Google Inc. launched a same-day delivery service in the San Francisco Bay Area on Thursday as the world’s largest Internet search company works with retailers such as Target Corp. to compete more with e-commerce leader Amazon.com Inc.

Google has been testing the service, called Google Shopping Express, with employees for a few months. The company opened it up to the public on Thursday morning in a limited launch focused on San Francisco residents and others living south of the city from San Mateo to San Jose.