Bitcoin Core is

free and open-source software Free and open-source software (FOSS) is software available under a license that grants users the right to use, modify, and distribute the software modified or not to everyone free of charge. FOSS is an inclusive umbrella term encompassing free ...

that serves as a

bitcoin Bitcoin (abbreviation: BTC; Currency symbol, sign: ₿) is the first Decentralized application, decentralized cryptocurrency. Based on a free-market ideology, bitcoin was invented in 2008 when an unknown entity published a white paper under ...

node In general, a node is a localized swelling (a "knot") or a point of intersection (a vertex). Node may refer to: In mathematics * Vertex (graph theory), a vertex in a mathematical graph *Vertex (geometry), a point where two or more curves, lines ...

(the set of which form the Bitcoin network) and provides a bitcoin wallet which fully verifies payments. It is considered to be bitcoin's

reference implementation In the software development process, a reference implementation (or, less frequently, sample implementation or model implementation) is a program that implements all requirements from a corresponding specification. The reference implementation ...

. Initially, the software was published by

Satoshi Nakamoto Satoshi Nakamoto ( – 26 April 2011) is the name used by the presumed pseudonymous person or persons who developed bitcoin, authored the bitcoin white paper, and created and deployed bitcoin's original reference implementation. As part of the ...

under the name "Bitcoin", and later renamed to "Bitcoin Core" to distinguish it from the network. It is also known as the ''Satoshi client''. Bitcoin Core includes a transaction verification engine and connects to the bitcoin network as a full

. The software validates the entire

blockchain The blockchain is a distributed ledger with growing lists of Record (computer science), records (''blocks'') that are securely linked together via Cryptographic hash function, cryptographic hashes. Each block contains a cryptographic hash of th ...

, which includes all bitcoin transactions ever. This

distributed ledger A distributed ledger (also called a shared ledger or distributed ledger technology or DLT) is a system whereby replicated, shared, and synchronized digital data is geographically spread (distributed) across many sites, countries, or institutions. I ...

, which has reached more than 608.9 gigabytes (not including database indexes) in size as of October 2024,“Bitcoin Blockchain Size.” n.d. Ycharts.com. https://ycharts.com/indicators/bitcoin_blockchain_size. ‌ must be downloaded or synchronized before full participation of the client may occur. Bitcoin Core includes a scripting language inspired by Forth that can define transactions and specify parameters. The original creator of the bitcoin client has described their approach to the software's authorship as it being written first to prove to themselves that the concept of purely peer-to-peer electronic cash was valid and that a paper with solutions could be written. The lead developer is Wladimir J. van der Laan, who took over the role on 8 April 2014. Gavin Andresen was the former lead maintainer for the software client. Andresen left the role of lead developer for bitcoin to work on the strategic development of its technology. Bitcoin Core in 2015 was central to a dispute with Bitcoin XT, a competing client that sought to increase the blocksize. Over a dozen different companies and industry groups fund the development of Bitcoin Core. In 2019, the

MIT Media Lab The MIT Media Lab is a research laboratory at the Massachusetts Institute of Technology, growing out of MIT's Architecture Machine Group in the MIT School of Architecture and Planning, School of Architecture. Its research does not restrict to fi ...

announced donations of $900,000 would be used to fund the Digital Currency Initiative, which would mainly go to developers of Bitcoin Core.

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Further reading