Bitcoin Core Development Accelerates in 2025 as Ethereum Claims Scalability Breakthrough

Bitcoin Core Activity Reaches Multi-Year Highs

Development activity on Bitcoin Core, the software powering most nodes on the Bitcoin blockchain, showed significant growth in 2025 with both increased developer participation and expanded code contributions, according to data shared by Jameson Lopp, co-founder of crypto management platform Casa ^[1].

The number of individual contributors to Bitcoin Core reached 135 in 2025, up from just over 100 in 2024, continuing an upward trend in developer engagement ^[1]. While this represents substantial growth, it remains below the peak of nearly 200 contributors recorded in 2018 ^[1].

The volume of code changes also increased, with developers modifying 285,000 lines of code in 2025 compared to 276,000 lines in the previous year, marking a more than 3% increase ^[1]. Code commits to Bitcoin Core totaled 2,541, representing a 1% increase and continuing an upward trajectory since 2023, though still below the 2021 peak of nearly 3,500 commits ^[1].

Communication and Collaboration Intensify

Communication among Bitcoin developers also intensified significantly. The Bitcoin Development Mailing List, a primary forum for discussing and coordinating network changes, experienced a 60% year-over-year surge in email volume during 2025 ^[1]. Despite this substantial increase, the message count remained well below the all-time high of approximately 5,000 messages recorded in 2015 ^[1].

The heightened development activity occurred during a landmark year for Bitcoin, which continued setting new price records and reached over $126,000 in October, driven partly by major financial institutions' increased interest under a crypto-friendly Trump administration ^[1].

Major Milestones in Bitcoin Development

The year included several significant developments for Bitcoin Core. Debate centered around the OP_RETURN data limit, which was ultimately increased in October to allow larger amounts of non-financial data to be embedded in Bitcoin transactions ^[1].

In a notable achievement for security and transparency, Bitcoin Core passed its first-ever third-party security audit in November ^[1]. Security firm Quarkslab conducted the assessment and found the blockchain software to be "mature and well-tested" with no high or medium-severity vulnerabilities identified ^[1].

Ethereum Founder Claims Scalability Problem Solved

Meanwhile, Ethereum co-founder Vitalik Buterin declared that the blockchain scalability problem has been solved, pointing to two key technologies in a post on X ^[2]. He cited PeerDAS (Peer Data Availability Sampling), which has been running on the mainnet since the Fusaka upgrade in December 2025, as enhancing data availability and therefore Ethereum's scalability ^[2].

Buterin also highlighted zkEVMs (Zero-Knowledge-compatible Ethereum Virtual Machines) as the second critical technology, though he noted these currently require additional security improvements ^[2]. According to Buterin, these technologies form the foundation for a new generation of decentralized networks capable of simultaneously ensuring security, decentralization, and scalability, effectively overcoming the blockchain trilemma in practice ^[2].

Buterin projects that zkEVMs will be fully integrated into the Ethereum ecosystem by 2030, with additional scaling mechanisms including BALs, ePBS, and higher gas limits planned for introduction in coming years ^[2]. He characterized this progress as the result of a decade-long effort that began with initial data availability concepts in 2017 ^[2].

However, critics remain skeptical of Buterin's claims, arguing that Ethereum's use of Proof of Stake does not adequately guarantee decentralization ^[2].