Sia / Skynet

Decentralized Storage Network

Sia is a decentralized cloud storage network where renters form cryptographic storage contracts with hosts on a Proof-of-Work blockchain, paying in Siacoin (SC). Skynet (now defunct as a hosted service, Sia continues) was a layer-2 content delivery and decentralized web protocol built on top of Sia, enabling file sharing via persistent Skylinks.

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Details

License Permissive (MIT)
Dev Status 💀 Defunct
Dev Status Detail Released (Sia actively maintained by Sia Foundation); Skynet Labs: Defunct
Owner Sia Foundation (nonprofit, Luke Champine) — core Sia protocol; Skynet Labs (David Vorick) — defunct since Nov 2022
Country USA
Start Year 2013
Stack Golang
Funding VC + personal investment (no ICO; ~$750K seed 2014; <$10M total raised by Nebulous; Sia Foundation funded via blockchain subsidy)
Last Investigated Mar 9, 2026

Use Case Domains

Platform Evolution & Sovereignty

Affordances

Self-hostable Local-first storage Data portability

Decentralized Storage Network Attributes

Origins Decentralized cloud storage / backup
Database Proof-of-Work blockchain (Siacoin); erasure-coded file shards on hosts
Query Language REST API (renterd/hostd APIs); Skynet SDK (JS, Go)
Data Formats Any binary; Skylinks (46-char encoded metadata for Skynet content)
Mobile Support N/A (infrastructure; wallet apps exist)
Web Support Yes (web portals for Skynet; renterd has web dashboard)
Native Apps Native apps (Sia Desktop app; renterd/hostd with web dashboard)
Terms Self-hosting (run host or renter node); pay-per-contract (Siacoin)
Funds <$10M raised by Nebulous Inc. through 2020; Sia Foundation funded by block reward subsidy (~30,000 SC/block) introduced via hard fork Feb 2021
Based On Novel (original PoW blockchain with smart storage contracts)
P2P Architecture Public blockchain (PoW; host-renter contracts via blockchain; Skynet adds portal layer)
Overlay Network Global
Content Addressing Yes (file shards addressed by Merkle hash; Skylinks encode content-addressed metadata)
Local-First N/A (cloud storage model)
E2EE Yes (client-side encryption of uploaded files before storage on hosts)
Byzantine Fault Tolerance Partial (PoW blockchain is BFT; individual host honesty enforced by cryptographic storage contracts and collateral slashing)
Signature Ed25519
Permissions Cryptographic Capabilities (storage contracts with host collateral; Skynet registry uses public key access control)
Semantic Web Compatibility N/A
Smart Contract Yes (storage contracts are on-chain smart contracts in Siacoin blockchain)
Protocol Stack Position Application-layer (built on TCP/IP)
Asset / Value Embedding Native (Siacoin SC embedded at blockchain level; storage contracts settle in SC)
Protocol Maturity / Standardization De Facto Standard (established since 2015; community standard for decentralized storage; no formal standards body)
Update Policy Mutable (versioned) for Sia files (hosts can update via new contracts); Skynet Registry supports mutable entries; immutable content-addressed files via Skylinks
Storage Proof Mechanism Merkle audit proof (hosts must submit cryptographic storage proofs on-chain at contract end; failure results in collateral burn and missed payment)
Economic / Incentive Model Token rewards (native token SC): renters lock SC in contracts; hosts earn SC for proven storage; both parties lose collateral for breach
Retrieval Guarantee Best-effort (incentivized via cryptographic contracts and collateral; retrieval availability depends on host uptime and contract renewal)