SEO plugins are extension modules for content management systems, browsers, and software solutions. An SEO plugin expands the scope of the source software with special tasks and functions which affect search engine optimization, web analysis, online marketing, and other aspects. Depending on the source system, this includes the optimization of websites with SEO plugins for different CMS, as well as the analysis of key performance indicators for SEO plugins for web browsers. The functionality of free and paid SEO plugins is usually very different. There are countless plugins for CMS WordPress which handle special tasks related to search engines. This is similar for web browsers, with emphasis on analysis rather than active optimization.
SEO plugins can usually be installed relatively easily and added to an application. The application can be supplemented by plug-ins and add-ons from other developers, thanks to a programming interface (API), which was previously published by the developers. If a particular program cannot perform specific tasks, a plugin will handle that by expanding the program in a defined frame for the application runtime. The now obsolete Flash Player supplements a browser with the ability to display SWF files using a projector and to process multimedia content. Which functions a plug-in adds to an application depends on the task and the developers.
The principle is similar with SEO plugins. An API allows the connection of software modules to existing applications. However, without the main application, a plugin cannot work. It depends on the software and framework. The plugin registers itself in the default library of the main application and can then be called by it. The control of the functions is partly passed to the plug-in so that it can access the functions of the framework. The framework provides the architecture in which applications can be programmed.
The plugin uses only individual components and implementations of the framework, for example, classes and functions that the framework makes available. The transfer of control to the plugin is also called the inversion of control, because a modularization and an inversion of the control flow takes place. The main application is extended, but the plugin can use functions of the main application.
There are different SEO plugins for special tasks and functions for WordPress. They are available for download in the WordPress plugin directory. Whether images, image optimization, performance, caching, minifying, XML sitemaps, crawling, broken link checking, forwarding or breadcrumbs - there are corresponding plugins for all SEO aspects. Therefore, a distinction should be made between specific and general solution approaches. Only a few plugins offer extensive functionalities which can be used to optimize web projects from different perspectives.
In addition to wpSEO, All in One SEO Pack or SEO Plugin by Squirrly; WordPress SEO Plugin by Yoast is one of the most popular plugins that enables you to do search engine optimization of WordPress websites. Yoast has more than one million active installations and numerous five-star ratings. Although WordPress is already relatively search engine-friendly by itself, more powerful extensions than the main application are needed in order to handle SEO-optimized basic settings and change special details. Which SEO plugin should be selected not only depends on the available functions and the current state of the art, but also on the requirements and knowledge of the user because individual settings can cause unwanted effects, which are noticeable only afterwards. This is especially true for the advanced settings.
The WordPress SEO Plugin by Yoast allows the configuration of SEO-relevant settings, which can be changed both locally and globally. Technical content and structural optimization is possible. According to Yoast, the plugin is particularly focused on better content and provides users with a keyword focus and content previews, for example. That way, posts can be adjusted for specific keywords and the SERPs listing can be simulated. The paid premium version includes a support and extension module such as Local SEO, News SEO, and Video SEO. The Yoast SEO plugin source code is available on GitHub.
Some Yoast features at a glance
SEO plugins are almost indispensable in search engine optimization. Whether browser or CMS, the different plugins offer extensive optimization and analysis options for different application scenarios. Selecting a suitable plugin takes some thought. In developer circles the most popular plugins are well-known, but as a relatively new user of SEO plugins, it is difficult to choose the best solution. Considerable aspects such as compatibility, being up-to-date, or simple installation should be considered for new users taking a crack at a plug-in. Tests, reviews, and expert opinions can assist in making the decision. In the end, however, users have to test an SEO plug-in for themselves and assess whether it meets their requirements and achieves reliable results in the organic SERPs.