What is Witness?

A hybrid onchain/offchain system that allows users to create, verify and consume Witness proofs.

What is a Witness proof?

A Witness proof is an onchain-verifiable proof that a data object, in the form of its unique hash, was witnessed onchain at a specific point in time.

What is Witnessed data?

Witnessed data is the term we use to describe the combination of underlying data its associated Witness proof.

What is Witness Protocol?

A series of onchain smart contracts that empowers users to create, verify and consume Witnessed data.

What is Witness API?

A centrally hosted software platform that checkpoints new merkle roots to the Witness Protocol and provides developer abstractions.

Is Witness Protocol a Layer 1 blockchain (L1)?

Our team does not refer to Witness Protocol as a L1.

Is Witness Protocol a Layer 2 blockchain (L2)?

Our team does not refer to Witness Protocol as a L2.

Here is a list of similarities and differences between Witness Protocol and popular L2s (ie Optimism, Base, Arbitrum):

  • Similarities
    • scales access to a resource provided by an L1
    • leverages L1 consensus and smart contracts to enforce a set of rules
    • leverages L1 data availability to ensure certain data is available to users
    • initializes onchain-verifiable proofs
  • Differences
    • only scales access to L1 inclusion (data existence)
    • does not require users to pay a dynamic, onchain transaction fee
    • does not scale access to stateful contract execution (ie ERC20s, AMMs, ERC721s, bridges)
    • is deployed and accessible across multiple L1s and L2s

Is Witness Protocol a Data Availability (DA) layer?

No - it does not provide cryptoeconomic or permissionless data availability guarantees. Witness leverages the data availability of underlying blockchains.

Does Witness require an onchain transaction fee per submission?


Do I have to trust Witness to include my hash and provide my proof?


Do I have to trust Witness with the underlying data of my hash?

No - Witness does not require users to expose or unveil the data underlying their submitted hashes. This provides a privacy guarantee that also lessens the incentive for the API to censor users. In the future, we may explore providing services for users interested in submitting their underlying data for public indexing.

Do I have to trust the Witness API once I have my proof?

No - the API cannot revoke or modify the onchain-verifiability of your proof based on the protocol architecture.

Is Witness Protocol different from past attempts at onchain time stamping?

Yes - since it checkpoints only to smart contract enabled blockchains, it has a different onchain architecture and uniquely empowers novel onchain composability and counterfactual indexing.

While this seems like a small difference in choice of blockchains, the implications are actually much larger. With things like the ERC721 token standard, Ethereum illustrates unique capabilities of representing and programming on top of provenance via its richly expressive execution environment. By extending the data points of provenance natively available to this execution environment, Witness can bring new scale to these usecases.

On what blockchains is Witness Protocol currently deployed?

Ethereum, Optimism, Base and multiple testnets. Reach out to us if you are interested in having Witness Protocol deployed to other public blockchains.

Can I post onchain updates to Witness Protocol?

No - currently the protocol uses a whitelist to control who can propose new onchain checkpoints in the form of consistent root hashes. This is what allows our API to aggregate and subsidize the associated costs across all users. In the future, we may explore decentralizing the operation to provide even stronger censorship and inclusion guarantees.

Can I get the logo in a different color?

Sure, check out our brand assets here (opens in a new tab).