What Are Plugins?

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Anna Fitzgerald
Anna Fitzgerald


Applications are everywhere. But no app can be all things to all people, and that could be why you're asking "what are plugins?"

Site owner learning what are plugins

No single piece of software can deliver every function for every user — no matter how powerful it might be. Plugins bridge the gap between form and function. They make it easier to specific features to applications and software without affecting the source code.

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But what exactly are plugins? How do they work, why do they matter — and how can you find the right plugins when you need them? To learn more, keep reading or click the topic you’re looking for below.

These pieces of software effectively "plug in" to existing operational frameworks, allowing users to get the features they want. Plugins empower developers to use technology tools that already exist instead of reinventing the digital wheel.

Consider the most popular PC operating system in the world — Windows. Used by individuals and corporations alike, Windows has offered a host of functionality. With Windows you can:

  • Create complex documents
  • Browse the World Wide Web
  • Edit photographs
  • Use familiar software programs

But Windows can’t do everything. For example, most Windows versions offer basic audio editing tools. But those tools lack the in-depth functionality of more robust solutions. Microsoft software engineers could take the time to code these audio tools and install them in new Windows releases.

But user demands and application functions are constantly evolving. This means that those audio tools will also need ongoing support to make sure those tools live up to expectations.

Plugins offer key functions without needing in-software solutions.

Your television plugs into the electrical system of your home to deliver on-demand media access. In the same way, software plugins use the existing structure of application code to provide specific functions.

For Windows, this means a host of free and paid audio plugins.

This is the biggest benefit of plugins. They make it easy for users to quickly add or remove them from software without altering primary application operations.

How do plugins work?

The idea behind plugins is simple: Developers create small pieces of software and add them to computer programs, mobile applications, or websites to improve functionality. A plugin can accomplish this without significantly increasing resource use or compelling primary software developers to offer ongoing plugin support.

Instead, plugins make use of publicly-available code structures that allow them to interface with existing software tools. In effect, this code allows them to speak the same language. Plugins can request specific resources or actions from software systems at large, allowing them to deliver targeted functionality for users.

Plugins must also strike a balance between security and accessibility. This is especially true when using plugins for business applications on corporate networks or when improving consumer website accessibility.

Software makers and operating system (OS) developers will typically define specific use parameters that govern what plugins can and can’t do in their software environments. In practice, this means that while an audio plugin will likely be able to request microphone and speaker access (that must be approved by the end-user) the same plugin won’t be granted access to more in-depth functions that aren’t related to audio output.

It’s worth noting that different software and OS developers have different approaches to plugin security. For example, Apple’s iOS ecosystem has historically favored more restrictive policies than Windows or Android, resulting in generally better security but reduced plugin functionality for users.

Why do plugins matter?

Plugins matter because they help take the burden off generic software solutions. Instead, they allow users to add the functions they want when they want them. Even better? These plugins don’t alter the underlying code, making them easy to add or remove without any negative impact on overall software function.

Just like typical software, however, plugins do require regular updates to make sure they work with the latest OS version. As a result, plugin developers must continue to support their work as connected software receives security or operational updates. If they abandon the project, plugins will eventually stop working as newer software versions outpace their design framework.

Plugins are also critical to help streamline website form and function. With a host of plugins to help site owners do everything from creating and distributing marketing emails to personalizing user content and analyzing traffic data, plugins offer key functionality without the need to worry about specific software restrictions or operational conflicts that could take websites offline.

Plugin Best Practices

Considering a plugin for your website, desktop, or mobile application? Take a look through these best practices before powering up:

1. Make security your first priority.

To deliver key functions, plugins must ask website administrators or device owners for specific permissions. These often include the ability to access certain device functions or data to help deliver desired outcomes.

The caveat? Not all plugins are secure. Some may be designed maliciously on purpose to steal or destroy data, while others suffer from poor design choices that create new security risks. In either case, always assess what permissions plugins are asking for; if a new audio plugin wants access to your email contacts and documents folder, ask why — and say no if something seems suspicious.

2. Consider plugin cost.

While many great plugins are free, that doesn’t mean they come without cost — especially if you’re using them on your website. Here’s why: The more plugins you add, the longer it takes your page to load and the more bandwidth required to deliver page features. As a result, it’s critical to find a balance between plugin potential and overall performance.

3. Limit overlapping function.

Many plugins offer multiple features or are regularly updated to include new functions. Best bet? Don’t use multiple plugins for the same purpose, since this both slows down your device or website and can lead to data fragmentation. Instead, use single plugins for a specific purpose — and remove them if that purpose is no longer served.

4. Evaluate new options.

As software evolves, plugins must keep pace to deliver value-added functionality. As noted above, if plugin developers stop updating their code, plugin features will eventually stop working.

To make sure you’re getting the best combination of software form and code framework, take time to track down "best of" plugin lists and reviews consistently. This will help you get the ideal combination of size, speed, and specific function.

Plugins have been around since the 1970s and ‘80s, with text editor and QuarkXPress add-ons. More recent plugin examples include Adobe Flash Player — which sunset in 2021, QuickTime, and Visual Assist.

For a handful of today's most popular plugin examples, keep reading.

WordPress Plugins

When you hear plugins, your next thought is probably WordPress. Plugins have been a feature of the platform since 2004. As of this writing, its directory includes over 60,000 plugins.

So, whether you want to add ecommerce, podcasting, or video to a WordPress site, you have a range of options to choose from.

Plugins are useful to WordPress for two main reasons. First, plugins don't impact core WordPress files. Plugins make it easy for users to add functionality without losing customizations.

Next, plugins make it easy for less tech-savvy users to add functionality. Instead of editing files or adding code, all users need to do is add and activate a plugin.

These are some top choices for plugins on the platform.

1. HubSpot WordPress Plugin

Best for: CRM, live chat, forms, analytics, and email marketing

Examples of plugins: HubSpot WordPress

What we like:

When it comes to plugins, less is more. So, the more utility you can get with a single plugin, the better. HubSpot's free WordPress plugin offers a useful array of tools including:

  • Live chat, forms, and popups
  • Email marketing and chatbots
  • Contact email and information sync with the HubSpot CRM
  • Campaign analytics

This plugin pulls together a range of tools for streamlined active use and tracking.

2. WP Rocket

Best for: Caching your WordPress site

Examples of plugins: WP Rocket

What we like:

While this plugin is best known for caching, it also offers other functions that can improve your site. Whether you want to speed up page load time, improve page speed, or optimize your site for mobile, this plugin is for you.

While site optimization can sound scary to beginners, this plugin is quick and simple to install and use.

3. Yoast SEO

Best for: Search engine optimization

Examples of plugins: Yoast SEO

What we like:

Search engine optimization can take time to conquer. This popular plugin offers SEO tools and automated tips to help your website rank on search engines.

Much of this SEO plugin works like training wheels on a bicycle — you're in charge, but you have something to lean on while you're figuring out the details.

This plugin also has premium options for more advanced users. Check out this list if you’re looking for more SEO plugin options.

4. Jetpack

Best for: Security and site performance

Examples of plugins: Jetpack

What we like:

Jetpack is one of the top-rated security plugins. It's known for ease of use and includes features like real-time backups, malware scanning, and one-click restores. And this plugin isn't just for security, it includes a long list of added features like:

  • Lazy image loading
  • Social sharing
  • Sitemaps
  • Image carousels

These add-ons can be incredibly helpful for any small business website.

More security plugins:

5. Smush

Best for: Image optimization

Examples of plugins: Smush

What we like:

Slow-loading website pages are a turn-off for users and one of the top culprits for slow site speed is bulky images. This plugin can help you save time with functions that can compress images in bulk. You can also use this tool to find specific images that are slowing down your site and to optimize images to create a great user experience.

Other Useful Plugins

WordPress isn't the only software that gets a boost from plugins. Websites, CRMs, and more get improved functionality with a range of plugins.

6. All In One SEO

Best for: Search engine optimization

Examples of plugins: All In One SEO

What we like:

This WordPress SEO plugin is easy to use for beginners. All In One SEO also has advanced SEO features that can help with:

  • Video SEO
  • Local SEO
  • Rich snippets
  • SEO audits

This makes it an optimal tool for solopreneurs and small businesses who want to improve search traffic.

7. Hotjar

Best for: Tracking user behavior

Examples of plugins: Hotjar

What we like:

Hotjar tracks online behavior in a way that's easy to understand and use to improve your user experience. It offers videos that show you how users are using your website. You can check out visual heat maps or filter through behavioral analytics like time on site, clicks per page, and more.

If you want to improve conversions and engagement with your website, this plugin is key.

8. Adobe Acrobat

Best for: Edit, open, and create PDFs

Examples of plugins: Adobe Acrobat

What we like:

While it's easy to open a PDF on most computers, advanced PDF functions can be more of a challenge. If you're running a small business, the ability to build PDF templates, create fillable PDFs, and track PDF signatures is a huge time saver.

This website plugin is the industry standard for your advanced PDF needs.

How to Choose the Right Plugin

1. Focus on why you need to add plugins.

You may be hoping to fix a simple problem, like redirecting links from an old site to a new one. But most of the time you'll want to use plugins to solve a range of problems. So, it's a good idea to start by making a list of functions you need on your website, and then start looking for plugins.

2. Figure out if you can solve multiple problems with a single plugin.

While there are thousands of plugins, you don't want too many on your site. Too many plugins can impact site speed.

More plugins can also make your website more challenging to manage. This is because it makes it difficult to isolate which plugin might be causing an issue after an update. If you log in every day, this might not have an impact on your website, but if you have auto-updates or log in less often it can have a major impact on your site.

Recommendations for the max number of plugins range from four to 20+, but generally, less is more. With that in mind, review full features lists for each plugin as you search to avoid duplicate functionality and to get more with fewer plugins.

3. Search for your plugin.

There are many different ways to search for a plugin. If you're starting with your list, you can search online for each plugin individually, then compare features. If that's not working for you, user forums and talking to your network are good places to start.

As you build your website you might look at other sites for inspiration. These sites can also be a great source for plugins. BuiltWith Technology Lookup is a simple way to find out what tools a website is using.

What are plugins example: BuiltWith Technology Lookup example

Another way to figure out what plugins a WordPress site is using is by inspecting the page. Start with a website, then open the page source. Click Ctrl +F to search and type wp-content/plugins/. This will direct you to the plugins on that site.

4. Compare plugin options.

Once you have a list of plugins to consider, create a spreadsheet and start comparing. This can be a time-consuming process, so start with the functions that are most important to your team.

User reviews

Customer feedback can help you get a better idea about how a plugin works, what problems it solves, and how else this plugin might impact your site. Plugin reviews are often more critical than other types of reviews. They often contain helpful tips and things to look for, which makes them a useful place to start.

Update frequency

Software is constantly changing, and the best plugins get frequent updates to meet those changes. Some updates are small bug fixes, while others are big changes. Update frequency can tell you how invested developers are in a plugin and how long that plug will be effective.

For example, say you're comparing two plugins with 4+ ratings. If one hasn't had an update in two years and the other got an update last month, the plugin with the most recent update is a better choice.


Strong plugin support is essential for your user experience. Many projects seem simple at the beginning, and a general plugin can solve basic problems. But if you're using a plugin for your business, it's more likely that specific problems will come up that you can't solve on your own.

Great documentation and active support can save time and vastly improve your user experience.


There are many different factors that can impact plugin quality. This means that some plugins can create security flaws on your website. So, it's important to keep security in mind, no matter what kind of plugin you're looking for, and to scan reviews for mentions of potential security issues.

Review the FAQs

To round out your research, FAQ pages can help you dig into the details of a plugin. Whether you're hoping to solve an unusual problem or figuring out premium options, this section is a smart way to finish up your comparison.

This information can help you notice overlaps between plugins, compare pricing, and narrow down your list of plugins to try.

5. Install and test your plugin.

Finally, you want to install your plugin. This post has detailed instructions for adding plugins if you're still learning WordPress.

Once you add your new plugin, follow the instructions for set up, and do some tests to make sure it works the way you expect it to. While you may want to test similar plugins, try not to test more than one plugin at a time.

For example, if you're testing three different SEO plugins, don't add them all at once. Instead, add and test each plugin one at a time. Be sure to add some content to your site so you can see how each plugin really works.

With a few successful tests, you should be able to choose the right plugins for your business.

Plug and Play

Plugins make it easy to add functionality for desktop software, mobile applications, and even IoT applications.

To get the most from this plug-and-play potential, always err on the side of security. Don't add excess plugins and keep up with the lightweight code landscape for new plugins and updates.

With these tools, you can make the most of your software, no matter your level of tech ability.

Editor's note: This post was originally published in December 2020 and has been updated for comprehensiveness.

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