Sam Williams co-founded Arweave (originally Archain) in 2017 alongside William Jones, designing the blockweave data structure — a blockchain variant where each new block links to both the previous block and a randomly selected historical “recall block,” requiring miners to retrieve and prove access to that historical data to mine — creating a self-sustaining economic model for permanent data storage using a one-time storage endowment that is gradually released to miners over generations as storage costs decline according to the historical trend of ~30% annual reduction in storage costs.
Background
Sam Williams studied computer science at the University of Kent in the United Kingdom. He has described his interest in decentralization and censorship-resistant data as dating to earlier in his studies. He co-founded Arweave (then Archain) while still in university in 2017 with co-founder William Jones.
Arweave Protocol
Williams designed Arweave around solving the fundamental economics of decentralized permanent storage:
The Storage Endowment Model:
- Users pay a one-time fee to store data permanently.
- This fee is held in an endowment, with a conservative yield released to miners over time.
- The economic model assumes storage costs decline ~30%/year historically (consistent with Kryder’s Law for storage media).
- The endowment gradually shrinks in real terms but remains large enough to pay miners as storage costs fall faster than the endowment depletes.
Blockweave (vs. traditional blockchain):
- Each block in Arweave’s blockweave links to the previous block AND a randomly selected “recall block” from history.
- Miners must demonstrate “proof of access” to that historical recall block to mine a new block.
- This incentivizes miners to store as much of the historical data as possible (more storage = better chance of having the needed recall block).
- Data is replicated across the network as a natural consequence of mining incentives.
Permaweb:
Arweave supports the permaweb — a layer of permanent web applications and content hosted on top of Arweave storage. Applications built on Arweave include:
- ArDrive — Decentralized permanent file storage interface.
- Warp — Arweave smart contract engine (SmartWeave contracts).
- Akord — Encrypted Arweave storage.
- NFT metadata storage (used by major NFT collections including some Solana projects).
AO (Actor Oriented) Compute
In 2024, Williams and the Arweave team launched AO (Actor Oriented) — a decentralized hyper-parallel compute layer built on top of Arweave for permanent data. AO messages are stored on Arweave, making all computation verifiable and reproducible. AO represents Williams’s expansion of Arweave from a storage layer to a permanent, parallelized compute environment.
Funding
Arweave raised backing from Andreessen Horowitz (a16z), Multicoin Capital, Union Square Ventures, and others — one of the few decentralized storage projects to attract a16z investment.
Key Dates
- 2017 — Co-founds Archain (later Arweave) with William Jones at University of Kent.
- 2018 — Arweave testnet and rebrand from Archain.
- 2019 — Arweave mainnet launches; AR token distributed.
- 2020 — a16z, Multicoin Capital invest in Arweave.
- 2021 — Arweave becomes primary NFT metadata storage for major Solana NFT projects.
- 2024 — AO (Actor Oriented) compute platform launches.
Common Misconceptions
- “Arweave storage is expensive for permanent data.” — The one-time endowment fee is calculated to be competitive with the expected lifetime cost of cloud storage for the same duration, given declining storage cost curves.
- “Smart contracts on Arweave are like Ethereum smart contracts.” — SmartWeave (Arweave’s smart contract system) uses a lazy evaluation model where contracts are re-computed by clients rather than globally by validators — a fundamentally different execution model with significant tradeoffs.
Last updated: 2026-04