Unreal String Classes

If you are displaying a string to the end user, 99% of the time you want to be using this string type. It is mutable, provides nice formatter methods, and has built in engine localization support. In memory, FTexts store localization keys that point to external data providing the string’s contents.

Special edits have been made to the modding engine to enable mods to take advantage of Unreal’s localization system at the per-plugin level. Read more about how to use it on the Localizing Mods page.

Read more on the UE docs page for FText.

In modding, FText should be used for any string you plan to display to the user. For example, schematic names, item descriptions, UI text, predefined chat messages, etc.

FNames are designed to be more efficient in cases where you are using a string as an identifier. They are case-insensitive and immutable. The actual string contents of an FName are stored once in a global data table. In memory, they are a 4 byte identifier that can be used with this table to retrieve the related string.

FNames are useful as keys in maps because checking their equality is fast regardless of the length of the string.

Read more on the UE docs page for FName.

In modding, FNames should be used in identifier, keys, or any other string you deem its optimizations beneficial.

FStrings are generic mutable strings with no additional context. They take up as much memory as they have characters and offer the "typical" string operations like find and replace, substring, concatenation, comparison, etc.

Read more on the UE docs page for FString.

In modding, FString is generally used for log messages, strings that change contents often, or strings that doesn’t benefit from the features of FText or FName.