The archive · Money & Fintech · Product decision · 2018–2026
Stark Bank's API-banking bet: Bezos-backed in 2022, R$600B moved by 2025
Rafael Stark bet companies would bank through APIs, not branches; after a $45M Bezos-backed round, Stark Bank moved R$600B in 2025.
Stark Bank
What the business is
An API-first digital bank for mid-size and large Brazilian companies: corporate accounts, Pix, payments, payroll, corporate debit and credit cards and accounts payable/receivable automation, plus Stark Infra, a unit selling its banking technology to third parties.
Starting capital：Bootstrapped with nearly R$1M from founder's previous startup, then $500K from angels and a $2M seed
How it started
Rafael Stark, an ITA-trained engineer who had built Android apps and founded Hummingbird after returning to Brazil in 2014, started Stark Bank in August 2018 with money from that earlier company. His trigger was a developer's gap: he was used to integrating Google Maps and Twitter APIs, yet found no bank in Brazil offered one - and he called the incumbent payments system archaic. He piloted an API for transfers and, by 2019, was handling nearly every transactional part of banking through APIs.
What happened
Stark Bank obtained a direct credit corporation (SCD) licence in October 2020 - which the company called a first for a seed-stage fintech - and raised a $13M Series A in December 2021 led by Lachy Groom, with founders of Coinbase, Dropbox, Flexport, Figma, Rappi, dLocal, Wildlife and Slack participating. Four months later, in April 2022, Ribbit Capital led a $45M Series B joined by Bezos Expeditions - the Amazon founder's first investment in Brazil - plus SEA Capital, K5 Global and founders of Airbnb and Kavak, leaving Stark Bank with $58M in cash. It served more than 300 'new economy' clients such as Loft, Buser, Daki, Cora and Bitso, had already broken even, and was moving into corporate credit.
How it ended up
The model kept compounding: Stark Bank said in February 2024 that it processed R$155B (about $27B) in payments during 2023 - a threefold jump - while net income more than doubled to R$71.5M, and by March 2025 it served roughly 800 clients, including 52 crypto-focused firms. It transacted about R$600B in 2025 and set a R$1T target for 2026, counting Ambev and iFood among clients. As of April 2026 it was still scaling: a full Brazilian bank licence filed in December 2023 remained pending, a licence abroad was sought for 2027 operations, and an IPO in the United States was planned on a five-to-ten-year horizon.
Background
Stark Bank was founded in August 2018 by Rafael Stark, an ITA-trained engineer who returned from the United States in 2014 and built Hummingbird, a digital-products company. Working with banking data as a developer, he found that no Brazilian bank offered an API - integrations were done by hand - and he started Stark Bank with nearly R$1M from Hummingbird's proceeds to build what he called the bank of the future for companies.
The wedge was a developer product: an API for transfers and refunds, with Buser among its first customers for payout automation. By 2019 Stark Bank handled almost all transactional banking through APIs, added internet banking and integrations with Excel and Google Sheets for payroll, and by 2020 held a direct credit corporation licence, which the company described as a first for a seed-stage fintech. Its vision narrowed to a bank for medium and large companies that wanted control - who approved a payment, what limits applied - rather than consumer convenience.
Capital validated the thesis: a $13M Series A in December 2021 led by Lachy Groom, with founders of Coinbase, Dropbox, Flexport, Figma, Rappi, dLocal, Wildlife and Slack, was followed in April 2022 by a $45M Series B led by Ribbit Capital with Bezos Expeditions - Jeff Bezos's first Brazil investment - alongside SEA Capital, K5 Global and founders of Airbnb and Kavak. With $58M in cash and more than 300 clients such as Loft, Buser, Daki, Cora and Bitso, the company was already breaking even.
By February 2024 Stark Bank said it processed R$155B (about $27B) in payments in 2023, a threefold rise, with net income more than doubling to R$71.5M across about 600 clients; by March 2025 it counted roughly 800 clients, including 52 crypto firms, and in 2025 it transacted about R$600B, targeting R$1T in 2026. As of April 2026, with clients such as Ambev and iFood, it was seeking full bank licences in Brazil and abroad, planning an AI banking assistant and a US IPO on a five-to-ten-year horizon.
What has to be true
- The wedge matched a real underserved job: Brazilian developers and finance teams had no API to automate payments, refunds and payroll, so early customers pulled the product roadmap themselves.
- It aimed at companies, not consumers, betting that control features - approval rules, per-category spending limits, audit trails - would beat convenience in B2B banking.
- Profitability came before the big rounds: breaking even early let Stark Bank scale on its own numbers and attract investors like Bezos Expeditions without a forced growth narrative.
- The central bank's open-finance and Pix mandates turned regulation into tailwind: API-native infrastructure became the compliant way to plug into Brazil's real-time payments system.
What can be applied
Sell the integration your customers already want: Stark turned one developer's API pain into payroll and cards, then followed client requests into a full bank while staying profitable before scaling.
Aftermath
As of April 8, 2026, Stark Bank is a profitable, privately held corporate digital bank in Brazil that transacted about R$600B in 2025 and targets R$1T in 2026. Its roughly 800 corporate clients include Ambev and iFood. Founder Rafael Stark told CNN Brasil that its full Brazilian bank licence (filed December 2023) is still pending, that it applied abroad to start operations in 2027, and that it is capitalized enough to skip further funding rounds; a US IPO is envisioned in five to ten years.
Sources
- Bezos Backs Brazil's Stark Bank In Series B Round
- Stark Bank Sees Opportunity to Serve Brazil's Crypto Startups Ignored by Traditional Banks
- Capital Insights: Stark Bank quer chegar ao exterior em 2027, diz fundador
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