How Propeller Industries saves time for over 200 clients with the BILL API Platform

“We're seeing a 40% efficiency gain. That's not incremental. That's massive.”

Todd Rebner knows what accounts payable looks like at scale. As Chief AI Officer at Propeller Industries, he leads the firm's automation strategy by building the systems that allow 250 people to manage financial operations for more than 300 venture-stage and high-growth startups. This includes companies that from those cashing their first pre-seed check to decacorns.

When Rebner joined Propeller in 2025, he started auditing every workflow. "We looked at all of our processes and said: which ones make sense, which ones are duplicative, which ones are just overly verbose," he explains. The rationalization led him to the BILL API Platform.

Today, the custom integration Propeller built on the BILL API Platform processes invoices automatically at 5 AM by sorting, coding, matching vendor history, and flagging anomalies before the team's first sip of coffee. The result includes 40% efficiency gains* and 15% fewer errors* across their AP practice.

‍Zero standardization across 300+ clients

One of the biggest tasks at Propeller is accounts payable (AP). The firm serves clients across tech, healthcare, CPG, eCommerce, blockchain, and professional services, each with its own vendor mix, payment terms, and approval workflows. When Rebner arrived, every client's AP process had become what he calls a "unique snowflake."

"Everybody was doing it differently," Rebner says, "so many different vendors, so many different clients, so many different payment terms."

For many of Propeller's clients, the pre-automation state was equally messy. Startups often came to the firm with little to no financial infrastructure, and founders were tracking expenses however they could. "Receipts in a shoe box," Rebner says. "An uncomfortable conversation by the water cooler trying to figure out why things don't tie back to the statement."

With 300+ active clients and a team of 250, Propeller needed a platform that could absorb that variety and impose order on it without requiring a custom build for every new engagement.

Over 200 clients on one automated AP engine built on the BILL API Platform

Using the BILL v2 and v3 APIs, Rebner's team built an automated system that handles AP processing across more than 200 clients. The system wakes up every morning and works through a full client list. "It logs in, checks the inbox, and separates everything. This includes regular invoice, inventory invoice, credit memo, 1099, W-9, and spam," Rebner explains. "It looks at vendor history, figures out how line items have been broken out," he continues, "creates the bill, adds the approvers, and notifies the person who has to audit it."

The automation handles vendor creation, historical matching, allocation logic, and anomaly detection. Some clients generate 500 invoices a week; others produce high volumes of correspondence that the system has learned to filter out. Through it all, Propeller keeps humans in the loop for audit and approval, and now the manual entry and sorting are gone.

"The BILL API Platform makes that possible. It's industrial grade," Rebner says. "You could throw it down a flight of stairs and it's going to come running back up like Rocky. It's hardcore."

The native AI capabilities in BILL have accelerated the work even further. Rebner's team uses BILL AI agents for W-9 collection and invoice coding, and the results have exceeded expectations. "The performance exceeds the hype, which is very rare," Rebner says. "It was exactly what I anticipated it being, but then it was a little bit more."

He's equally complimentary about the platform's evolving automation features. "I love the lineage tracking. That's class," Rebner says. "And BILL introducing auto-save was a wonderful day for our automation capabilities."‍

Unlocking 1,400 client datasets to clear the path for high-impact work 

The numbers speak for themselves: 40% efficiency gains*, 15% improvement in accuracy*, and a team that can now do dramatically more with the same headcount.

"There are folks right now doing three times the level of work. Not only volume, but more intellectually satisfying work than they were previously," Rebner says.

Where the firm used to take each client's AP process as-is, it now runs what Rebner calls a "snap to grid" approach. These are standardized tiers that range from basic to comprehensive. "You're going to fit into one of these four buckets: bare minimum to platinum," he explains. That standardization, powered by BILL, is what makes it possible to serve over 300 clients without the process fragmenting again.

Over 18 years, Propeller has worked with more than 1,400 companies and clients. That history is becoming its most powerful asset.

The firm is building Propeller OS, an anonymized benchmarking platform that draws on data from across its client base, which includes the AP data flowing through BILL, to give founders something they've never had: real peer comparisons and crucial milestones on the path to growth.

"Our clients are rapidly scaling ventures. They're in a class all their own, so they don't usually have access to benchmarking data. It just doesn't exist," Rebner says. "Given the depth of Propeller's data, that's something unique we can do for them. We're rolling out anonymized benchmarking by industry and organizational size so they can finally have those comparisons."

The platform can push comparisons down to the line-item level on a P&L or balance sheet, showing clients how their spending, margins, and cash flow stack up against similar companies. It also powers marketing spend optimization and vendor competitive analytics.

Asked to describe BILL in one word, Rebner doesn't hesitate.

“BILL is reliable. It’s like my chair—it's there, it works, it holds me up. I don't need to think about it."

^{*Results as reported by Propeller Industries based on internal analysis of AP workflows across clients using the BILL API Platform April 2026. Results are based on the experience of a specific customer and are not a guarantee of future performance. Actual results will vary.}