Aaron Bai and Sahil Phadnis are reshaping how traditional small businesses manage their spending. At just 20 and 22, the Affiniti co-founders are building a new kind of expense management software for small businesses — one that feels more like what fast-growing tech startups have enjoyed for years, but tailored for the needs of everyday businesses like pharmacies, HVAC shops, and car dealerships.
Their timing and execution have paid off. After raising $11 million in seed funding only six months ago, they’ve now closed a $17 million Series A, led by SignalFire. Other backers include Contrarian Thinking Capital, founded by Codie Sanchez, and notable angels like Yahya Mokhtarzada of Truebill and Austin Rief of Morning Brew. Previous investors — Indicator Ventures, Lightshed Ventures, and RiverPark Ventures — also joined the round.
Affiniti’s rapid growth and strong transaction volume — $20 million monthly from 1,800+ businesses — helped fuel investor interest. The founders believe they’re on track to hit $1 billion in transactions by year’s end.
What Makes Affiniti Different From Brex or Amex?
Small businesses already have countless credit card options. So why choose Affiniti? According to Bai, Affiniti represents the third wave of fintech. He breaks it down like this:
- v1: Traditional banks and legacy credit cards
- v2: Modern fintech like Brex and Ramp, focused on cleaner design and access to spend data
- v3: Smart, advisory-driven finance tools that help companies make better decisions
“Most of our customers don’t have in-house finance teams,” Bai explains. That’s why Affiniti’s product doesn’t just manage expenses — it analyzes them. Think: actionable insights, predictive analytics, and tailored financial advice, all packed into a user-friendly dashboard.
Today, the product includes built-in perks like custom cash-back rewards, native QuickBooks (QBO) files instead of basic CSV exports, and short-term loans of up to 90 days against invoices. And with this new funding, they plan to roll out even more features, including business banking, bill pay, advanced cash flow analytics, and deeper software integrations with tools like ERP systems and point-of-sale platforms.
What sets Affiniti apart is its focus. Rather than chasing every SMB in the country, they’re targeting select industries with complex cash flows. For instance, they’ve partnered with trade associations for independent pharmacies — giving them instant access to group purchasing deals and a trusted pathway into the market.
No YC, No Problem: Building Through Grit and Industry Smarts
Unlike many successful startups, Affiniti didn’t pass through the halls of Y Combinator or Techstars. Instead, Bai and Phadnis met at UC Berkeley and built a strong network from scratch in Silicon Valley. That hands-on hustle is reflected in how they’ve approached marketing — using strategic partnerships with niche trade groups rather than chasing broad visibility.
That focus is working. With their Series A in hand, a $15 million debt facility (scalable to $50M), and their foot firmly on the gas, Affiniti is proving that expense management software for small businesses doesn’t have to be generic or clunky. It can be smart, sector-specific, and surprisingly simple — even for a mom-and-pop pharmacy.
And judging by their 10x revenue growth in just one year, Affiniti’s not just solving a problem — they’re tapping into a massive, underserved market with urgency and precision.
