Bitcoin v0.3 was released on SourceForge on July 6, 2010, five days before the Slashdot posting that would draw Bitcoin its first wave of mainstream attention.
What’s new in v0.3:
- Command line and JSON-RPC control
- Includes a daemon version without GUI
- Transaction filter tabs
- 20% faster hashing
- Hashmeter performance display
- Mac OS X version (thanks to Laszlo)
- German, Dutch and Italian translations (thanks to DataWraith, Xunie and Joozero)
The JSON-RPC interface and daemon mode were particularly significant technical additions, enabling Bitcoin to be run as a background service and controlled programmatically. This laid the groundwork for exchanges, payment processors, and other services to integrate Bitcoin. The wallet design entry traces the capability back further: JSON-RPC first appeared on SVN as v0.2.6 in February 2010, five months before this release made it a headline feature.
The Mac OS X port was contributed by Laszlo Hanyecz, who had become famous just weeks earlier on May 22, 2010 for making the first known real-world Bitcoin purchase — buying two pizzas for 10,000 BTC. Hanyecz later recalled his correspondence with Satoshi from this period.
The Slashdot article published five days after this release with the headline “Bitcoin Releases Version 0.3” brought an enormous surge of interest. The Bitcoin price rose from approximately $0.008 to $0.08 in just five days as thousands of new users discovered the project. Satoshi later described this event as a significant test of the network’s ability to handle sudden growth.