Join us at zkHack Berlin Hackathon, where we’re bringing Relayer, zkVerify’s new REST API service for ZK proof verification, along with $1,000 in bounties for the best zkApps.

🗓 Date: 20–22 June 2025

📍 Location: w3.hub, Möckernstraße 120, 10963 Berlin

This hackathon is the first stepping stone for projects aiming to secure funding from the Horizen Grants Program, opening doors for long-term support and incubation post-hackathon.

We’re especially excited to connect with builders exploring advanced ZK applications like:

• Fair gaming

• AI verification

• Private communications

• Provable randomness

  …and more.

What is zkVerify Relayer?

zkVerify is a high-performing blockchain dedicated to ZK proof verification at scale. It is a key layer in the Horizen tech stack, enabling efficient and scalable ZK proof verifications for builders and users alike.

The zkVerify Relayer is a lightweight REST API service built by Horizen Labs that streamlines the verification process even further for developers. It’s fast, flexible, and frictionless, making it ideal for devs who want to integrate ZK without becoming ZK experts.

By using zkVerify with its Relayer, builders benefit from:

• The capability to support various proof systems

• Ultra-fast Verification

• Cost-efficiency and scalability

• Developer-friendly toolings

• Future-proof design

The Reward

We’re awarding $1,000 to the best project that integrates the zkVerify Relayer service during zkHack Berlin.

Your zkApp should:

• Be built during zkHack Berlin (no pre-existing code)

• Integrate the zkVerify Relayer to verify a zero knowledge proof

• Use any of supported proof systems: zkverify.io/supported_proofs

• Interact with the zkVerifyAttestation smart contract on Base Sepolia

Bonus points if:

• You abstract the Relayer so end users don’t need to know it’s there

• You demo a clear ZK use case (e.g., identity, scores, access, compliance)

• Your app is functional, intuitive, and testable

Rules for Hackathon

This contest is to develop new and innovative applications using ZK proofs that can be verified on zkVerify with Relayer.

Requirements:

• Projects must be created by the team or individual submitting them.

• Code must be written during the hackathon. No prior submissions or reused projects allowed.

• Projects may not include code under non-permissive licences.

• Forking previous work is allowed only if significantly adapted for use with the zkVerify Relayer.

• A clear commit history during the hackathon period is required.

Relayer Integration

• Projects must integrate the Relayer for ZK proof verification.

• Any of the verifiers listed at zkverify.io/supported_proofs may be used.

• The zkApp must be deployed on Base Sepolia.

• The smart contract should interact with the zkVerifyAttestation contract deployed on-chain to verify proof correctness.

Functional Requirements

Your zkApp should demonstrate one of the following:

Preferred Option (Abstracted UX):

• Users interact only with the zkApp frontend.

• End users should not need to hold funds.

• The backend must handle:

  • Submitting ZK proofs to the Relayer.

  • Listening for and processing events emitted after successful verification.

Alternative:

• A functional zkApp where Relayer is clearly integrated, even if not fully abstracted for the end user.

Submission

• Code must be submitted via a public GitHub repo.

• Include a clear README.md with the following:

  • How to set up and run the zkApp.

  • Explanation of the ZK use case.

  • Team member names and backgrounds.

  • (Optional) Architectural diagram showing integration with zkVerify and Relayer.

Judging Criteria

• Completeness and originality of the zkApp.

• Effective use of the Relayer for proof verification.

• UX: Preference given to apps that abstract away complexity for end users.

• Technical quality: proper commit history, modularity, and clean architecture.

• Clear documentation and explanation of the ZK use case.

• Bonus points for creative or high-impact use cases for zero-knowledge proofs.