Bitcoin Core Developer Event - Barcelona, Spain

Earlier this month, many Bitcoin Core developers met up in Barcelona, Spain as part of their regular twice-yearly in person meetings.

Attendees volunteered to take notes on the unconference-style sessions and the transcripts have been added to the BTC transcripts website:

- AI session

- ASMap

- BIP324 and group policy options

- BIPs editors

- Bitcoin TUI

- CAmount

- CDash

- Coins cache

- Erlay redesign

- External interfaces

- GUI repo

- Inventory send queue

- Kernel (laundry list, overview, session)

- Libevent

- Logging

- Modern crypto library

- Mutation testing

- Package relay

- Post-cluster mempool

- Private broadcast

- QML (planning, update)

- Silent payments

- Static builds

- SwiftSync

- TCP hole punching

- Template hash

Additional informal discussions, code reviews, working groups, or other sessions occurred on:

- Quantum

- Determinism in testing

- Testnet5

- MEVPool

- Wallet priorities

- Silent payments

- Coins caching

- Peer observer

- ASMap updates

- IPC updates

- Utility binaries

- Bitcoin Kernel

- QML GUI

- Deterministic simulation testing

- AI assisted code review

- BIP39 import

- BIP54

- Fuzz testing

- Mutation testing

- Static builds

- FIBRE updates

- Parallel block input fetching

https://btctranscripts.com/bitcoin-core-dev-tech/2026-05

JD and Patricia (from localhost research), Emily (from Brink), and myself organized.

A list of previous meetings is here: https://coredev.tech

Thank you to all of the volunteer scribes for taking notes.