Donna Chapman wouldn’t have found her new one-story house if she hadn’t been searching for homes day and night on her Apple iPhone.

The retired systems manager was determined to return from the Boston area to move near her children and grandchildren in Orange County, Calif.

But competition among homebuyers was fierce. Chapman, who is 60, made three offers on homes, only to get outbid.

She began her search more than a year before she moved to Southern California in October, flagging homes she liked on the Redfin and Zillow mobile applications, then sending her daughter, Sarah, and real estate agent Alexia Rusinek to check them out. Sarah Chapman used a free iPhone app called Tango to beam live video of the homes to Chapman during walk-throughs.

After she moved, Donna Chapman would open Zillow’s app to learn more about cute houses, pulling up data on prior sales, property taxes and neighboring home values. She relied on Redfin to find new listings so she could jump as soon as properties hit the market.

That’s what happened when her dream home popped up on Redfin. Chapman drove by and fell in love. The next day, she and her agent toured the Corona, Calif., home, and she decided to make an offer.

But the seller’s agent already had several offers and was about to meet with the owner. She gave Chapman one hour to submit her proposal.

Using Dropbox, Chapman signed the paperwork from home and shipped off the documents electronically to Rusinek at her office. Chapman’s offer — $5,000 over the $319,900 asking price — proved to be the winning bid.

"Without the mobile apps, I wouldn’t be able to see what was on the market," Chapman said. "I would not have been able to find this house."

Real estate apps ranked by usage

Onavo Insights, which tracks mobile application traffic, found that real estate apps accounted for 9 percent of all app usage during the second quarter of 2012. Here’s the firm’s latest ranking of real estate apps based on the percentage of real estate apps used.

» Zillow: 38 percent of users
» Realtor.com: 20 percent
» Craigslist Free: 17 percent
» Trulia: 14 percent
» Redfin: 6 percent
» Homes.com: 2 percent
» ZipRealty: 1 percent
» Hotpads.com: 0.5 percent
» NY Times Real Estate: 0.5 percent
» Century21 Real Estate: 0.4 percent
» Re/Max Pros Real Estate Search: 0.2 percent
» Coldwell Banker Real Estate Search: 0.1 percent

House hunting aid

Here are some of the top apps for house hunters:

Zillow:
» Cost: free
» Websites: Zillow.com
» Devices: Apple, Google Android, BlackBerry, Windows Phone, Amazon Kindle Fire

» Features: Search results show sale and tax histories, estimated values, rent estimates and data on nearby homes. Information also is available for homes not on the market and homes for sale by owners. App also includes mortgage rates with links to lenders and a mortgage calculator.

» Limitations: Value "Zestimates" can be sketchy, and listings aren’t always up to date. Links are provided to agents who advertise, but not to listing agents, though agent names or numbers sometimes are provided.

Realtor.com:
» Cost: free
» Website: Realtor.com
» Devices: Apple, Android

» Features: Offers comprehensive listing data, with searches that include open houses and links to listing agents, as well as rentals. Shoppers can draw a circle on a map with their fingertips to see all listings in an area.

» Limitations: Doesn’t include tax or sale histories.

Trulia:
» Cost: free
» Website: Trulia.com
» Devices: Apple, Android, Kindle Fire, Windows tablet

» Features: Searches include rentals and open houses, with links to listing agents, homes with price reductions and homes in the foreclosure process. You’ll also find links to nearby restaurants, shopping, banks and schools. The iPhone app has price history data. The Android has a cool mortgage calculator with sliders to adjust factors such as price, interest rate and down payment.

» Limitations: Sometimes incomplete or out of date. Does not include sales histories.

Redfin:
» Cost: free
» Website: Redfin.com
» Devices: Apple, Android

» Features: Searches include open houses. Results include sales and listing histories, property tax data and directions to the home. App also provides notifications of new listings and price changes.

» Limitations: Data for limited geographic areas. Links are provided to Redfin agents only, although names of listing agents are provided. The map doesn’t automatically update when you drag it to a new area.

ZipRealty:
» Cost: free
» Website: ZipRealty.com
» Devices: Apple, Android

» Features: The iPhone app includes an "augmented reality" feature that displays listings and recent sales for homes viewed through the phone’s camera. But that feature isn’t available on Android versions. The app offers "walk scores," which grade a property’s walking-friendly features, along with "transit scores" that measuring access to public transportation.

» Limitations: No price or sales histories. Listing agent information is limited to their names and license number.

Century21:
» Cost: free
» Website: Century 21.com
» Devices: Apple, Android, BlackBerry

» Features: Searches include rentals, and results include comparable sales for each listing. The app also lets you explore an area’s history, climate and demographic information. And it lets you add an open house to your calendar with the touch of a button.

» Limitations: App can be slow, with loading screens appearing between searches. Android version requires either a phone number or email address to enroll.