# Sphere Secures $21M Series A Led by a16z to Expand AI Tax Compliance Engine

**Author:** Zero G Talent
**Published:** 2026-11-05
**Category:** business-finance
**Tags:** yc-hiring, tax compliance, fintech, artificial intelligence, software engineering, sales

[Read on Zero G Talent](https://zerogtalent.com/blog/sphere-secures-21m-series-a-led-by-a16z-to-expand-ai-tax-compliance-engine)

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[Sphere](https://zerogtalent.com/ai-companies/get-sphere) raised a $21 million Series A funding round led by Andreessen Horowitz, with participation from Y Combinator and Felicis Ventures. The San Francisco-based company builds an automated cross-border tax compliance platform designed to handle indirect tax, including sales tax, Value Added Tax (VAT), and Goods and Services Tax (GST). Its clients include high-growth technology companies such as ElevenLabs, Replit, Windsurf, Lovable, and Deel.

The company spent 18 months building direct digital connections into more than 100 tax authorities across the United States and international jurisdictions. The core architecture combines a Django and Python backend with a Next.js and React web application that monitors indirect tax exposure, registers businesses with tax authorities, calculates transaction taxes, and files tax returns. To parse global legal codes, Sphere uses scrapers and tax-focused Large Language Models through its proprietary Tax Review and Assessment Model, or TRAM. TRAM ingests, monitors, and codifies tax rules worldwide, generating tax determinations complete with legal citations. Human experts review and approve TRAM outputs before sending data to the live tax calculation engine to prevent model hallucinations on customer transactions.

Sphere was co-founded by Chief Executive Officer [Nicholas Rudder](https://zerogtalent.com/people/nicholas-rudder) and co-founder [Adrian Sarstedt](https://zerogtalent.com/people/adrian-sarstedt). Rudder, who studied commerce and science at the University of Sydney before earning an MBA in London, previously worked at Macquarie Capital and PwC. The team originally launched an edtech marketplace called ScholarSite, participating in Y Combinator's W22 cohort and raising a $4.3 million seed round led by Felicis Ventures. While winding down the marketplace, Rudder encountered complex multi-jurisdictional tax liabilities stemming from platform gross merchandise value. Recognizing that cross-border compliance infrastructure was lagging behind global software adoption, the team pivoted to build Sphere.

According to reporting by [TechCrunch](https://techcrunch.com/2025/11/18/a16z-leads-21m-series-a-into-tax-compliance-platform-sphere/) and [Pulse 2.0](https://pulse2.com/sphere-21-million-series-a/), Sphere emerged from stealth in late 2024 and maintained monthly revenue growth above 30 percent while processing over $1 billion in transaction volume. As covered by [The Tech Buzz](https://www.techbuzz.ai/articles/sphere-lands-21m-series-a-for-ai-tax-compliance-automation), Sphere is one of only three tax software vendors worldwide with a native integration into Stripe Billing and Stripe Checkout, and it has also integrated with the NetSuite SuiteCloud Developer Network. Profiled by [The University of Sydney](https://www.sydney.edu.au/business/news-and-events/news/2026/04/07/making-global-trade-borderless.html), the 28-person team operates out of San Francisco and actively sponsors visas and relocation for international technical talent.

Sphere plans to use its Series A capital to extend its platform beyond indirect tax into withholding tax, e-invoicing, input tax, and tariffs. To support this product scope, the company is actively hiring across software engineering, AI research, domain tax expertise, and go-to-market functions. Engineering leadership roles at the San Francisco headquarters include the [Lead AI Engineer](https://zerogtalent.com/ai-jobs/get-sphere/lead-ai-engineer-4e3c5943-bd07-4ce1-8e13-68b00221d0b7) ($250,000–$280,000) and the [AI Agent Infrastructure Lead](https://zerogtalent.com/ai-jobs/get-sphere/ai-agent-infrastructure-lead-9e1defbe-b135-4117-90b0-06548fa75fa7) ($220,000–$280,000). The company is also expanding its compliance operations, recruiting remote tax specialists including an [International Indirect Tax Compliance Specialist (VAT/GST)](https://zerogtalent.com/ai-jobs/get-sphere/international-indirect-tax-compliance-specialist-vat-gst-764fbb87-b987-4007-8af8-bb34199c6f46) and an [E-Invoicing Lead](https://zerogtalent.com/ai-jobs/get-sphere/e-invoicing-lead-bb940d09-1198-45b2-9fff-797ecad4a6aa).

## Open Roles at Sphere

| Role | Location | Work Mode | Salary |
| --- | --- | --- | --- |
| [International Indirect Tax Compliance Specialist (VAT/GST)](https://zerogtalent.com/ai-jobs/get-sphere/international-indirect-tax-compliance-specialist-vat-gst-764fbb87-b987-4007-8af8-bb34199c6f46) | United States | Remote | — |
| [Sales Development Representative](https://zerogtalent.com/ai-jobs/get-sphere/sales-development-representative-5d6138d6-2012-4319-9c71-a14921117407) | San Francisco HQ | Onsite | $75,000 – $140,000 |
| [Account Executive (SF)](https://zerogtalent.com/ai-jobs/get-sphere/account-executive-sf-5fe49c1e-e380-4650-9966-11dd7ab90dd6) | San Francisco HQ | Onsite | $220,000 – $260,000 |
| [TRAM Trainer - EMEA](https://zerogtalent.com/ai-jobs/get-sphere/tram-trainer-emea-bdcdbaaf-45f0-4912-903b-41f36df989c4) | Europe | Remote | — |
| [TRAM Trainer](https://zerogtalent.com/ai-jobs/get-sphere/tram-trainer-da63116f-e66a-4a7a-8ad4-c8545a7fc0b2) | United States | Remote | — |
| [Tax Support Specialist](https://zerogtalent.com/ai-jobs/get-sphere/tax-support-specialist-713fc1b2-f2a5-4757-9d65-f8b3a2a96147) | San Francisco HQ | Onsite | — |
| [E-Invoicing Lead](https://zerogtalent.com/ai-jobs/get-sphere/e-invoicing-lead-bb940d09-1198-45b2-9fff-797ecad4a6aa) | United States | Remote | — |
| [Indirect Tax Filings Specialist](https://zerogtalent.com/ai-jobs/get-sphere/indirect-tax-filings-specialist-4ef02061-2c0a-470b-a0af-6085358d6c61) | United States | Remote | — |
| [Technical GTME](https://zerogtalent.com/ai-jobs/get-sphere/gtm-engineer-c64eb572-bb43-4cb8-9724-df7abbdf640b) | San Francisco HQ | Onsite | — |
| [AI Agent Infrastructure Lead](https://zerogtalent.com/ai-jobs/get-sphere/ai-agent-infrastructure-lead-9e1defbe-b135-4117-90b0-06548fa75fa7) | San Francisco HQ | Onsite | $220,000 – $280,000 |
| [Forward Deployed Engineer](https://zerogtalent.com/ai-jobs/get-sphere/founding-forward-deployed-engineer-7b5f39b0-6f3f-4bc4-9469-74ae9722d85a) | San Francisco HQ | Onsite | $200,000 – $260,000 |
| [Growth Lead](https://zerogtalent.com/ai-jobs/get-sphere/founding-growth-lead-52104e06-f4b8-43c3-8591-ac9a7ab56ac1) | San Francisco HQ | Onsite | $220,000 – $260,000 |
| [Lead AI Engineer](https://zerogtalent.com/ai-jobs/get-sphere/lead-ai-engineer-4e3c5943-bd07-4ce1-8e13-68b00221d0b7) | San Francisco HQ | Onsite | $250,000 – $280,000 |
| [Senior Product Engineer](https://zerogtalent.com/ai-jobs/get-sphere/founding-product-engineer-bfa759a9-f19a-4030-959e-9e29d81d6879) | San Francisco HQ | Onsite | $220,000 – $280,000 |
| [Senior Full Stack Engineer](https://zerogtalent.com/ai-jobs/get-sphere/senior-full-stack-engineer-a19140ed-172e-4d89-a3d8-27cdc0d369fd) | San Francisco HQ | Onsite | $220,000 – $280,000 |
| [Senior Backend Engineer (Infrastructure)](https://zerogtalent.com/ai-jobs/get-sphere/senior-backend-engineer-infrastructure-c7b17c18-2dde-4b83-a8a5-ff5effe94dd2) | San Francisco HQ | Onsite | $220,000 – $280,000 |
| [Account Executive (Europe)](https://zerogtalent.com/ai-jobs/get-sphere/founding-account-executive-europe-2e159b02-536e-4ce8-932a-0280af46a95d) | Europe | Remote | $220,000 – $260,000 |

[See all open roles at Sphere](https://zerogtalent.com/ai-companies/get-sphere)

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*Source: [Zero G Talent](https://zerogtalent.com), the job board for space, defense, AI, robotics and frontier-tech companies.*