The Jakarta Standard Tag Library (JSTL; formerly JavaServer Pages Standard Tag Library) is a component of the Java EE Web application development platform.

It extends the JSP specification by adding a tag library of JSP tags for common tasks, such as XML data processing, conditional execution, database access, loops and internationalization.

[1] In addition to JSTL, the JCP has the following JSRs to develop standard JSP tag libraries: JSTL provides an effective way to embed logic within a JSP page without using embedded Java code directly.

[12] Examples of common tasks include if/else statements and loops.

[12] It is mandatory to use a taglib directive to specify the URI of the JSTL core library using a prefix.