A sports prototype, sometimes referred to as simply a prototype, is a type of race car that is used in the highest-level categories of sports car racing. These purpose-built racing cars, unlike street-legal and production-based racing cars, are not intended for consumer purchase or production beyond that required to compete and win races.
Prototype racing cars have competed in sports car racing since before World War II, but became the top echelon of sports cars in the 1960s as they began to replace homologated sports cars. Current ACO regulations allow most sports car series to use two forms of cars: grand tourers (GT), based on street cars, and prototypes, which are allowed a great amount of flexibility within set rule parameters.
In historic racing, they are often called "sports racing cars". Sometimes, they are incorrectly referred to as "Le Mans cars", whether they are competing in the Le Mans race or not.   
Since the 1960s, various championships have allowed prototypes to compete. However, most championships have had their own set of rules for their prototype classes. Listed here are some of the more commonly known types of prototypes.
Auto racing is a motorsport involving the racing of automobiles for competition.
Stock car racing is a form of automobile racing run on oval tracks and road courses measuring approximately 0.25 to 2.66 miles. It originally used production-model cars, hence the name “stock car”, but is now run using cars specifically built for racing. It originated in the southern United States; its largest governing body is NASCAR. Its NASCAR Cup Series is the premier top-level series of professional stock car racing. Australia, Canada, New Zealand, Mexico, Brazil and the United Kingdom also have forms of stock car racing. Top-level races typically range between 200 and 600 miles in length.
Sports car racing is a form of motorsport road racing which utilises sports cars that have two seats and enclosed wheels. They may be purpose-built prototypes or grand tourers based on road-going models. Broadly speaking, sports car racing is one of the main types of circuit auto racing, alongside open-wheel single-seater racing, touring car racing and stock car racing. Sports car races are often, though not always, endurance races that are run over particularly long distances or large amounts of time, resulting in a larger emphasis on the reliability and efficiency of the car and its drivers as opposed to outright car performance or driver skills. The FIA World Endurance Championship is an example of a sports car racing series.
Motorsport, motorsports or autosports is a global term used to encompass the group of competitive sporting events which primarily involve the use of motorized vehicles. The terminology can also be used to describe forms of competition of two-wheeled motorised vehicles under the banner of motorcycle racing, and includes off-road racing such as motocross.
The American Le Mans Series (ALMS) was a sports car racing series based in the United States and Canada. It consisted of a series of endurance and sprint races, and was created in the spirit of the 24 Hours of Le Mans.
The 24 Hours of Daytona, also known as the Rolex 24 At Daytona for sponsorship reasons, is a 24-hour sports car endurance race held annually at Daytona International Speedway in Daytona Beach, Florida. It is run on the Sports Car Course layout, a 3.56-mile (5.73 km) combined road course that uses most of the tri-oval plus an infield road course. Held on the last weekend of January or first weekend of February as part of Speedweeks, it is the first major automobile race of the year in North America. The race is sanctioned by IMSA and is the first race of the season for the IMSA SportsCar Championship.
Endurance racing is a form of motorsport racing which is meant to test the durability of equipment and endurance of participants. Teams of multiple drivers attempt to cover a large distance in a single event, with participants given a break with the ability to change during the race. Endurance races can be run either to cover a set distance in laps as quickly as possible, or to cover as much distance as possible over a preset amount of time.
The International Motor Sports Association (IMSA) is a North American sports car racing sanctioning body based in Daytona Beach, Florida under the jurisdiction of the ACCUS arm of the FIA. It was started by John Bishop, a former executive director of SCCA, and his wife Peggy in 1969 with help from Bill France Sr. of NASCAR. Beginning in 2014, IMSA is the sanctioning body of the WeatherTech SportsCar Championship, the premier series resulting from the merger of Grand-Am Road Racing and the American Le Mans Series. IMSA is owned by NASCAR, as a division of the company.
Grand-Am Road Racing or Grand-Am was an auto racing sanctioning body that was established in 1999 to organize road racing competitions in North America. Its primary focus was the Rolex Sports Car Series, an endurance racing championship series. It sanctioned five auto racing series. The series announced in September 2012 that it would be merging with the American Le Mans Series, which had been Grand-Am's main US competitor since its inception. The two series fully merged in 2014 under the banner of the TUDOR United SportsCar Championship, with the International Motor Sports Association.
The 24 Hours of Le Mans is an endurance-focused sports car race held annually near the town of Le Mans, France. It is the world's oldest active endurance racing event. Unlike fixed-distance races whose winner is determined by minimum time, the 24 Hours of Le Mans is won by the car that covers the greatest distance in 24 hours. The cars on this track can go up to 366 km/h (227 mph), and in prior events reaching 405 km/h (252 mph) before track modifications. Racing teams must balance the demands of speed with the cars' ability to run for 24 hours without mechanical failure.
A Le Mans Prototype (LMP) is the type of sports prototype race car used in the 24 Hours of Le Mans, FIA World Endurance Championship, IMSA SportsCar Championship, European Le Mans Series and Asian Le Mans Series. Le Mans Prototypes were created by the Automobile Club de l'Ouest (ACO). The technical requirements for an LMP include bodywork covering all mechanical elements of the car. Currently, there are three classes within Le Mans Prototypes, designated LMP1, LMP2, and LMP3.
The World Sportscar Championship was the world series run for sports car racing by the FIA from 1953 to 1992.
A Daytona Prototype is a type of sports prototype racing car developed specifically for the Grand American Road Racing Association's Rolex Sports Car Series as their top class of car, which replaced their main prototype racing class, specifically Le Mans Prototypes (LMPs). The cars later competed in the merged series of the WeatherTech SportsCar Championship, from 2014-2016, before being phased out and replaced by the Daytona Prototype International class in 2017. They are named after the main series event, the Rolex 24 at Daytona.
The Rolex Sports Car Series was the premier series run by the Grand American Road Racing Association. It was a North American-based sports car series founded in 2000 under the name Grand American Road Racing Championship to replace the failed United States Road Racing Championship. Rolex took over as series sponsor in 2002.
Advanced Engine Research, Ltd. is an auto racing engine manufacturer based in Basildon, Essex, England. Established in 1997, AER has developed winning engines for a number of high-profile international race series in sports car, prototype racing, rallying, touring car, and open wheel racing. They have designed engines derived from road car platforms, but their emphasis is on clean sheet designed engines with a focus on electronics and turbochargers. Their engines have raced in the 24 Hours of Le Mans, the World Endurance Championship (WEC), the European Le Mans Series (ELMS), the United SportsCar Championship (TUSC), GP3, British Touring Car Championship (BTCC), Nissan/Renault World Series, Grand-Am, Paris Dakar and FIA Sportscar Championship. They have worked with a number of manufacturers including Mazda, Ford, Hyundai, MG/Rover, Nissan, and Toyota. In 2012, AER developed and built Formula One turbo test engines to current rules and in July 2012, AER was chosen as engine partner and supplier to the new GP3 racing series. They currently supply engines for the Indy Lights series.
Porsche has been successful in many branches of motorsport of which most have been in long-distance races.
IMSA GT was a sports car racing series organized by International Motor Sports Association. Races took place primarily in the United States, and occasionally in Canada.
The IMSA SportsCar Championship, currently known as the IMSA WeatherTech SportsCar Championship under sponsorship, is a sports car racing series based in the United States and Canada and organized by the International Motor Sports Association (IMSA). It is a result of a merger between two existing North American sports car racing series, the American Le Mans Series and Rolex Sports Car Series. At its inception, the name was United SportsCar Championship, which subsequently changed to IMSA SportsCar Championship in 2016. Rolex SA's Tudor brand was the championship's title sponsor in 2014 and 2015, and since 2016 WeatherTech has served as title sponsor.
Auto racing began in the mid-19th century. It became an organized sport, which has grown in popularity ever since.
A Le Mans Hypercar (LMH) is a type of sports prototype race car that competes alongside LMDh entries in the Hypercar class of the FIA World Endurance Championship. It will also compete in the Grand Touring Prototype (GTP) class of the IMSA SportsCar Championship from 2023.