When comparing Lumen vs Zend Framework, the Slant community recommends Lumen for most people. In the question“What are the best PHP frameworks?” Lumen is ranked 17th while Zend Framework is ranked 18th. The most important reason people chose Lumen is:
Since it's basically just a minimal version of Laravel, it can be upgraded to a full Laravel app if the need arises. No need for code changes, just import the code to a new Laravel install.
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Pros
Pro Easily upgradable to Laravel
Since it's basically just a minimal version of Laravel, it can be upgraded to a full Laravel app if the need arises. No need for code changes, just import the code to a new Laravel install.
Pro Feature rich

Pro Highest performing PHP micro-Framework
Lumen is benchmarked at 100/rps (Requests Per Second) faster than Slim v3, which used to be considered the fastest and most performant micro-Framework to date with the ability to handle 1800/rps. (1900/rps vs 1800/rps respectively).
Pro Easy to use
Pro Well architected
Pro Enterprise ready
Zend is the most used PHP framework by big businesses. Zend is widely used and tested by a large number of banks, as well as companies, such as Allied Beverage, BBC, Shaklee, CarinBridge, BNP Paribas and more.
Pro Corporate backing
Partnered with Google, IBM, Adobe, Microsoft
Pro Extended predefined classes
Zend has a large library of predefined classes with which developers can create maintainable and stable web applications. This is done if the developer works within the constraints and with the components of these different predefined classes, which makes the application more maintainable.
Pro Wide database support
Zend supports almost all kinds of databases out there. From MySQL, IBM DB2, Oracle, Microsoft SQL Server to PostgreSQL.
Pro Allows customization
For developpers not used to Zend, they can use a predefined structure and use preloaded components and classes to build and maintain their application. But for advanced developpers, they can customize the structure to stick to their needs (or their likings) and extend primary Zend components for fine-tuned apps or replace the initial predefined Zend components by third parties components such as Doctrine ORM or another logging or templating framework.
Pro Easy to build an API with Apigility
Apigility is a collection of Zend Framework modules. It's useful for building the API architecture of a web app quickly and painlessly by providing a flexible engine.
Apigility also has a web-based UI that allows developers to quickly create and modify API services, configure authentication, set authorization rules, set up validation and write new documents.
Cons
Con Built for smaller tasks like APIs
Con It's based off Laravel and inherits its shortcomings
Lumen inherits many shortcomings of Laravel, such as static proxy classes.
Con Made to work alongside Laravel
Lumen as a framework is at it's full potential when used alongside it's older brother. Lumen was created to be used for microservices alongside Laravel, which is used for more user-facing applications. If a project is already using another framework other than Laravel, it would be better to use another microframework for microservices instead of Lumen.
Con Loose documentation
Since Zend has a loosely-coupled architecture, it means that the documentation will be quite loose as well. Even though there's a lot of documentation for the framework, it's still hard to use it as a guideline to create a completed project. Although this can be less of a problem considering all the tutorials and guides out there.
