Coinhub Docs

# RPC API

Coinhub uses the ethereum.request(args) method to wrap an RPC API.

The API is based on an interface exposed by all Ethereum clients, along with a growing number of methods that may or may not be supported by other wallets.

Tip

All RPC method requests can return errors. Make sure to handle errors for every call to ethereum.request(args).

# Ethereum JSON-RPC Methods

For the Ethereum JSON-RPC API, please see the Ethereum wiki (opens new window).

Important methods from this API include:

# eth_requestAccounts

EIP-1102

This method is specified by EIP-1102 (opens new window). It is equivalent to the deprecated ethereum.enable() provider API method.

Under the hood, it calls wallet_requestPermissions for the eth_accounts permission. Since eth_accounts is currently the only permission, this method is all you need for now.

# Returns

string[] - An array of a single, hexadecimal Ethereum address string.

# Description

Requests that the user provides an Ethereum address to be identified by. Returns a Promise that resolves to an array of a single Ethereum address string. If the user denies the request, the Promise will reject with a error.

The request causes a Coinhub popup to appear. You should only request the user's accounts in response to user action, such as a button click. You should always disable the button that caused the request to be dispatched, while the request is still pending.

If you can't retrieve the user's account(s), you should encourage the user to initiate an account request.

# Example

document.getElementById('connectButton', connect);
function connect() {
  ethereum
    .request({ method: 'eth_requestAccounts' })
    .then(handleAccountsChanged)
    .catch((error) => {
      if (error.code === 4001) {
        // EIP-1193 userRejectedRequest error
        console.log('Please connect to wallet.');
      } else {
        console.error(error);
      }
    });
}

# Other RPC Methods

# wallet_addEthereumChain

EIP-3085

This method is specified by EIP-3085 (opens new window).

# Parameters

  • Array

    1. AddEthereumChainParameter - Metadata about the chain that will be added to Coinhub.

For the rpcUrls and blockExplorerUrls arrays, at least one element is required, and only the first element will be used.

interface AddEthereumChainParameter {
  chainId: string; // A 0x-prefixed hexadecimal string
  chainName: string;
  nativeCurrency: {
    name: string;
    symbol: string; // 2-6 characters long
    decimals: 18;
  };
  rpcUrls: string[];
  blockExplorerUrls?: string[];
  iconUrls?: string[]; // Currently ignored.
}

# Returns

null - The method returns null if the request was successful, and an error otherwise.

# Description

Creates a confirmation asking the user to add the specified chain to Coinhub. The user may choose to switch to the chain once it has been added.

As with any method that causes a confirmation to appear, wallet_addEthereumChain should only be called as a result of direct user action, such as the click of a button.

Coinhub stringently validates the parameters for this method, and will reject the request if any parameter is incorrectly formatted. In addition, Coinhub will reject the request under the following circumstances:

  • If the RPC endpoint doesn't respond to RPC calls.
  • If the RPC endpoint returns a different chain ID when eth_chainId is called.
  • If the chain ID corresponds to any default Coinhub chains.

Coinhub does not yet support chains with native currencies that do not have 18 decimals, but may do so in the future.

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