff and a few part-time contractors. Eventually, Karau said she plans to monetize the platform by building a professional version for hospital systems and medical vendors, who are also "feeling the pain from health insurance denials."

"Doctors are just super frustrated with all the time they spend dealing with insurance companies," Karau said.

Karau said that she plans to keep the consumer version free, aside from the $5 optional cost to have the company fax out an appeal.

"I think that it's really important that patients don't want to pay to use Fight Health Insurance because they already pay so much," Karau said.

Since launching the side project in August, Karau said over 1,000 have used the platform to help generate an appeal, and a handful have reached out to her to share success stories. She said just the other day she was talking to someone whose back surgery was successfully appealed using Fight Health Insurance.

"Now they're looking forward to getting back to riding motorcycles next year," Karau said.

Exactly how many of those appeals were successful isn't clear because users get responses directly from their health insurers rather than through the platform. The company also doesn't store user emails unless users opt-in, Karau said, so it currently doesn't have a way to follow up with people to learn the outcome unless they choose to share their contact information. However, she plans to incorporate replies from the platform in the future professional version to better track success stories.

In regard to recent conversations about the health insurance industry following the shooting of UnitedHealthcare CEO Brian Thompson, Karau said she understands the intensity of emotions surrounding what can sometimes be life-or-death treatment decisions made by insurance companies.

She also said there's been an increase in traffic to the Fight Health Insurance website in the wake of the larger discussion online about frustrations with the healthcare system in the US.

"I think consumers are hurting a lot in the health insurance space right now," Karau said.