(Pocket-lint) - It's fun to imagine what a world would be like with goods being delivered to your doorstep by drones, but we're pretty close to that being a reality now, thanks to several companies that are developing drone delivery services.

Amazon, for instance, has Prime Air, which will deliver orders from Amazon.com to you. Even Uber, according to the Wall Street Journal, is looking to launch its own UberExpress drone delivery service by 2021. Uber is aiming to deliver food to you with its effort, but it'll be far from the first company to do so. Here's a look at some of its competition - from Amazon to Dominos' Pizza.

Amazon orders

In 2016, Amazon showed off its first "Prime Air" customer delivery completed autonomously by a drone. Amazon has been vague about Prime Air, but from what we can tell, customers who qualify for drone delivery can select the option during checkout (just like they would two-day shopping), then they print off a QR code supplied by Amazon, and stick it outside their house, on the lawn.

The QR code acts like a beacon, allowing the drone to find the delivery location and safely land. To qualify for 30-minute drone deliveries in the US or UK, the order must be less than five pounds (2.26kg) and small enough to fit in the cargo box that the drone will carry. The recipient must also be within a 10-mile radius of a participating fulfillment center. You can learn more about Prime Air here.

Amazon’s drone delivery service is still in its experimental phase, with the company testing different drone designs. A blue-white-and-orange model was recently on display at the Smithsonian. It’s a hybrid, with one set of rotors for vertical lift and another set that drives the drone forward.

Chipotle burritos

Chipotle once partnered with Alphabet's Project Wing, a division of X, to test its delivery drones in 2016 at the Virginia Tech Transportation Institute, or VTTI, which is about 4 miles from the main Virginia Tech campus.

The deliveries’ recipients were students who registered as volunteers with Project Wing. After receiving an invitation to participate, they were chauffeured by Project Wing to a tent situated at the top of the hill, where they could see a Chipotle food truck below. There, they ordered burritos, which were prepared and loaded into the drones. They paid for the burrito plus a delivery fee.

About 10 minutes after ordering, the drone appeared over a grassy area, lowered a box of burritos attached by a rope and then flew away. The test aimed to see if the drone could navigate smoothly enough to deliver food -- and keep it warm.

Dominos' pizzas

A New Zealand couple became the world's first couple to have a pizza delivered by drone. Domino's Pizza partnered with Flirtey's drone delivery service to fly pizzas to the backyard of Emma and Johnny Norman's home in Whangaparaoa, about 20 miles north of Auckland . Domino's said the first official delivery followed a number test-flights, including food temperature testing, and working with government.

At the time, Dominos' said it was exploring opportunities for drone delivery trials in its six other markets (Australia, Belgium, France, The Netherlands, Japan, and Germany). It also revealed the name of its first commercial autonomous delivery vehicle: Domino's Robotic Unit (known as DRU). DRU was born out of Domino's innovation lab and was expected to work alongside the company's Flirtey fleet.

In 2016, it was capable of driving up to 20 kilometres per hour, and using Google Map data and data obtained by Domino's GPS tracking. Weighing 190kg, the DRU had hot and cold food compartment. Upon receiving a delivery from it, a customer inputs a code, which opened the top hatch.

7-Eleven Slurpees

7-Eleven partnered with Flirty and the Nevada Institute for Autonomous Systems (NIAS) on the first fully autonomous drone delivery from a store to a customer's home. The UAV used GPS to navigate to the customer's home, where it hovered over the backyard and lowered each package. It was the latest in a string of drone deliveries by Flirtey, which demonstrated the first FAA-approved delivery in a US urban area.

The drone flew approximately one mile to deliver a coffee, donuts, candy, a chicken sandwich, and a Slurpee to a customer's home. The Reno resident who received the delivery said: "My wife and I both work and have three small children ages 7, 6 and 1. The convenience of having access to instant, 24/7 drone delivery is priceless. It's amazing that a flying robot just delivered us food and drinks in a matter of minutes."

Flirtey and 7-Eleven had plans to expand the drone delivery testing nationwide. 7-Eleven is largest chain in the convenience retailing industry, with more than 10,700 stores in North America. Amazon, on the other hand, has fewer than 100 distribution centers nationwide.

Super Species fresh food

EHang partnered with Super Species, Yonghui’s fresh foods store, located in M+ Park in Guangzhou, China on fresh food deliveries. The 600-square-meter store serves fresh lobsters, salmon, beef, fruits, liquor, and other foods. As for EHang, its quadrotor delivery drones can fly at the speed of 40 km/h. And each one can carry the weight of 500g and fly within a 4.5 km radius.

With this drone delivery services, a customer needs to be located near the store, then they can make an order through Yonghui’s mobile app, and the system will decide whether their order will be delivered by drone. The product is loaded into a food box under the drone and sets out on a predetermined airway. A "community courier" will receive a notice and head toward the landing point for picking up the food.

The courier then finishes the delivery to the customer's door.

King’s Walk burgers and beers

A golf course in North Dakota partnered with the Israeli startup Flytrex to deliver food and drink from the restaurant at the King’s Walk golf course outside of Grand Forks to golfers on the course. With Flytrex’s system, golfers can order and pay for food like burgers and beer through an app. It will then be loaded into a drone, which will fly to the golfers and lower down the food on a wire at a designated delivery area.

This service is meant to cut waiting time for peckish putters, plus it's supposed to solve the hassle of making golf-course staff bring golfers food and beverages across the 80-plus acres of the course. The drones, which operate within line of sight and fly over specific routes without people below, can only handle packages up to 3kg, so deliveries are best suited for small orders or restaurant food.

LaMar's donuts

LaMar's Donuts partnered with Drone Dispatch to make doughnut drone delivery a reality in Denver, Colorado. In 2017, the company delivered boxes of donuts from LaMar's to a police station, two fire departments, and the Denver Mayor - all in honor of National Donut Day.

There was a Drone Dispatch team member who received the package, as the US Federal Aviation Administration has strict rules forcing commercial drones to remain within the range of sight for the pilots at the controls, among other safety regulations. In the case of the mayor, the tasty treats were delivered to the Denver City County Building, where Mayor Michael Hancock was waiting with volunteers from the Salvation Army.

UkrPoshta mail

UkrPoshta, the Ukrainian postal service, is another organization that teamed up with Flytrex to begin testing delivery drones - this time, in several Ukrainian cities. Each delivery is made by Flytrex's drone, called Mule, which is billed as a a carbon-fibre-bodied octocopter capable of carrying 3kg (6.6lb) packages at a distance of 23km (14.3 miles) for up to 70km/h (43.5mph).

Users must schedule deliveries to designated drop off areas within their city from their smartphones, and deliveries are expected to take less than half an hour from approval to the package being delivered. Flytrex is working with UKrPohta, which has more than 12,000 post offices throughout Ukraine and is governed by the Ministry of Infrastructure of Ukraine, on the pilot project.

Interestingly, Flytrex said its Mule drone has a release mechanism with anti-tampering features, to avoid packages being stolen.

Matterson medical supplies

Matternet, a Swiss company, has a programme where it is testing delivery drones with the North Carolina Department of Transportation. The programme is one of 10 the US FAA chose nationwide to try to determine how drones can be put to commercial use in the country.

The Matternet drone can carry vials of water from a medical building across Sunnybrook and two other buildings before landing on the roof of WakeMed’s main hospital. The hope is to gradually expand the flights until drones are carrying medical samples and supplies between WakeMed facilities in different areas in the county. Matternet has also completed medical deliveries by drone in Switzerland.

Writing by Maggie Tillman.