Resources for Developers
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Developers are welcome to join the for technical support.
Explorer API keys for Cronos Chains are required to query block chain data, kindly follow the following instruction to obtain the API key for:
To get started with the Cronos zkEVM developer API, simply register an account on the in Cronos zkEVM developer portal, where you can access a pair of mainnet and testnet API keys on the user dashboard. You can then access the developer API service and use it to retrieve data from the available endpoints.
For detailed documentation of Cronos Chain, kindly visit:
Cronos zkEVM -
Cronos EVM -
Chain ID: 388
Token: zkCRO ("Cronos zkEVM CRO")
JSON RPC API (rate limited):
WebSocket (rate limited): wss://ws.zkevm.cronos.org
Blockchain explorer:
Gas price: ⚠️ The gas price is currently fixed at 1250 gwei
This is subject to change and is expected to be dynamic in the next major release to be announced.
Developer portal:
Contract verification interface:
Bridge for ERC-20 tokens (Ethereum <=> Cronos zkEVM):
Chain ID: 240
Token: zkTCRO
WebSocket (rate limited): wss://ws.testnet.zkevm.cronos.org
Gas price: ⚠️ The gas price of is currently fixed at 1250gwei
This is subject to change and is expected to be dynamic in the next major release to be announced.
Chain ID: 25
Chain ID: 338
JSON RPC API (rate limited):
Blockchain explorer:
Developer portal:
Contract verification interface:
zkTCRO faucet:
for smart contract developers
Testnet bridge for ERC-20 tokens (zkEVM testnet <=> Ethereum Sepolia):
JSON RPC API:
Block explorer:
JSON RPC API:
Block explorer: