In October 2008, Nakamoto published a paper on the cryptography mailing list at metzdowd.com describing the bitcoin digital currency. It was titled "Bitcoin: A Peer-to-Peer Electronic Cash System". In January 2009, Nakamoto released the first bitcoin software that launched the network and the first units of the bitcoin cryptocurrency, called bitcoins. Satoshi Nakamoto released the Version 0.1 of bitcoin software on Sourceforge on 9 January 2009.

Nakamoto claimed that work on the writing of the code began in 2007. Nakamoto knew that due to its nature, the core design would have to be able to support a broad range of transaction types. The implemented solution enabled specialized codes and data fields from the start through the use of a predicative script.

Nakamoto created a website with the domain name bitcoin.org and continued to collaborate with other developers on the bitcoin software until mid-2010. Around this time, he handed over control of the source code repository and network alert key to Gavin Andresen, transferred several related domains to various prominent members of the bitcoin community, and stopped his involvement in the project. Until shortly before his absence and handover, Nakamoto made all modifications to the source code himself.