MetaCoin API

For Ethereum to allow currency services (including wallets, exchanges, payment mechanisms), it is important that each coin contract satisfy a general interface. This is called the Ethereum MetaCoin API and is described here.

The interface has several calls and uses the 32-byte string method-name calling convention to differentiate between them.

• "balance" <address> Returns the current balance of <address>.
• "send" <to-address> <value> Transfers <value> currency units from caller to <to-address>. Returns 1 on success, 0 on failure.
• "send" <to-address> <value> <from-address> Transfers <value> currency units from <from-address> to <to-address>. In general, there should be additional security requirements (e.g. <from-address> should equal the originating address), or allowing only particular caller/<from-address> combinations through the approval mechanism, denoted below. Returns 1 on success, 0 on failure.

Approve API

An additional API for approving third-parties (contracts or external entities) to issue sends in proxy for your account exists. This is similar to the direct-debit system in the UK. This is more a recommendation than a standard.

• "approve" <address> <enable> If <enable> is non-zero, allows <address> to issue send API calls on this interface on behalf of the caller (though send may possibly have additional safeguards in place). If <enable> is zero, resets the state so that <address> cannot issue proxy-sends.
• "approved" <address> Returns 1 if <address> is approved for issuing proxy sends funded by the caller, 0 otherwise.