About 403 Finance
A Delaware software company building privacy-respecting financial software.
Who We Are
403 Finance, Inc. is a Delaware corporation with one job: build financial software that treats your data as off-limits. We're funded by the people who use our products: subscriptions and usage fees, not data sales, not advertising, not "anonymized" analytics packages.
Today that means two products: Forbidden Finance, a personal budgeting app, and Transmute, a SWIFT MT ↔ ISO 20022 message conversion API for banks and fintechs. Different audiences, same principle.
Why "403"?
In HTTP, a 403 status code means "Forbidden": access denied. It's what you see when you try to access something that isn't yours. We named the company after that response, because we think your financial data should return 403 to everyone except you. Your bank balance is forbidden territory. Your spending habits are forbidden territory. Your payment messages are forbidden territory.
Every product we build inherits that principle. The consumer app locks your budget data behind row-level security and encryption. The bank-facing API is built so your payment messages stay yours: processed, converted, and handed back, not mined. The name is the guideline for every decision we make: your data is off-limits.
The Founder
403 Finance was founded by Aaron Sullivan, a cybersecurity practitioner with a background in penetration testing, application security, and privacy engineering. He spent years breaking into systems professionally, and saw over and over how carelessly companies handle the data people trust them with.
That experience shapes how we build. Security and privacy aren't features bolted on before launch; they're the starting constraints. If a design can't protect your data, it doesn't ship.
Our Products
Forbidden Finance
A privacy-first personal budgeting app: automatic bank sync, eight budget methods, net worth tracking, and a subscription-funded business model. Your budget is nobody else's business.
Transmute
A SWIFT MT ↔ ISO 20022 message conversion API for banks and fintechs navigating the payments-messaging migration. Convert messages without surrendering them.