How to write right json format

i have json string i want to validate it i use online json format the error show please help me ": Error: Parse error on line 1: { nodes: { Creation ----^ Expecting 'STRING', '}', got 'undefined' my json :"

 {
    nodes: {
        Creation: {
            color: 'red',
            shape: 'dot',
            x: 0.4,
            y: 0,
            fixed: true,
            alpha: 1
        },
        Send_To_Modification: {
            color: CLR.branch,
            shape: 'dot',
            x: 0.4,
            y: 0,
            fixed: true,
            alpha: 1
        },
        Send_To_Verification: {
            color: CLR.branch,
            shape: 'dot',
            x: 0.4,
            y: 0,
            fixed: true,
            alpha: 1
        },
        IBAN checking: {
            color: CLR.branch,
            shape: 'dot',
            x: 0.4,
            y: 0,
            fixed: true,
            alpha: 1
        },
        Send_To_Kassip(KWD SAA Down): {
            color: CLR.branch,
            shape: 'dot',
            x: 0.4,
            y: 0,
            fixed: true,
            alpha: 1
        }
    },
    edges: {
        Creation: {
            Send_To_Modification: {
                length: 001
            },
            Send_To_Verification: {
                length: 001
            },
            IBAN checking: {
                length: 001
            },
            Send_To_Kassip(KWD SAA Down): {
                length: 001
            }
        }
    }
 }`