A parent/child model for smart contracts enables the smart contracts to be updateable without compromising the immutability of the underlying data. As a first step, a parent smart contract (Client Contract) is deployed that stores any other contract that may be called using the contract address. Then, whenever a new child smart contract (Service Contract) is deployed, the parent smart contract is updated with the address of the new child smart contract so that the parent smart contract will be able to call the child smart contract. The structure of the child smart contract is known to the parent smart contract. For example, the number of inputs going into the child smart contract and the number of outputs coming out of the child smart contract are known to the parent smart contract before deployment of the parent smart contract, and the transaction data remains accessible without affecting the parent contract.