Abubakar Sadiq Ismail

I currently contribute full-time to Bitcoin Core. I work from the 2140 Bitcoin protocol development office in Amsterdam, Netherlands, sponsored by Btrust and 2140.

I was raised in Nigeria and earned a Bachelor of Technology in Computer Science from Modibbo Adama University in Yola, Nigeria.

I started working professionally as a software developer during my third year of university. Most of my work has been on the server side, though I’ve occasionally worked on frontend projects too.

I discovered Bitcoin open-source development in 2023 through the Btrust Builders Fellowship (formerly Qala). Bitcoin offered a chance to work with C++, cryptography, and decentralized systems while tackling one of humanity’s pressing problems: a broken financial system. This aligned with my goal of studying low-level systems, networks, mathematics, and algorithms. Hence, I left my job and started contributing to Bitcoin Core full-time in March 2023. Since then, I worked on fee rate estimation, the mempool component, and other critical parts of the software.

In 2024, I interned at Chaincode Labs, further deepening my understanding of the Bitcoin protocol.

Beyond my technical work on Bitcoin Core, I mentor new contributors through the Btrust Builders program and Summer of Bitcoin. Occasionally, you can also find me hosting the Bitcoin Core PR Review Club.