Microframework

A microframework is a term used to refer to minimalistic web application frameworks. It is contrasted with full-stack frameworks.
It lacks most of the functionality which is common to expect in a full-fledged web application framework, such as:

Accounts, authentication, authorization, roles
Database abstraction via an object-relational mapping
Input validation and input sanitation
Web template engine

Typically, a microframework facilitates receiving an HTTP request, routing the HTTP request to the appropriate function and returning an HTTP response. Microframeworks are often specifically designed for building the APIs for another service or application. For example, Lumen microframework is designed for microservices development and API development.

Pseudocode example

require "foo.php";
foo::get;

Microframeworks

Bottle for Python
Camping for Ruby
Express.js for Node.js
Falcon for Python
Fastify for Node.js
Flask for Python
Scalatra for Scala
Lumen for PHP
Slim for PHP
Silex for PHP
Sinatra for Ruby
Spark for Java
Jooby for Java
Javalin for Java
Jodd for Java
Helidon for Java
Pippo for Java
Rapidoid for Java
Armeria for Java
Akka HTTP for Java
Ratpack for Java
Ktor for Kotlin
Toolatra for Tcl