Ethereum: calling smart contract functions from Restful APIs

Question

I am having an Ethereum Smart Contract and deployed on Ropsten TestNet network. Is there any way to call those functions using rest API? If yes please explain. If no, Please let me know how do Pre-sale of ICO works? because I believe pre-sale works similar to this.

The concepts I know says: When presale happens. The owner/organization of ICO handles it using their website. They sell the coins at a dicounted price during pre-sale by calling the functions themselves on their website.

In the case of Exchange, the ERC20 standard have its own methods such as transfer, balanceOf. They use the ERC20 standard methods of smart contract to communicate and perform transactions.

If I am wrong please correct me.

Any help/suggestion would be appreciated. Thanks.

Answer 1

I found a module called web3.js available on https://github.com/ethereum/web3.js/

Web3.js module has several api's to invoke/call your smart contract functions and also provide utilities for value conversion such as decimal to hex or string to hex like that.

Answer 2

Cindercloud has APIs designed specifically for this.