Sphere Raises $21 Million Series A Led by Andreessen Horowitz

Sphere, the AI-native cross-border compliance engine, led by Nicholas Rudder, has raised $21 million in Series A, led by Andreessen Horowitz, with participation from Y Combinator and Felicis Ventures. The raise reflects rising demand for scalable tax solutions as companies globalize earlier and face increasing regulatory complexity.

Regulators are tightening enforcement, EU authorities now require platforms like Stripe and Adyen to report tax evasion, and many countries are adopting real-time digital reporting. At the same time, startups are expanding internationally earlier than ever; Stripe data shows most sell into 90+ countries by year two.

Founded by Nicholas Rudder, Sphere started with indirect tax (sales tax, VAT, GST) and has quickly become essential for finance teams at global tech companies, including Lovable, Replit, Windsurf, Deel, and Eleven Labs.

Sphere stands out with two strengths: direct integrations with 100+ tax authorities for fully automated filings, and an AI-native tax engine (TRAM) that continuously codifies global tax rules with expert oversight. The new funding will expand TRAM into areas like input tax, withholding, e-invoicing, and tariffs to build a complete revenue-based compliance engine.

Sphere’s momentum has accelerated with fast-growing customer adoption, strategic partnerships, and major product updates. Since emerging from stealth in late 2024, it has onboarded global customers like Lovable, Eleven Labs, Replit, Windsurf, Heygen, and Deel, achieving over 30% average monthly revenue growth. Sphere is now one of only three tax vendors with native Stripe Billing and Checkout integrations and is part of the NetSuite SuiteCloud Developer Network. Recent product advances include expanded TRAM coverage for all indirect tax categories and embedded global tax remittance across 100+ regions.

“This funding accelerates our vision of building the first AI-native cross-border compliance engine,” said Nicholas Rudder, Founder of Sphere. “Tax is ultimately a massive document-processing challenge, rules exist online but are scattered, unstructured, and multilingual. With the right guardrails, AI is ideal for interpreting and applying them. Our scalable research and international coverage keep customers compliant, save time and cost, and help businesses expand. Sphere makes selling globally as simple as selling locally.”