Meet Calvin, a Bitcoin protocol developer sponsored by OpenSats, who is working on the Utreexo project.
Utreexo is a hash-based accumulator for the Bitcoin UTXO set. In non-technical terms, it's a way to store and retrieve necessary data about chain state to validate Bitcoin blocks and transactions.
Calvin has been working on Utreexo since 2019.
In this interview, Calvin shares how he came to work on Utreexo full-time and the exciting development milestones he anticipates reaching this year.
This interview was recorded on January 7, 2026.
Timestamps:
(2:45) Utreexo explained in Ethereum terms
(10:26) Utreexo in the Bitcoin governance process
(14:02) How Calvin joined the Utreexo team
(20:29) How the Utreexo project is funded
(25:25) The sustainability of funding for Bitcoin development work
(28:05) What Calvin might do next after Utreexo
(38:01) Utreexo development goals in 2026
(44:22) Rapid-fire questions
Links:
- Utreexo BIPs (https://github.com/utreexo/biptreexo)
- BTC Before Light newsletter on Utreexo (https://christinedkim.substack.com/p/issue-03)
- Floresta (https://github.com/getfloresta/Floresta)
- Summer of Bitcoin (https://www.summerofbitcoin.org/)
- Vinteum (https://x.com/Vinteum_org)
- OpenSats (https://opensats.org/)
