Bitcoin Core development activity increased in 2025, with more contributors and higher code output supporting the network.
Casa co-founder Jameson Lopp said 135 developers contributed code last year, up from just over 100 in 2024.
The number of contributors continued a long-term recovery trend following a decline from a 2018 peak.
Developers modified roughly 285,000 lines of code during the year, marking a more than 3% increase from 2024.
Bitcoin’s strong price performance in 2025 coincided with renewed development momentum.
Lopp reported that Bitcoin Core code commits rose 1% year on year to 2,541.
Activity on the Bitcoin Development Mailing List increased by 60%, reflecting heightened technical discussion.
Developer engagement intensified amid debates over changes to the OP_RETURN data limit.
Bitcoin Core completed its first third-party security audit in November.
Security firm Quarkslab found the software to be mature and well tested, with no high or medium severity vulnerabilities.
At the time of reporting, Bitcoin price was $92,513.38.