If you want to grill a potential online lender before you make an application, here are some questions to get you started:

1. What will you do to protect my credit rating? Make sure that you don't release your credit data until you've selected a particular lender to proceed with, and choose only one.

2. What is the rate on this loan, and what is its locking provision? It's great to see a low-rate loan online, but nothing's in stone until you get a written lock on the rate, points, and fees.

3. How do you handle closing? Some online mortgage brokers, particularly in the early days of the industry, have gathered ill will by not having proper loan documents or payment ready when it's time to close on the property. Find out how the online lender makes restitution for this if problems occur.

4. Will I be charged points? Remember, points are not connected to the interest rate you receive. Points are marketing fees. They pay for overhead at the lender, such as the labor needed to process the loan and other related activities. Since an online mortgage broker doesn't — or at least shouldn't — have as much overhead, it shouldn't be charging you as many points as a traditional mortgage lender.

5. What kind of closing costs do you charge? All lenders provide an estimate of closing costs at the start of the loan process and a revised, usually higher, listing of those costs within three days of closing. Again, this is where talking to others who have used the service will help. Did they see a noticeable savings on fees and costs in this process or not?

6. How will my down payment affect the cost of the loan? Some lenders require only a very small down payment of 3 or 5 percent, and some even offer zero-down-payment loans. But these may carry significant costs to offset their inherent risk. If you put down less than 20 percent, you'll have to pay for private mortgage insurance (PMI). This is true for any loan, but it's worth checking to see what your online lender will tell you.

7. What documentation will you need? As with any lender, you'll have to supply a lot of personal financial information to get the loan. Get a copy of the forms or a list of what they'll need and see if you can compare the list against that of a conventional lender to make sure they're not asking for anything out of the ordinary.

8. How will this loan be paid, and can I prepay? Will you have the option to pay your monthly mortgage payment by mail, or do you have to do it online? Also, can you pay an additional amount on your loan each month or possibly pay off the entire balance early? If a lender doesn't let you prepay, go elsewhere.

9. What's your average time to closing? Conventional mortgage providers can take a long time to process a loan based on their staffing and the pace of business. See how long it will take an online lender to close your loan.

10. What's the appeal process? If you're turned down, or if there's a problem with the loan process, what's the procedure for registering a complaint, and how does the lender respond?

If you find an online lender's customer service representatives or loan officers can't answer such questions, then you might want to find one who can or go with a traditional lender for now.