About

Sia is a decentralized cloud storage platform that utilizes blockchain technology. It allows users to rent storage space from each other, ensuring security and affordability. The platform emphasizes privacy, as the data is encrypted and distributed across a decentralized network.

History

Siacoin was launched in 2014 with the Sia blockchain by Boston-based Nebulous, Inc. The Sia network is now developed by the non-profit Sia Foundation. The Sia Foundation is focused on developing the Sia blockchain and ecosystem. The foundation is funded by a perpetual Siacoin subsidy, which was added to the Sia blockchain by a successful hard fork (i.e., software update) adopted by a majority of the network's users in February 2021. All code, research, educational resources, and other offerings from the foundation are available to the public free of charge and through open-source licenses.

Sia connects “hosts” that have underutilized hard-drive capacity with “renters” in search of data storage. The aim is to provide peer-hosted storage of files, without the need for a single centralized entity to control the data. Files of individual users are broken up and spread across a number of hosts. These hosts need to provide proof of file storage on a regular basis in order to receive payment and not be penalized. Payment is in the form of Siacoin and penalties involve the host losing Siacoin collateral that was posted by the host. The proofs are available on the Sia blockchain for verification by miners, who also receive payment in the form of Siacoin for their verification work. Sia generates revenue from fees on all storage contracts. This is done through the existence of so-called Siafunds. When a contract is created, 3.9% of the contract fund is removed and distributed to the holders of Siafunds. Nebulous started off holding 88%, with the remainder held by early backers of Sia. Siafunds can be transferred to other addresses but are not used as payments on the platform.

In December 2024, the Sia Foundation published a milestone update detailing major improvements across the Sia ecosystem, with the primary focus on the upcoming v2 hardfork scheduled for mid-2025.

In February 2025, the Sia Foundation announced several major core releases and new grant initiatives ahead of the v2 hardfork. renterd v2.0.0 launched full v2 support, including an API refactor and complete RHP4 integration for stable, efficient renter-host interactions.

In June 2025, the Sia v2 hardfork went live, coinciding with the network's 10-year anniversary.

In September 2025, The Foundation unveiled a new Grants Development Guide, designed to streamline technical reviews and help grantees better meet milestone expectations.