In computer programming, a snippet is a relatively small amount of source code that is stored and later inserted into a larger codebase as part of the process of writing the code. Some development tools such as a code editor or an integrated development environment (IDE) provide snippet management features to enhance productivity by allowing a developer to insert a fragment of code instead of typing it.

In contrast to an abstraction construct, such as a function, a snippet is a form of copy and paste programming – a macro operation that expands the stored template text and inserts the result into the source code. Snippet insertion is similar to a preprocessor macro except that it's inserting the expansion of the macro definition rather than referencing it. Changing the snippet after insertion does not affect the code as does changing the definition of a preprocessor macro. For this reason, best practice is to use a snippet only for relatively simple code such as a function prototype, control structure, or library import. A snippet is typically used when an abstraction is not available (i.e. not supported by the programming language) or not desirable (i.e. due to runtime overhead).

A development tool that provides snippet management typically provides for maintaining a catalogue of stored templates that involves operations such as view, add, delete, edit, and rename. Notable tools that support snippet management include: Eclipse, NetBeans, Visual Studio and Dreamweaver. Snippet features like completion and placeholder substitution can be used in shells such as bash and PowerShell.

Integrated development environments often supports snippet by implementing the Language Server Protocol which support snippets.

Snippets can be classified according to the interactivity in using it, including:

A placeholder is a part of a snippet that is replaced at insertion-time. Generally, a placeholder has special markup syntax that allows the development tool to identify the boundaries of each placeholder so that it can replace it. Some tools provide a graphical user interface (GUI) in which the user can replacement values.

A placeholder is usually delimited in a snippet with special syntax and may be identified by a name or a number. The following snippet text uses identified placeholders: first_name, last_name, and item:

With an identified placeholder, a snippet can use the same replacement value multiple times. In the previous example, the placeholder first_name is an example of this use.