Secure
An immutable foundation for your zk-dApp. Proofs are submitted onchain via zkVerify, providing a tamper-proof audit trail for every verification.
Free Testnet Environment
Kurier Testnet is a free sandbox for developers building zero-knowledge applications. Submit and verify ZK proofs against live infrastructure — on zkVerify testnet or Base Sepolia — before deploying to mainnet. No cost. No production risk.
Full feature parity with mainnet. New proof types and networks land here first.
Read our guide.
An immutable foundation for your zk-dApp. Proofs are submitted onchain via zkVerify, providing a tamper-proof audit trail for every verification.
Optimistic verification delivers near-instant results, with onchain finality available for applications requiring full cryptographic guarantees.
A single REST API endpoint replaces the need to run a zkVerify node, manage crypto payments, or write custom proof-submission logic.
Designed to support multiple zk-proof types on various blockchain networks. See the full list of supported networks.
Kurier is a REST API built by zkVerify Foundation that abstracts the complexity of ZK proof submission and onchain verification. Instead of running your own zkVerify node or managing blockchain infrastructure, you send a proof to the Kurier API and get back verifiable, onchain results.
Kurier supports all major ZK proof systems in use today — making it the most comprehensive zero-knowledge proof verification API available.
Testnet is the recommended starting point for all new Kurier integrations:
Once your integration is stable, migrate to mainnet in minutes.
Kurier Testnet supports all of the following ZK proof systems:
Networks
Sign up for a free testnet API key at testnet.kurier.xyz
Submit a proof via POST to the Kurier testnet API endpoint
Receive a jobID and poll for real-time verification status
Proof is finalized onchain on zkVerify testnet or Base Sepolia
Validate your integration, then go to mainnet
New to ZK proofs? A zero-knowledge proof (ZKP) lets you prove that a computation was done correctly — without revealing any of the data involved. This makes ZK proofs fundamental to:
Kurier makes it easy to integrate ZK proof verification into any of these use cases via a single API.
| Q4'25 | Q1'26 | Q2'26 |
|---|---|---|
|
|
|
How to use the Kurier WebSocket API to get instant job status updates for ZK proof submissions, replacing polling with persistent real-time connections.
Learn how to integrate the Kurier Random Hash Oracle into your smart contracts for secure, unpredictable randomness through a simple subscription-based workflow.
How developers can request secure random hashes using the Kurier RNG service for games, marketplaces, and distributed applications.