Bio

João Almeida is the CTO and Co-Founder of Castle, a leading Bitcoin treasury platform designed for small and medium-sized businesses (SMBs). At Castle, João is driving the development of intelligent Bitcoin treasury solutions that combine automation, seamless financial integrations, and secure asset management to help businesses safeguard their digital assets and unlock long-term value. Prior to Co-Founding Castle, João was Co-Founder and CTO of OpenNode, a pioneering Bitcoin payment processing company that redefined the industry by implementing and scaling the Lightning Network. As a leader in this space, João played a key role in generating, analyzing, and applying real-world data to build a global, scalable Bitcoin payment system. His work at OpenNode positioned him as a leading authority on the technical and operational challenges of building Bitcoin-centric infrastructure. With a Master’s Degree in Informatics and Computer Engineering from (ADD University), João has consistently focused on innovation, security, and scalability in Bitcoin. His career reflects a deep commitment to advancing Bitcoin’s role in global finance, leveraging technology to create trust, efficiency, and transparency in digital payments and asset management.

Experiences

Co-founder, CTO

Present
Castle

Co-founding and leading the development of a automated bitcoin treasury platform.

Co-founder, CTO

2018 - 2023
OpenNode Inc.

Leading and developing infrastructure for a lightning network based payment processor.

Software Engineer

2017 - 2018
Cultural Vistas, New York

Lead development of a student's exchange platform.

Back-End Engineer - Freelancing

2016 - 2017
OMNI Online Solutions, California

Development of customized integrations between different software stacks to automate processes that previously were manual.

Back-End Engineer - Freelancing

2016 - 2017
Barbells for Boobs, California

Development of integrations with their main fundraising platform, Classy, to create customized extensions to be displayed on the website. Using Classy information to trigger special prizes on wooCommerce store. Responsible for money transactions data migration between campaigns.

Full Stack Developer - Freelancing

2016 - 2017
Artbattle, Toronto

Development of Artbattle's new website fully integrated on Wordpress with custom plugins, widgets and theme. Created an auction system fully integrated with slack to be used on the events and a data analysis dashboard.

Backend Engineer - Freelancing

2016
Ferreci USA, Los Angeles

Responsible for making the shipping proccess fully automated for all Ferreci's web stores. Custom integration between Overstock, Shipstation and WooCommerce.

Additional info

IEEE BIBM 2017 - KC, USA

November 2017

Presented Master Thesis at the premier research conference in bioinformatics and biomedicine

Deloitte ChallengeIT

October 2015

Winner Deloitte ChallengeIT @ Porto

Faculty of Biotechnology - UCP, Portuguese Society of Biotechnology

January 2012

Participation in the Finals of the VII Olympic Biotechnology

Ministry of Education

September 2007

"Entrepreneurship at School" - Speaker