# Cronos Integration documentation

# Integration guide for Cronos Mainnet Beta

# Setup Guide

# RPC URLs for Cronos mainnet Beta

Public RPCs URL Updates:

The Cronos RPC endpoints have been lately updated (shown as below) and it is recommended for users to update the endpoints. The old endpoints are still available for compatibility but maybe deprecated later.

Request Limits on Public RPCs:

To provide a stable experience to users, there is a request rate limit on the public RPCs to ensure fair usage. If your application requires a higher usage, please consider setting up your own nodes. You can also reach out to us on Discord (opens new window) for assistance.

Public RPCs Integration Tips:

There are more than one machines serving the public RPC services. There is no guarantee that you are served by the same machine every time. This could break the assumptions of some applications. For example when you want to broadcast multiple transactions in sequential account nonce at once, each transactions may arrive on different machines if you are not broadcasting them in a batch.

If this assumption is important in your application, please consider setting up your own nodes.

  1. Tendermint RPC

  2. Cosmos RESTful

  3. Cosmos gRPC Based

  4. EVM HTTP JSON RPC (Web3 compatible)

# Official token contract addresses for Cronos mainnet Beta

Below is the preview of the complete list of the official token contract addresses (opens new window).

Token name Address Decimal
WCRO 0x5C7F8A570d578ED84E63fdFA7b1eE72dEae1AE23 (opens new window) 18
WETH 0xe44Fd7fCb2b1581822D0c862B68222998a0c299a (opens new window) 18
WBTC 0x062E66477Faf219F25D27dCED647BF57C3107d52 (opens new window) 8
USDC 0xc21223249CA28397B4B6541dfFaEcC539BfF0c59 (opens new window) 6
USDT 0x66e428c3f67a68878562e79A0234c1F83c208770 (opens new window) 6
DAI 0xF2001B145b43032AAF5Ee2884e456CCd805F677D (opens new window) 18

# Integration guide for Cronos Testnet

# Setup Guide

# RPC URLs for For Cronos testnet


The Cronos Testnet RPC endpoints have been lately updated shown as below and it is recommanded for users to update the endpoints, while the old endpoints will still be compatible.

  1. Cosmos RPC

    • https://rpc-t3.cronos.org/
  2. gRPC Based

    • https://grpc-t3.cronos.org/
  3. Cosmos RESTful

    • https://rest-t3.cronos.org/

    • https://evm-t3.cronos.org/

# Mock token contract addresses for Cronos testnet

Token name address decimal
WCRO 0x6a3173618859C7cd40fAF6921b5E9eB6A76f1fD4 18
WETH 0x796135E94527c38433e9c42f4Cd91ca931E5e6A6 18
WBTC 0xEE200f25d7B1B9518AC944fd60b113d39bee209c 8
USDC 0x25f0965F285F03d6F6B3B21c8EC3367412Fd0ef6 6
USDT 0xa144617Afd9205AF1ceDE3Cc671da1a409A82c5a 6
DAI 0x8662A8111daEC7570a1bDF3dbd3E163d41563904 18

# API Clients and libraries

# Ethereum type JSON-RPC Methods

# Pre-requisite Readings

Below is a list of Ethereum type JSON-RPC Methods where users can curl via local node. While you can also surf to our swagger playground for a better understanding.

# JSON-RPC Methods

Method Namespace Implemented Public
web3_clientVersion Web3
web3_sha3 Web3
net_version Net
net_peerCount Net
net_listening Net
eth_protocolVersion Eth
eth_syncing Eth
eth_gasPrice Eth
eth_accounts Eth
eth_blockNumber Eth
eth_getBalance Eth
eth_getStorageAt Eth
eth_getTransactionCount Eth
eth_getBlockTransactionCountByNumber Eth
eth_getBlockTransactionCountByHash Eth
eth_getCode Eth
eth_sign Eth
eth_sendTransaction Eth
eth_sendRawTransaction Eth
eth_call Eth
eth_estimateGas Eth
eth_getBlockByNumber Eth
eth_getBlockByHash Eth
eth_getTransactionByHash Eth
eth_getTransactionByBlockHashAndIndex Eth
eth_getTransactionReceipt Eth
eth_newFilter Eth
eth_newBlockFilter Eth
eth_newPendingTransactionFilter Eth
eth_uninstallFilter Eth
eth_getFilterChanges Eth
eth_getFilterLogs Eth
eth_getLogs Eth
eth_getTransactionbyBlockNumberAndIndex Eth
eth_submitHashrate Eth
eth_getCompilers Eth
eth_compileLLL Eth
eth_compileSolidity Eth
eth_compileSerpent Eth
eth_signTransaction Eth
eth_coinbase Eth
eth_getProof Eth
eth_subscribe Websocket
eth_unsubscribe Websocket


Block Number can be entered as a Hex string, "earliest", "latest" or "pending".


While the examples below make use of local node http://localhost:8545, users may also use our public full node: https://evm-t3.cronos.org:8545/

# JSON-RPC namespaces

# Pre-requisite Readings

# Ethereum Namespaces

Namespace Description Supported Enabled by Default
eth Cronos provides several extensions to the standard eth JSON-RPC namespace.
web3 The web3 API provides utility functions for the web3 client.
net The net API provides access to network information of the node
clique The clique API provides access to the state of the clique consensus engine. You can use this API to manage signer votes and to check the health of a private network.
debug The debug API gives you access to several non-standard RPC methods, which will allow you to inspect, debug and set certain debugging flags during runtime.
les The les API allows you to manage LES server settings, including client parameters and payment settings for prioritized clients. It also provides functions to query checkpoint information in both server and client mode.
miner The miner API allows you to remote control the node’s mining operation and set various mining specific settings.
txpool The txpool API gives you access to several non-standard RPC methods to inspect the contents of the transaction pool containing all the currently pending transactions as well as the ones queued for future processing.
admin The admin API gives you access to several non-standard RPC methods, which will allow you to have a fine grained control over your nodeinstance, including but not limited to network peer and RPC endpoint management.
personal The personal API manages private keys in the key store.

# Block Explorer

# Creating API Keys on CronoScan

The CronoScan Developer APIs are designed to provide accessible and consistent Cronos data to the Cronos community. The APIs are provided as a community service with a rate up to 5 calls per second per IP. Users need to register (opens new window) for a CronoScan account to create an API key. After registration, a CronoScan user account will have a quota of up to 3 API keys.

On the CronoScan user dashboard (opens new window), select “API-KEYs” from the left-hand side column or go to https://cronoscan.com/myapikey (opens new window).


Click on the “Create a new API-KEY token” button, then optionally input an “AppName”, “My Cronos App” for example.


After the “API-KEY Token” is successfully created, a message will show up as below, and you may now use the “API key token” for your applications on Cronos!


# Community

Discord (opens new window)