ZKsync Sepolia RPC Endpoints & API | OnFinality

ZKsync Sepolia RPC Endpoints

ZKsync Sepolia is a testnet for the ZKsync Era, a zkEVM Layer 2 scaling solution for Ethereum. It provides a low-cost, high-throughput environment for developers to test smart contracts, dApps, and integrations before deploying to mainnet. The network uses zero-knowledge proofs for security and offers native account abstraction.

Why Use OnFinality for ZKsync Sepolia RPC?

OnFinality provides managed API endpoints for ZKsync Sepolia, giving developers reliable access without the overhead of running their own node. Key benefits include:

• Authenticated Access: Private endpoints with usage analytics and rate limits.
• Archive & Trace Support: Access historical state and transaction traces for debugging.
• Multiple Regions: Endpoints available in N. Virginia and Hong Kong for low latency.
• Scalable Plans: From shared API to dedicated nodes for higher throughput.

Common Use Cases

• Smart Contract Testing: Deploy and interact with contracts in a safe environment.
• QA & Staging: Validate releases before mainnet deployment.
• Wallet Integration: Test wallet connections and transactions.
• Backend Validation: Verify off-chain logic against on-chain data.

How to Connect

1. Create an OnFinality account.
2. Select ZKsync Sepolia from the network list.
3. Create an API endpoint (HTTP or WebSocket).
4. Use the endpoint URL in your dApp or script.
5. Monitor usage via the dashboard.

Network Details

• Chain ID: 300 (0x12c)
• Currency: ETH
• RPC Protocol: EVM JSON-RPC
• Transport: HTTP, WebSocket
• Explorer: sepolia.explorer.zksync.io

Public vs OnFinality RPC

Public endpoints are suitable for lightweight testing but often have rate limits and no observability. OnFinality endpoints provide authenticated access, request analytics, and a clear path to production-grade infrastructure.