However, when you approach online lenders, they do ask for your income info. This is being prudent, since they may not want to give a $5000 unsecured loan to a borrower with $1500 monthly income. Most lenders have other lending guidelines aside from checking your FICO credit score, that is your how much you make monthly affects whether you can get a loan or not.
More important than having a high income is your debt to income ratio. If you earn $5000 monthly but needs to pay $4800 of credit card debts etc, financially you are no better than someone earning $1500 but debt free. Most lenders will check that your loan payments (mortgage, car loan, student loan, credit cards etc) are not more than 40% of your income.