DSProxyFactory

function isProxy(address)(bool)

To determine whether a user has a proxy contract, you can use the following approach in your Solidity smart contract:

Abi:

[
    {
        "type":"constructor",
        "inputs":[

        ]
    },
    {
        "type":"function",
        "stateMutability":"nonpayable",
        "outputs":[
            {
                "type":"address",
                "name":"proxy",
                "internalType":"address payable"
            }
        ],
        "name":"build",
        "inputs":[

        ],
        "constant":false
    },
    {
        "type":"function",
        "stateMutability":"nonpayable",
        "outputs":[
            {
                "type":"address",
                "name":"proxy",
                "internalType":"address payable"
            }
        ],
        "name":"build",
        "inputs":[
            {
                "type":"address",
                "name":"owner",
                "internalType":"address"
            }
        ],
        "constant":false
    },
    {
        "type":"function",
        "stateMutability":"view",
        "outputs":[
            {
                "type":"address",
                "name":"",
                "internalType":"contract DSProxyCache"
            }
        ],
        "name":"cache",
        "inputs":[

        ],
        "constant":true
    },
    {
        "type":"function",
        "stateMutability":"view",
        "outputs":[
            {
                "type":"bool",
                "name":"",
                "internalType":"bool"
            }
        ],
        "name":"isProxy",
        "inputs":[
            {
                "type":"address",
                "name":"",
                "internalType":"address"
            }
        ],
        "constant":true
    },
    {
        "type":"event",
        "name":"Created",
        "inputs":[
            {
                "type":"address",
                "name":"sender",
                "indexed":true
            },
            {
                "type":"address",
                "name":"owner",
                "indexed":true
            },
            {
                "type":"address",
                "name":"proxy",
                "indexed":false
            },
            {
                "type":"address",
                "name":"cache",
                "indexed":false
            }
        ],
        "anonymous":false
    }
]