Sphere has secured 21 million dollars in new funding from Andreessen Horowitz after a year of rapid growth among global technology companies struggling to keep up with increasingly complex tax rules. The startup, founded by Nicholas Rudder, has become a preferred option for finance teams at firms such as Lovable, Replit, Windsurf, Deel, Heygen, and Eleven Labs.
Regulators in Europe now require platforms including Stripe and Adyen to report potential tax evasion. Dozens of countries are introducing real-time digital reporting. At the same time, digital businesses are expanding into foreign markets earlier than ever; Stripe’s research shows most startups now sell into more than 90 countries by their second year.
Rudder started Sphere after running into international tax issues while operating an ed-tech marketplace. The earlier company stalled, but the tax problem stayed with him. After shutting down the original venture, he began speaking with CFOs and finance leaders about the most persistent barriers to cross-border expansion. Indirect tax, sales tax in the United States, VAT in Europe, and GST in markets like Australia was the one issue that came up repeatedly. Many companies were relying on traditional vendors that outsourced large parts of their international coverage to local firms, adding delays, inconsistent quality, and high fees.
Sphere took a different approach. For more than a year, Rudder built the core system in stealth, creating direct integrations with more than one hundred tax authorities worldwide. Rudder spent the year building direct integrations “local rails” into more than one hundred tax authorities around the world. These local rails allow Sphere to handle registration, calculation, filing, and remittance inside a single platform. The company paired this infrastructure with its AI-native tax engine, known as TRAM, the Tax Review and Assessment Model. TRAM collects, codifies, and monitors global tax rules and rates. It was trained using thousands of hours of expert feedback, and still uses specialists to validate and refine its outputs.
The combination has been a major draw for companies selling internationally. Since emerging from stealth in December 2024, Sphere has been signing customers at a rapid clip and growing revenue by more than 30 percent each month. It is one of only three tax vendors globally that offers a native integration with Stripe Billing and Checkout. Sphere is also part of Oracle NetSuite’s SuiteCloud Developer Network.
Andreessen Horowitz partner Marc Andrusko said the firm views Sphere as part of a new generation of infrastructure companies built for international commerce. “Sphere isn’t just another vendor. It’s a scalable platform built for the next era of compliance,” he said. “Just as Deel redefined global payroll, Sphere is transforming revenue-based compliance.”
Rudder describes the technical challenge behind the company in simple terms. “Tax is a document problem,” he said. “The rules exist online, but they’re in different formats, hard to find, and spread across languages. Understanding how they apply to each product in a company’s catalog is work AI is well suited for, as long as there are the right guardrails.”
Customer feedback reflects many of the same issues Rudder encountered during his research. Finance leaders say legacy vendors often rely on networks of local service providers to meet international requirements, creating unpredictable workflows and additional cost. “We were using another tax vendor that outsourced some of their international functionality to a network of local service providers,” said Adam Strouss, VP of Finance at Windsurf. “Managing that patchwork created a lot of administrative load. Sphere automates the entire end-to-end compliance process on one platform, giving us peace of mind as we scale.”
Sphere’s system can be set up in under 24 hours and integrates with major billing tools. The company plans to use the new funding to expand TRAM beyond indirect tax into areas such as input tax, withholding tax, e-invoicing, and tariffs areas many global companies struggle to navigate as they move into new regions.
Rudder often points to the period when the ed-tech venture failed as the turning point. Investors disappeared, friends stopped taking calls, and he had to confront the possibility of bankruptcy with medical bills piling up. “You come out of that knowing your endurance,” he said. “Nothing will be as hard as that low point.”
The year that followed was spent building the international connections and infrastructure that became the foundation of Sphere. The company came to market in early 2025 and quickly began migrating customers from older systems and now averaging two migrations each week.
“For us, tax has always been a document problem,” Rudder said. “Our goal is simple,” Rudder said. “We want to make selling globally as easy as selling locally.”
