This is the short presentation of how does the theorem works at a high level. This presentation introduces Metamask, Infura, Etherscan, ... and how those systems interact with smart contracts.

1. Login to Metamask
Send transaction
(buy creeptoma)
Call
infura service
(currently free)
Select one node
+
execute
transaction/query
Choose one node
execute
transaction/query
Send query
directly to infura
(without login.
i.e: get creeptoma price)
Send directly
to one node
MainNet
Blockchain
TestNet
Blockchain

3. contract Creeptoma {
function int getCreeptomaPrice(){}
}
Deploy
- directly to one node
- through infura
0x3cd9498845833058e48fde…
Creetoma.getCreeptomaPrice()
Call method
of
smart contract
Local
Blockchain
TestNet
Blockchain
(8GB)
MainNet
Blockchain
(>1TB)

5. 20,000 gas
3$/ 1gas
1$/ 1gas
3$/ 1gas : gas price
20,000: gas used
// Estimate:
// Gas price: 1 gas = 10 Gwei
// 1 Ether = 650$
// return a string
export function estimateGasToUSD(gas) {
return gweiToEther(gas * 10 * 750) + '$';
}

7. verify manual

8. On Chain vs Off Chain Solution