Fry sauce

Fry sauce is a condiment often served with french fries, fried yucca, or tostones (twice-fried plantain slices) in many places around the world. It is usually a combination of one part tomato ketchup and two parts mayonnaise.
In the United States.
Although sauce composed of a mixture of equal parts ketchup and mayonnaise appears in a New Orleans cookbook published in 1900, fry sauce was originally popularized in the United States by a chef named Don Carlos Edwards, who served it in his first restaurant, Don Carlos’ Barbecue in Salt Lake City, which eventually became the Utah-based restaurant chain Arctic Circle in the 1950s. The chain still serves fry sauce in its western United States restaurants.
In Puerto Rico, "" is widely used with , sandwiches, burgers, and fried foods. It is made of two parts ketchup and one part mayonnaise with the addition of garlic.
In April 2018, Heinz announced the release of "Mayochup", a mixture of the two sauces, because 500,000+ users voted "yes" in a Twitter poll asking Americans if they wanted to see it in stores. A number of Twitter users responded that such a mixture already existed as "fry sauce" and "fancy sauce". The sauce arrived at U.S. retailers' shelves in September 2018.
Several fast food chains have individually branded variants of fry sauce using a mayonnaise and ketchup base, including Zaxby's, Raising Cane's, and Freddy's.
The sauce is also closely related to Yum Yum sauce, which is popular in Japanese Steakhouses in America. 
Outside the United States.
In Argentina, Uruguay, Paraguay, Peru and Chile, a similar condiment known as "" (golf sauce) is a popular dressing for fries, burgers, steak sandwiches, and seafood salads. According to tradition, the sauce was invented by Luis Federico Leloir, a Nobel laureate and restaurant patron, at a golf club in , Argentina during the mid-1920s. In Spain and Colombia, it is known as salsa rosa or salsa rosada, a variant of cocktail sauce or Marie Rose sauce.
In France, many Turkish restaurants and fast food establishments serve fry sauce and call it '; it is also common for customers to request ' (a dab of mayonnaise and a dab of ketchup) alongside their French fries at such places. Both "sauce cocktail" and the thousand island-like "sauce cocktail" can often be found in supermarkets.
In Germany, a popular product called ' (red white) is sold in toothpaste-style tubes; it consists of unmixed ketchup and mayonnaise, which form a red-and-white striped string when squeezed out. Fries at restaurants are sometimes served with an equal mixture of ketchup and mayonnaise. This style of serving is often called "Pommes Rot-Weiß" or, colloquially "Pommes Schranke" (barrier gate) due to the red white coloration of those. ' or ' (fry sauce) is a lightly spiced mayonnaise similar to the Dutch '. A condiment similar to the American fry sauce is known as ", but it is more often used for döner kebab than for French fries.
In Iceland, a condiment similar to fry sauce called " (cocktail sauce) is popular.
In the Philippines, a similar sauce is made by combining mayonnaise and banana ketchup. It is commonly used as a dipping sauce for fried food like french fries and cheese sticks (deep fried cheese wrapped in lumpia wrapper) but also for appetizers like "lumpia".