NEW YORK — Target plans to boost its same-day delivery capability by paying $550 million for Shipt in a deal to be completed by the end of this year.

Shipt delivers groceries to its members, who pay $99 a year. Target said Wednesday that it will add more products to the service next year, such as home goods and electronics, and most of its in-store products will be available on Shipt by 2019. Target shoppers will have to make orders through Shipt’s app or website and pay the annual fee. There are plans to incorporate Shipt into Target’s app and website.

Retailers have been looking for ways to speed up delivery as they try to match the fast service offered by Amazon.com. Earlier this year, Target bought a delivery logistics company to offer same-day service to in-store shoppers.

Minneapolis-based Target expects half of its 1,800 stores to offer Shipt’s service by next summer, and that it will be available to most of its stores by the 2018 holiday season.

Shipt, founded in 2014, will operate separately from Target and remain in its headquarters in Birmingham, Ala. Shipt said it will keep working with other retailers, and Shipt said it won’t share customer data from Target’s rivals with its new owner.