How To Add "License Key" When Creating Wordpress Plugin

Every WordPress site needs a theme to pull content from the database and brandish that in a design. And theoretically you could run a site with just a theme and nothing else. But that site would be very limited without the addition of plugins.

Plugins add extra functionality to your WordPress site over and to a higher place what comes with WordPress core. Everything from a booking calendar or animated slider to a full-featured learning management organization or online marketplace—you can add them all to your site with plugins.

In this guide, I'll show you how to create your own WordPress plugin. I'll show you how to use best practice in plugin development, how to get the lawmaking in your plugin to run, and how to structure your plugin'south code and files. I'll also walk you through the procedure of creating your first plugin and answer some FAQs.

Costless and Paid WordPress Plugins

If you lot desire to add some specific features to your website, in that location are plenty of places yous tin buy or download plugins. The WordPress plugin directory includes thousands of free plugins that'll help you create the site y'all need. But if you lot're looking for more avant-garde features, a better user interface, or improved back up, it's worth buying premium plugins from authors on CodeCanyon.

But sometimes you might need to code your own plugin! This tin exist more than efficient than using a third-party plugin, as you might only need a role of the lawmaking provided by those. It also ways you can develop a plugin that meets your needs more precisely, or you can customise an existing plugin to arrange information technology for your site.

What Do Y'all Need to Brand a Plugin?

To build your own plugin and run it on your WordPress site, you'll need:

a lawmaking editor
a evolution WordPress installation with a copy of your live site for testing

Don't exam your plugin on your alive site until you know it works!

If you don't already take a local WordPress installation, follow our guide to copying your site to a local install. Or if you can't install WordPress locally, use a indistinguishable of your site on a testing installation on your server. Find out how to copy your site.

Types of WordPress Plugin

Plugins tin can behave out lots of tasks. What they all accept in common is that they add extra functionality to your site. Types of WordPress plugin include:

site maintenance plugins for things like security, functioning, or backups
marketing and sales plugins for things similar SEO, social media, or eCommerce
content plugins such as custom postal service types, widgets, shortcodes, forms, galleries, and video feeds
API plugins that work with the WordPress Residuum API or pull in external content from services like Google Maps
community plugins that add social networking features

… and lots more! For an idea of what plugins can exercise, check out the WordPress plugin directory and the CodeCanyon market place.

What Goes Into a Plugin?

Before you get started edifice your plugin, it'due south worth knowing what goes into a plugin. Exactly what the plugin lawmaking will expect similar will depend on your plugin: some are small, with simply one plugin file, while others are massive, with multiple include files, scripts, stylesheets, and template files. And there are plenty that autumn somewhere in the middle.

The elements you'll probably accept in your plugin are:

the main plugin file (this is essential)
folders for different file types
scripts
stylesheets
include files to organise the code

Let's have a expect at each of these.

The Principal Plugin File

The main plugin file is essential. It will always exist a PHP file, and it volition always comprise commented-out text that tells WordPress almost your plugin.

Here's an example, from the Akismet plugin:

<?php  /**   * @bundle Akismet   */  /*  Plugin Name: Akismet Anti-Spam  Plugin URI: https://akismet.com/  Description: Used by millions, Akismet is quite mayhap the best fashion in the earth to <strong>protect your blog from spam</strong>. It keeps your site protected fifty-fifty while y'all sleep. To get started: activate the Akismet plugin and and so go to your Akismet Settings page to fix up your API key.  Version: four.i.7  Writer: Automattic  Writer URI: https://automattic.com/wordpress-plugins/  License: GPLv2 or afterward  Text Domain: akismet  */

This tells WordPress what your plugin does, where to find out more about it, and who developed it. It also gives information nigh the version number and the text domain and path for internationalisation, as well as the license.

WordPress takes this information and uses it to populate the plugins screen in your site. Hither'south how Akismet looks on that screen:

Yous tin can run into that the information provided in the plugin file is used to populate this entry and provide links.

Other information near the plugin is independent in theREADME.txt file, which is used to populate the plugin's page in the plugin directory:

The main plugin file will besides comprise the lawmaking that makes the plugin run. Sometimes that will exist all the PHP for the plugin, just for larger plugins, in that location'll be calls to include files containing extra lawmaking. This helps you organise your lawmaking and means you don't accept i long, disorganised file that's hard to piece of work with. I'll show you how to utilise include files subsequently in this guide.

Folder Structure

While at that place are no hard and fast rules on how you organise the folders in your plugin, it makes sense to prefer the same structure that other plugin developers use. This volition familiarise you with the way other plugins are built and hateful that if you lot share your code in time to come, it volition make sense to other people.

Folders in your plugin might include:

css orstyles for stylesheets
scripts for JavaScript
includes for include files
templates for template files that your plugin outputs
assets for media and other asset files
i18n for internationalisation files

You might find you demand to utilise more folders if your plugin is big or circuitous. For instance, WooCommerce has folders for packages, sample data, and more than. These in plough include subfolders for things like blocks and admin files.

Scripts and Stylesheets

If your plugin outputs content that needs styling, either in the forepart-finish or in the admin screens, y'all may need stylesheets. And if your plugin volition use scripts, you'll need files for these.

It makes sense to continue these in their own binder, even if you lot only accept one of each. You'll need to enqueue these scripts and stylesheets using a dedicated function in your main plugin file. I'll prove you how to exercise this when we're building the plugin.

Include Files

If your plugin needs organisation, you can do this by splitting your code into multiple files, called include files. You then put these files into their own binder and call them in your master plugin file using aninclude orrequire function.

This way, you tin can keep the bulk of your code in a well-organised file structure while your main plugin file remains lean and minimal.

If your plugin isn't all that big, you don't demand to apply include files: but add together your code to the primary plugin file. But you might find y'all need to organise this file and reorder functions inside it as you add together them, to maintain a logical structure.

These are the most common elements of a plugin. We've seen in the WooCommerce instance that there tin can be many more. Or in smaller plugins there can be many fewer. But as you lot develop more plugins, you'll find yourself using these elements more and more than.

How to Run Your Plugin Code: Options

When you add lawmaking to your plugin, it won't do anything until you activate it in some style. There are a few methods y'all can utilise to activate your lawmaking or pull in code from WordPress:

functions
activeness and filter hooks
classes

Permit's take a await at each of these.

Functions

Functions are the edifice blocks of WordPress code. They're the easiest mode to get started writing your own plugins and the quickest to code. You'll detect plenty of them in your themes' files too.

Each function volition have its own name, followed by braces and the code inside those braces.

The code inside your plugin won't run unless you phone call the office somehow. The simplest (but least flexible) manner to do that is past directly calling the code in your theme or somewhere else in your plugin.

Here'due south an case function:

tutsplus_myfunction {  // lawmaking goes hither  }

To directly phone call that function in your theme, you lot'd simply blazontutsplus_myfunction() in the place in your theme template files where you want it to run. Or y'all might add it somewhere in your plugin... only you'd also need to activate the lawmaking that calls it!

There are a few limitations to this:

If the function does something that isn't just adding content somewhere in a theme template file, you tin can't actuate information technology this way.
If yous want to call the role in multiple places, you lot'll take to call it again and again.
It tin be hard to keep rails of all the places yous've manually chosen a role.

It's much better practice to call functions by attaching them to a hook.

Activity and Filter Hooks

By attaching your function to a hook, you run its code whenever that hook is fired. There are two types of hook: activeness hooks and filter hooks.

Activeness hooks are empty. When WordPress comes to them, it does zero unless a function has been hooked to that claw.

Filter hooks contain code that will rununless in that location is a function hooked to that claw. If there is a function, it'll run the code in that office instead. This means you lot tin add together default code to your plugin merely override it in another plugin, or y'all tin can write a office that overrides the default lawmaking that's attached to a filter hook in WordPress itself.

Hooks are fired in 3 means:

By WordPress itself. The WordPress core lawmaking includes hundreds of hooks that fire at dissimilar times. Which one you hook your function to will depend on what your function does and when you desire its code to run. You tin observe a list of WordPress hooks in the programmer handbook.
Past your theme. Many themes include activeness and filter hooks that you lot tin can use to add extra content in key places in your website'southward blueprint. And all themes volition include awp_head andwp_footer claw. Combine these with conditional tags, and y'all tin run specific code on certain types of pages in your site.
By your plugin or other plugins. You might add an action hook to your plugin and then add together functions in your include files that attach lawmaking to that claw. Or yous might write a filter hook and then take a office that overrides its contents under certain circumstances. Alternatively, if yous're creating a plugin to complement another plugin, y'all tin hook your functions to the existing hook in the third-political party plugin. I've done this with WooCommerce, for example, to customise what's output on product pages.

Some of this is more avant-garde, but with your first plugin, you'll probably exist hooking your functions to an action or filter claw output by WordPress itself, nearly likely an action hook.

Classes

Classes are a way of coding more complex features, such as widgets and customizer elements, that make use of the existing WordPress APIs.

When you lot write a class in your plugin, you'll probably exist extending an existing class that's coded into WordPress. This way, you tin can brand use of the code provided by the class and tweak information technology to make information technology your own. An example would be the customizer, where y'all might write a form including a color picker, making use of the color picker UI that's provided in the existing class for the customizer.

Using classes is more advanced than functions, and it's unlikely yous'll do information technology in your get-go plugin. To find out more, encounter our guide to classes in WordPress.

If you do write classes, y'all'll all the same take to use actions or filters to get them to run.

Plugin Best Practices

Before yous start coding your plugin, it helps to understand best practices for plugins so your lawmaking tin be high quality right from the first.

These include:

Write your lawmaking according to WordPress coding standards. If you lot desire to submit your plugin to the plugin directory, you lot'll have to do this.
Use comments throughout your lawmaking and then other people can work with it—and and so you remember how your lawmaking works when you come back to information technology in the time to come.
Name your functions, hooks, and classes using prefixes and then they are unique to your plugin. You don't want to give a part the same proper name as some other function in a different plugin or in WordPress core.
Organise your folders logically, and keep your lawmaking separated so other people tin can understand it and and so you tin add to it over fourth dimension without it becoming a mess.

You lot might think that using best practice isn't necessary considering information technology's just you working with the plugin. Simply your plugin might grow over time, you might let other people employ it, or you might sell it. Or yous might come back to information technology in ii years and not exist able to remember how the code is organised!

Creating Your Beginning Plugin in iv Steps

At last! Yous accept a grounding in how plugins piece of work, and it'southward fourth dimension to roll your sleeves upward and create your showtime plugin. I'm going to accept yous through the process of creating a simple plugin that registers a custom post blazon.

This is a very common use of a plugin, and something you might then build on over fourth dimension to add custom template files for your custom post type or other functionality.

I'll prove y'all the basic code for the plugin and requite you an introduction to how you might add to information technology over time.

1. Create the Plugin Folder and File

Even if your plugin is starting out small with just one file, information technology'south expert practice to give it its ain binder. Start past creating a folder in yourwp-content/plugins directory. Within that, create a PHP file for your plugin.

Give them both a name that makes sense and includes a prefix. I'm calling my foldertutsplus-register-postal service-types and my filetutsplus-register-mail-types.php.

Now open your plugin file and add the commented-out information at the height. You can take mine below and edit it to reflect the fact that this is your plugin, not mine.

<?php  /*  Plugin Proper noun: Tuts+ Register Post Types  Plugin URI: https://tutsplus.com/  Description: Plugin to accompany tutsplus guide to creating plugins, registers a post type.  Version: 1.0  Author: Rachel McCollin  Author URI: https://rachelmccollin.com/  License: GPLv2 or later  Text Domain: tutsplus  */

Now, if you save your file and become to thePlugins screen in your development site, you'll see the plugin on the screen:

You can activate it if you want, but it won't do anything yet because you oasis't added any lawmaking to it. Let's do that.

2. Add together Functions

Now it's time to write the first function in our plugin. Start by making your plugin and adding the braces which will contain the code. Here's mine:

office tutsplus_register_post_type() {      // movies      $labels = array(           'name' => __( 'Movies' , 'tutsplus' ),          'singular_name' => __( 'Moving-picture show' , 'tutsplus' ),          'add_new' => __( 'New Moving picture' , 'tutsplus' ),          'add_new_item' => __( 'Add New Movie' , 'tutsplus' ),          'edit_item' => __( 'Edit Picture' , 'tutsplus' ),          'new_item' => __( 'New Movie' , 'tutsplus' ),          'view_item' => __( 'View Movie' , 'tutsplus' ),          'search_items' => __( 'Search Movies' , 'tutsplus' ),          'not_found' =>  __( 'No Movies Found' , 'tutsplus' ),          'not_found_in_trash' => __( 'No Movies establish in Trash' , 'tutsplus' ),      );      $args = array(          'labels' => $labels,          'has_archive' => true,          'public' => true,          'hierarchical' => imitation,          'supports' => array(              'title',               'editor',               'extract',               'custom-fields',               'thumbnail',              'page-attributes'          ),          'rewrite'   => assortment( 'slug' => 'movies' ),          'show_in_rest' => true      );  }

This includes all the labels and arguments for your mail type and (crucially) theregister_post_type() function which is provided by WordPress.

I've used movies every bit my post type here as I'm creating an imaginary film review site. You might want to employ something different.

Now, if you save your file and go dorsum to your site, you'll see that zip has changed. That's considering you haven't activated your code. The method we use to activate the function here is by hooking it to an action hook provided by WordPress, theinit hook. When you use a function provided by WordPress (such asregister_post_type), you lot'll find that there'south a hook that you should apply. You tin can discover details in the WordPress handbook entry for registering custom mail service types.

So let's add together the hook. Under your code, and outside the braces, add this line:

add_action( 'init', 'tutsplus_register_post_type' );

We use theadd_action() function to hook our code to an activity hook, with 2 parameters: the proper noun of the activeness hook and the name of our function.

Now try saving your files and going back to your site. You'll see that the custom post type has been added to your admin menu (assuming you lot've activated the plugin).

Prissy!

Now let'south add together an actress part, to annals a custom taxonomy. Below the code you've written so far, add together this:

function tutsplus_register_taxonomy() {               // books     $labels = array(         'name' => __( 'Genres' , 'tutsplus' ),         'singular_name' => __( 'Genre', 'tutsplus' ),         'search_items' => __( 'Search Genres' , 'tutsplus' ),         'all_items' => __( 'All Genres' , 'tutsplus' ),         'edit_item' => __( 'Edit Genre' , 'tutsplus' ),         'update_item' => __( 'Update Genres' , 'tutsplus' ),         'add_new_item' => __( 'Add New Genre' , 'tutsplus' ),         'new_item_name' => __( 'New Genre Name' , 'tutsplus' ),         'menu_name' => __( 'Genres' , 'tutsplus' ),     );           $args = array(         'labels' => $labels,         'hierarchical' => true,         'sort' => true,         'args' => array( 'orderby' => 'term_order' ),         'rewrite' => assortment( 'slug' => 'genres' ),         'show_admin_column' => true,         'show_in_rest' => true       );           register_taxonomy( 'tutsplus_genre', array( 'tutsplus_movie' ), $args);       } add_action( 'init', 'tutsplus_register_taxonomy' );

Once again, you might want to alter the name of your custom taxonomy. Here, I've made the taxonomy utilize to the mail service type I've just registered (the tertiary parameter of theregister_taxonomy office). If you gave your mail type a different name, make sure to edit that bit.

Now save your file and take a look at your admin screens. When you hover over your post blazon in the admin menu, you'll run across the new taxonomy.

You now take a working plugin. Well done!

Let'due south have a expect at how you might add to information technology.

3. Enqueue Stylesheets and Scripts

If y'all need to use custom styling or scripts in your plugin, you could add together them right into your plugin file—but that's not all-time practice. Instead, yous should create stylesheets and scripts as carve up files in your plugin folder and enqueue those, using a function provided by WordPress.

Let's imagine you lot desire to add styling for your custom postal service type. Y'all could add this to your theme, but you might want to add some specific styling to the plugin to make the post type stand out from other postal service types in whatsoever theme.

To practise this, yous create a new binder inside your plugin folder calledcss (orstyles, information technology'southward up to y'all). Inside that binder, create a stylesheet calledstyle.css, or you can give it a more specific proper noun for clarity. I'm going to call minemovies.css.

Y'all then need to enqueue that file in your plugin and so that it can be used past WordPress. Add together this to your primary plugin file, above the functions you already have. I like to add together enqueuing and includes first in my plugin file and then I can see what other files are being activated.

office tutsplus_movie_styles() {     wp_enqueue_style( 'movies',  plugin_dir_url( __FILE__ ) . '/css/movies.css' );                       } add_action( 'wp_enqueue_scripts', 'tutsplus_movie_styles' );

If you save your file, y'all won't see any difference in your admin screens—but if you lot've added posts of the custom post blazon and your stylesheet includes styling for them, you'll now run across that in the front-terminate of your site.

Note that the hook used for enqueuing both stylesheets and scripts is the aforementioned: they both usewp_enqueue_scripts. There isn't a separate hook for styles.

Enqueuing scripts works in a very similar style. Follow these steps:

Add together ascripts orjs folder to your plugin binder.
Salve your script files in that folder.
Enqueue the script in the same way as the stylesheet above, replacing thewp_enqueue_style() office withwp_enqueue_script().

four. Using Include Files

Another option every bit y'all develop your plugin is to create extra PHP files, known as include files. If you take a lot of these, you lot might create multiple folders for different types of include file, or you lot might just create one folder chosenincludes.

There are a few functions you lot tin use to include files, which you'll find in our comprehensive guide to including and requiring files.

For example, in our custom postal service type plugin, we might create some code to vary the manner the content of the folio is output, using thethe_content filter hook to amend the code being run each time the content is output on a product page.

Instead of calculation this code to the chief plugin file, y'all could add it to a separate file calledmovie-content.php and then write the lawmaking in that file for the fashion the content is output for movies.

To include this file in your plugin, you add together a folder calledincludes to your plugin, and so inside that binder you add thecontent-movie.php file.

To include that file in your plugin, you lot add this code at the commencement for the principal plugin file:

include( plugin_dir_path( __FILE__ ) . 'includes/movie-content.php' );

You lot don't need to hook this to an action or filter hook—just use theinclude_once() function in your plugin file. That volition then call the lawmaking from the include file as if it was in your chief plugin file at that bespeak.

How to Extend or Edit an Existing Plugin

Sometimes you might notice a plugin in the plugin directory or from a plugin vendor that does most of what you need a plugin to do, simply not quite all. Or you might be running a plugin and want to make some tweaks and customisations.

The fact that WordPress is open source makes this possible. You can take another plugin's code and extend or edit it to make information technology work the way you want it to.

There are ii means to do this:

Take an existing plugin and fork it—i.due east. edit it then it works differently, is more reliable, or has actress features.
Write your own plugin that extends the original plugin.

Taking an existing plugin and editing it is fairly straightforward: yous brand your own copy on a development site (never live!) and make edits to it every bit needed. Make certain you use version control to track your changes in instance something goes incorrect.

Extending a plugin by writing your ain plugin is slightly more complicated, and won't work with every plugin, but is a more robust way of doing things in my opinion.

Many of the nigh popular plugins will make all-encompassing utilise of hooks and classes in their lawmaking. You can hook into action and filter hooks and extend classes to write your own code, which uses the existing plugin's code as a base of operations simply then adds to or edits it.

For example, WooCommerce has and then many functions, hooks, and classes that information technology has its own API and programmer documentation. Each part of the WooCommerce system is powered by one or more of these functions, hooks, or classes. To brand changes, you need to place which code is driving the office of the system you want to change, and and so write your own plugin which either attaches to the aforementioned hook(due south) or extends the classes.

You'll find you tin create significant customisations to a plugin like WooCommerce in this mode: I once used information technology to power a listings site that didn't even include a checkout. I used hooks to remove all the elements I didn't want and add new ones.

For some examples of how you lot can hook into WooCommerce and extend or edit it with your ain plugin, come across our guide to adding product descriptions to archive pages and to adding a product-based blog to your store. These examples just scratch the surface of what yous can achieve, but they'll give y'all an idea of how to get-go.

Taking It Further: Plugin Features

In this guide, I've shown you how plugins are coded and how to get started building a simple plugin.

One time you've got the hang of plugin development, yous can build more than circuitous and full-featured plugins to bear out more complex tasks on your site.

Permit's take a look at some examples.

Widget Plugins

Widget plugins involve working with classes but are a skillful introduction to the topic. Our guide to creating a widget plugin will help yous do information technology.

You can also find plenty of widget plugins on CodeCanyon, which will save yous coding them yourself. On our blog, nosotros've identified the best widget plugins for 2021, the all-time Facebook widgets, and the all-time Twitter widgets.

Shortcode Plugins

Creating a shortcode is a slap-up place to first creating plugins as they're relatively simple and very useful. Find out how to create them with our guide to coding shortcodes in WordPress.

CodeCanyon likewise has a bunch of useful shortcode plugins you lot can use to add together extra functionality to your site.

Social Media Plugins

Social media plugins are incredibly popular as they let you brandish your Facebook, Twitter, or Instagram feed on your site and let your visitors share your content via their own social media accounts.

CodeCanyon has dozens of social media plugins. Learn most the best social media plugins and how to create an online community for your WordPress site.

Gallery and Media Plugins

If you want to optimise the media on your site and display galleries or video feeds, a plugin will make everything expect more than professional. Find out how to find the all-time gallery plugins for images or video and how to code your own gallery plugin. Or browse the professional gallery and video plugins on CodeCanyon.

Class Plugins

Adding forms to your site lets your visitors get in touch and helps build a relationship. CodeCanyon has plenty of premium class plugins that volition make information technology easy for your visitors to contact you. Learn how to create a course with the bestselling QuForm plugin.

FAQs

Hither are the answers to some of the most frequently asked questions about WordPress plugins.

Why tin can't I just add together the code I need to my theme functions file?

Information technology's tempting to simply continue on adding code to thefunctions.php file, and there is some code that should exist there.

But if your code is related to functionality in your site, rather than the blueprint or the output of content, and then you should lawmaking information technology into a plugin. This ways that if you switch themes in the future, you still have that functionality. And y'all tin can utilize the plugin on some other site running a different theme.

I've added code to my plugin. Why is nothing happening?

This is probably because you oasis't hooked your code to an action or filter hook. Until yous do that, nix will happen.

When I edit my plugin and check my site, I get a white screen. Help!

Yous've probably added some code that's got an error in it somewhere. PHP is an unforgiving language, and this might be equally pocket-sized as a semicolon in the wrong place.

Try turning onWP_DEBUG in yourwp-config.php file, and y'all'll see a bulletin telling you where the error is. Then you can ready it.

When I activate my plugin, I get an mistake message telling me likewise many headers have been output. What does this mean?

All this commonly means is that there are likewise many empty lines in your plugin file. Get back and bank check at that place are no empty lines at the start of the file.

If that doesn't fix it, endeavour turning onWP_DEBUG.

Where can I find out more about developing plugins?

We accept lots of tutorials and courses helping yous to build all kinds of plugins hither on Envato Tuts+. See if yous can detect anything that inspires you lot.

Where can I download plugins for my site?

You can choose from thousands of gratis plugins in the WordPress plugin directory. You lot can also buy third-party plugins from CodeCanyon. Always buy plugins from a reputable supplier so you can be sure they follow WordPress coding standards and don't contain malicious lawmaking.

Summary

Plugins will plough your site from a simple blog into a powerful website that includes advanced features and is secure and robust. Try adding plugins to your site today and coding your own to see how you can use plugins to meliorate your WordPress site.

The Best WordPress Themes and Plugins on Envato Market

Explore thousands of the best WordPress themes ever created on ThemeForest and leading WordPress plugins on CodeCanyon. Purchase these loftier-quality WordPress themes and plugins and improve your website experience for you and your visitors.

Hither are a few of the acknowledged and up-and-coming WordPress themes and plugins available for 2020.

Did you lot observe this mail service useful?

Rachel McCollin

WordPress Programmer and Writer, Birmingham Uk

Rachel McCollin is a WordPress developer who writes books, articles and tutorials about web design and development, with a focus on WordPress and on responsive and mobile evolution. She runs a web blueprint agency in Birmingham, Uk and has published three books on WordPress, including WordPress: Pushing the Limits, an avant-garde resource for WordPress developers. She'southward currently writing her 4th book.