Being open source software, WordPress has really helped communities and developer resources. A short of list of useful WordPress developer resources have been listed here, Hoping that these resources will help you to speed up your development efficiency.

1. Developer WordPress Reference

If you ever wanted to know what’s going on inside WordPress and it’s code. Which functions, hooks, APIs, Classes and methods are being used, this is should be your go-to place. You can search this Code Reference for more information about WordPress’ functions, classes, methods, and hooks. Upon clicking them you get to see sources of these functions, hooks. With each WordPress version, it gets updated so you can be sure of its authenticity and relevancy, a perfect theme development resource.

2. WPmail.me

You should always keep yourself up to date with the latest WordPress news. Hence, I’m recommending wpmail.me . It is a free WordPress newsletter that sends you an email once a week and has been operating for a long time. With a round-up of WordPress news and articles. A great source to stay up to date with WordPress eco-system.

3. WordPress Plugin Boilerplate

It’s a WordPress plugin boilerplate designed to ease your plugin kick start process. A standardized, organized, object-oriented foundation for building high-quality WordPress Plugins.

• It’s a Boilerplate is based on the Plugin API, Coding Standards, and Documentation Standards.
• All classes, functions, and variables are documented so that you know what you need to be changed.
• The Boilerplate uses a strict file organization scheme that corresponds both to the WordPress Plugin Repository structure, and that makes it easy to organize the files that compose the plugin.
• The project includes a .pot file as a starting point for internationalization.

You can contribute to this open source project in GitHub.

4. WordPress Plugin Boilerplate Generator

A project of Enrique Chavez, This plugin boilerplate generator is based http://wppb.io . As Enrique was using WordPress Plugin Boilerplate, every time he has to search and replace plugin name, sub packages names etc. Hence he built this boilerplate generator. You just need to fill up the plugin name, plugin slug, plugin URI, author name, author URI and author email fields.

5. Generate WP

A great tool to generate custom codes for WordPress. You fill up a form with information regarding function name and other necessary parameters depending upon the type of generator you use, And then you click the “update code” button to generate the code for you. Generators are divided into –

1. Admin

1.1 Toolbar Generator
1.2 Quicktags Generator
1.3 oEmbed Providers
1.4 User Content Method Generator
1.5 Dashboard Widgets Generator (Premium)

2. Content

2.1 Shortcode Generator
2.2 Post Type Generator
2.3 Meta Box Generator (Premium)
2.4 Taxonomy Generator
2.5 Term Meta Generator (Premium)
2.6 Post Status Generator

3.Core

3.1 Hooks Generator
3.2 wp-config.php Generator
3.3 Plugin Readme Generator
3.4 Schedule Cron Job Generator
3.5 Register WordPress Scripts
3.6 Register WordPress Styles

4. Design

4.1 Menu Generator
4.2 Sidebar Generator
4.3 Widgets Generator (Premium)
4.4  Theme Support Generator
4.5 Theme Default Header Generator

5. Query

5.1 WP_Query Generator
5.2 WP_User_Query Generator
5.3 WP_Comment_Query Generator
5.4 WP_Term_Query Generator
5.5 WP_Site_Query Generator
5.6 WP_Network_Query Generator
5.7 WP_Meta_Query Generator
5.8 WP_Data_Query Generator

6. General

6.1 Custom Generator

A lot of custom snippets have shared in this Snippet section might also be useful to you, pretty useful WordPress developer resource.

6. WordPress Plugin Template

A project of Hugh Lashbrooke, A robust code template for creating a standards-compliant WordPress plugin. Some of the features of this plugin template are

• Full & minified Javascript files
• Grunt.js support
• Standard enqueue functions for the dashboard and the frontend
• A library for easily registering a new post type
• A library for easily registering a new taxonomy
• A complete and versatile settings class

7. WordPress Reference

Prepared by the DBS Development team, It’s basically a reformatted Template Tag section of the WordPress.org Codex. Great for quick reference from of WordPress, Kinda encyclopedia to WordPress theming, and a great reference for your WordPress developing questions. The DBS web development team created this quick reference guide to expedite their WordPress theme development and found it so useful that they thought to share it. You get WordPress tags and their parameter description just the way you see it Codex except it’s been reformatted in a cleaner way.

8. WP REST API

With REST API introduction in WordPress 4.7 it is now more important than ever to know about REST API. This is the official WP REST API website. You have Glossary, Change log, User guide, Common problems, Compatible plugins and tools, API reference. Also extending API references such as –  modifying responses, adding endpoints, hooks references and all the things you need to know about WP REST API under one roof.

9. WP Rollback

For people out there suffering for their theme/plugin update, this could be your solution. It quickly and easily rollbacks any theme/plugin from WordPress.org to any previous/newer version without any of the manual FTP stuff. It works exactly like the plugin/theme updater, except for the fact that you’re rolling back/forward to a specific version. With this handy plugin, you can say goodbye to your update fear. WP Rollback just cuts down the manual downloading and FTPing the files or learning Subversion or any other complex kinds of stuff and takes care of the trouble for you.

Do check out their GitHub Wiki Page for more information. And as always use this plugin in a staging environment or make a backup copy of your site. Definitely, a must use among many WordPress developer sources.

10. Github Updater

If you want to update your themes/plugins from GitHub, this could be your go-to plugin. Github Updater enables automatic updates to your GitHub, Bitbucket, or GitLab hosted WordPress plugins, themes, and language packs. It also allows for the remote installation of plugins or themes. The plugin also has a Slack channel – Slack team for GitHub Updater and click here for an invite.

• Requires at least: 4.0
• Requires PHP: 5.3
• Tested up to: 4.7
• Stable tag: master

In order for this plugin to work your plugin/theme must contain a header in the style.css or in the plugin’s header denoting the location on GitHub. Check the Github page for the header format and more information.

11. Poststatus.com

A go-to site for news & information for WordPress professionals. Starting from Matt Mullenweg interview to core team updates and follow up on new topics, everything is covered in Post Status.

12. WP Test

If you ever felt like the regular dummy demo content to test your theme was not enough. Well, guess what! you’re not alone. Created by Michael Novotny and acquired in September as Post Status Labs Project, WP Test is a fantastically exhaustive set of test data to measure the integrity of your plugins and themes.

This test data comes packed with lessons learned from over four years of theme and plugin support, and baffling corner cases, to create a potent cocktail of simulated, quirky user content. WP Test still offers the following benefits over the WordPress Unit Test data, such as –

• Transparency

WP Test comes with release notes indicating what has been added, removed, or changed within the data for each release, which Codex Theme Unit Test doesn’t provide.

• Contribution & Community

Contributing to the WordPress Codex is fairly straightforward, but contributing to the test data is not. By using GitHub to host the WP Test data, anyone is free to contribute to the project in a multitude of ways.

• Guided Help

Not only is the WP Test data content funny, but it’s also smart and helpful. Whenever possible, the test data references the WordPress Codex for best practices and function references. These kinds of integration into the test data will only increase over time and lessen the barrier to resolving the issues the test data uncovers.

You can download this dummy content and update it manually or you can install it via WP-CLI.

13. Fakerpress

Unlike the theme test unit, If you want to create content as you develop this plugin can help.  It lets you create various types of dummy contents on the fly.

14. WP CLI

A command-line based tool for managing WordPress installations. You can update plugins, configure multi-site installs and much more, without using a web browser. The main goal of this plugin is to provide a command-line interface for any action you might want to perform in the WordPress admin. It also includes commands for many things you can’t do in the WordPress admin, such as – deleting all the transients.

15. 10up Engineering Best Practices

10up is well versed in the WordPress ecosystem and is well known for specializing in WordPress enterprise solutions. Following their footsteps would do nothing but help you in your WordPress coding journey. From markup to project structure all most everything has been mapped out.

16. Codepoet

An AUTOMATTIC Medley, You can browse videos by categories such as – CSS, Theme Dev, Plugin, Security, SEO, Business, Client Service. You can also check out the articles, resources and books page for more WordPress resources.

17. Mattreport

Podcast site focused on WordPress freelancers, agency owners, product creators, craving actionable advice. You get industry news, interviews and advice from renowned WordPress developers, Which will definitely help you to understand the ecosystem better.

18. Include WP

Powered by Freemius, All the top, open-sourced plugin and theme frameworks, starter themes and plugin boilerplates in once place. These frameworks are pulled GitHub so do the stats of each framework. All frameworks are open sourced. You can sort and view these resources by their GitHub stars, Forks, Issues and name.

19. Hookr.io

You get a list of all the hooks (Action/Filter), Classes, Constants, Function used in WordPress. These sections are alphabetically organized. With each section have a usage section and where it has been used in WordPress along with version number. You can download the free Hookr plugin for your own development purpose. Hookr plugin feature includes –

• Augments pages to illustrate which actions & filters run during the page life cycle
• Inspecting  filters
• Details of every hook
• Built-in lucene search engine for fast filtering
• Tweak settings options to suit your development workflow
• Provides what file & line(s) the code/object is defined, also any related hook callbacks sharing the same tag name or signature.
• Dynamically generated usage blocks are available for every action, filter, function & constant
• hyperlinked & annotated source code blocks to find what you need

20. WPSeek

Another WordPress tool, geared toward developers and theme authors. You type your query on the search box and AJAX powered search result will be shown in the list. You can search through functions, filters, actions, and constants. More information such as – where these functions are used in WordPress software since when it was added to WordPress can be also found. And the good thing is wpseek is very much updated and maintained. On top of all these features. You have extra goodies like –

Plugin Doctor – Check your plugin for deprecated functions. Check what WordPress version is required based on the functions used. Upload files from Box.net, Dropbox, Google Drive, Github, and your local computer.

Plugin Slug Availability Check – Check for the plugin name your want use.

You also get jQuery API plugin, Ubiquity plugin, Sublime Text Plugin, and an Android app.

21. WordPress.tv

Another good resource for savvy WordPress users. You get how videos, videos from renowned WordPress people,  Interviews from popular WordPress professionals and videos from WordCamp.

22. Adam Brown’s WO Hooks Database

A collection of all the hooks used in WordPress by Adam R Brown. Right from WordPress 1.2.1 to WordPress 4.4 all the hooks were documented in this website.

22. WP Glossary

WP Glossary is a side project by Anders Norén. WP Glossary contains definitions of most of the words you come into contact with when you’re using WordPress. It’s built for anyone who spends time in the WordPress administration panel, whether you’re a professional using it as part of your job or someone who has a personal WordPress blog. The definitions are short and to the point.

23. WP Settings API

Created by Jeroen Sormani, You can create your plugin/theme setting page using this tool. All you need to do is type your plugin/theme name, prefix and text domain. And then on the “Setting” tab you get this default WordPress dashboard area and on the right you have type of setting you want to create. It’s all drag and drop, so you can drag and drop text field, checkbox, radio button, text area or select option. Then just click the Let’s go button and all the code will be generated for you. Additionally, you have options to display the menu in a menu page,  Sub-menu page, not in the menu and options page.

24. WordPress.Stackexchange

http://wordpress.stackexchange.com/ is purely focused on WordPress. It’s a question & answer community for all WordPress development-related questions.

Final Thoughts

Even though this is not a comprehensive list but I believe some of these WordPress developer resources will be useful to you and your development team. However, if you’re still new to WordPress and wondering how to get started with it, here is a useful resource that will help you learn WordPress and its best practices. What are the resources you personally use and prefer? Do you want to include any other cool resources I haven’t mentioned? Do let me know in the comment section or shoot me a Tweet, if they’re really helpful I will add them in.