ZKsync Sepolia RPC Endpoints & API

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.

ZKsync Sepolia RPC resources

Teams usually use ZKsync Sepolia to test app behaviour, wallet flows, and backend requests before a production release, not to make a long-term infrastructure decision on day one.

Best fit: testnet testing workflows for developer testing, integrations, and rollout prep.

What builders usually check first:

• Run contract, wallet, and backend checks before sending users to mainnet.
• Keep QA and staging environments close to the production chain model.
• Validate reads, writes, and event handling with low-risk test traffic.
• Move from shared testnet access to mainnet or dedicated infrastructure when release traffic becomes predictable.

Supported capability notes:

• Authenticated ZKsync Sepolia RPC/API access for developer testing, integrations, and rollout prep.
• Flexible HTTP and WebSocket access for app, backend, and integration workflows.
• Archive-capable workflows when the product needs older chain state.
• Trace-ready workflows for teams that need to inspect execution paths.
• A lower-risk place to validate contracts, wallets, and backend behaviour.

Decision notes:

• Environment: testnet. Protocol family: EVM JSON-RPC.
• Flexible HTTP and WebSocket access is listed for supported app and backend workflows.
• Archive support is available for historical state or older chain-data queries.
• Trace support is available for transaction debugging and execution analysis.
• Available regions listed by the network spec include N.Virginia, Hong Kong.

A quick connection check usually starts with eth_blockNumber, then moves into the exact methods your wallet, dashboard, bot, indexer, or backend service needs.

Planning the next step:

• Use this network for integration confidence first: contract calls, wallet flows, event handling, and backend jobs.
• Before launch, repeat the same checks against the target mainnet and review pricing or dedicated-node needs.

Next steps:

• Create or manage RPC endpoints
• Review RPC pricing
• Read the RPC provider selection guide