Castle

Est. 2021·₿ Bitcoin-only

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exchangecustodian

Last verified Oct 17, 2026

Founded

Est. 2021

src: company records

Company Type

Private

src: 21Rates

Annual Fee

$0/yr

src: Castle — homepage · as of Oct 15, 2026

News & coverage

Overview Services Reviews Media1

About Castle

Castle is a financial technology company that offers bitcoin-focused treasury and banking tools for businesses. Its platform combines operating cash, high-yield reserves, and bitcoin holdings so companies can earn yield on idle dollars while stacking bitcoin over time. Castle is not a bank; banking and advisory services are provided through partners. Features highlighted on the company site include zero monthly fees and minimums, same-day liquidity, automated revenue splits into bitcoin, and integrations with common business tools such as Stripe, Square, and PayPal.

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Key Facts

Verified data

Annual Fee

Annual card fee in USD

src: Castle — homepage · as of Oct 15, 2026

Leadership

Stephen Cole

Co-founder & CEO

Joao Almeida

Co-founder & CTO

João Almeida

Co-founder & CTO

Services

Exchange: 1% fee on buys and currently 0% on sells. Automations include revenue conversions, sweep account transfers, recurring purchases, and target orders. Custody: Institutional custody is provided by BitGo at no additional cost.

Latest Media

Castle: Automating Bitcoin for Small Businesses with Stephen Cole

Castle: Automating Bitcoin for Small Businesses with Stephen Cole

Recent Reviews

No reviews yet.

Company Details

Websitesavewithcastle.com ↗

LinkedInView profile ↗

Year formedEst. 2021

Founded inRemote

Bitcoin onlyYes

Data Provenance

✓Facts verified by 21Rates research · Oct 17, 2026

✓1 sources cited on this page

21rates.com/companies/1072/castle · structured data: Organization · Person ×3 · VideoObject ×1

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