João Almeida
CTO & Co-Founder at Castle
Miami, Florida, United States
Summary
👤
Senior🎓
Top SchoolJoão Almeida is a seasoned technology founder and CTO with 11 years of experience building Bitcoin-first infrastructure and payments at the intersection of security, scalability, and product usability. As Co-Founder and CTO of OpenNode he helped pioneer Lightning Network payment processing at scale, and now leads Castle to bring automated Bitcoin treasury solutions to SMBs. He combines hands-on backend engineering—evidenced by contributions to notable Lightning projects like Zap Desktop—with strategic product leadership across integrations and risk-aware asset management. Trained with a Master’s in Informatics and Computer Engineering from the University of Porto, João bridges academic rigor with pragmatic startup execution. Based in Miami, he focuses on enabling businesses to safeguard and derive long-term value from Bitcoin through automation and transparent financial tooling. An uncommon thread in his work is turning real-world Bitcoin telemetry into production-ready systems that reduce operational friction for non-crypto-native organizations.
11 years of coding experience
8 years of employment as a software developer
Masters in Informatics and Computing Engineering, Masters in Informatics and Computing Engineering at Faculdade de Engenharia da Universidade do Porto
Portuguese, English, French, Spanish
Github Skills (5)
nodejs10
javascript10
back-end-development10
lightning-network10
grpc9
Programming languages (9)
Github contributions (5)
LN-Zap/zap-desktop
Sep 2017 - Dec 2017
Zap Wallet - Cross platform Lightning Network wallet focused on user experience and ease of use ⚡️
Role in this project:
Back-end Developer
Back-end DeveloperContributions:10 commits, 10 PRs, 24 comments in 3 months
Contributions summary:João contributed to the back-end functionality of the Zap Desktop wallet by implementing features related to the Lightning Network, specifically focusing on invoice management and channel operations. They added the `subscribeInvoices` functionality, allowing the wallet to receive updates on new and settled invoices. Furthermore, the user updated endpoint documentation, fixing lint errors and refactoring code for better efficiency and maintainability.
lightninglightning-network-walletuser-experiencewalletfocused
opennodedev/opennode-node
Dec 2018 - Mar 2022
Node.js library for the OpenNode API. https://opennode.com
Contributions:11 reviews, 40 commits, 12 PRs in 3 years 3 months
apijs-libraryopennodenode-jslightning
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