For challenges related to programming or markup language syntax, including but not limited to checking syntax for validity, converting from one syntax to another or fixing invalid syntax. See also the [balanced-string] tag.

Quoting Wikipedia:

In computer science, the syntax of a computer language is the set of rules that defines the combinations of symbols that are considered to be a correctly structured document or fragment in that language.

You can use this tag for challenges that have to deal with syntax rules, including but not limited to checking syntax for validity, converting from one syntax to another or fixing invalid syntax.

The syntax rules of many languages involve the correct matching of parentheses, brackets and/or braces. If this is a major component of your challenge, consider also using the tag.