WordPress plugin development is writing custom PHP functionality packaged as a standalone plugin — independent of your theme, surviving theme changes and WordPress core updates without modification. I build custom post types with admin UI, custom REST API endpoints and webhooks, custom admin tools and settings pages, third-party API connections (Xero, Stripe, HubSpot, Salesforce), custom WooCommerce extensions, and anything else that requires functionality no existing plugin covers. All plugins are built to WordPress Coding Standards (WPCS) and documented for future maintenance.
Who it's for
What's included
How the process works
Define the spec
We agree exactly what the plugin needs to do, its admin UI, the data it stores, and any external API connections — documented in a spec before a line of code is written. No scope surprises.
Build on staging
Plugin built and tested against your real site environment — your active theme, plugin stack and PHP version — not in isolation. Edge cases and conflict points identified during build, not after delivery.
Review & revise
You test the functionality against the spec. I fix edge cases and any behaviour that doesn't match expectations in a single revision round.
Handover & deploy
Plugin delivered with full documentation — hooks, filters, settings — and pushed to your version control repository. Deployed to production when you're ready, with rollback available via Git.
Common questions
Yes — this is the primary reason to build a custom plugin rather than putting functionality in a theme's functions.php. A plugin is decoupled from the active theme: it survives theme switches, theme updates, and child theme changes without modification. It also survives WordPress core updates because I build to WordPress Coding Standards (WPCS), using the documented plugin API (hooks, filters, the Settings API, the WP REST API) rather than relying on internal WordPress functions that change across major versions. For PHP version compatibility, I target PHP 8.0–8.3 as the current supported range and test on the PHP version your host uses.
Yes — for small additions, extending via a companion plugin (also called an add-on or extension plugin) is cleaner than modifying the original plugin's core files, which get overwritten on update. A companion plugin hooks into the parent plugin's documented hooks and filters to add or change behaviour without touching the parent's code. For larger changes — adding new post types, entirely new admin screens, or functionality the parent plugin's hook system doesn't expose — a new standalone plugin is usually the right approach. I'll recommend the correct option after reviewing the parent plugin's hook documentation.
Yes. Custom WooCommerce development frequently requires plugin-level work: custom product types (beyond WooCommerce's built-in simple, variable, grouped and external product types), custom checkout fields with product-specific conditional logic, custom shipping method classes, custom payment gateway implementations for non-standard payment providers, and custom WooCommerce admin reports. All WooCommerce extension development follows WooCommerce's documented extension guidelines and uses the WooCommerce hooks API rather than overriding core WooCommerce classes directly, so the extension survives WooCommerce major version updates. See also my WooCommerce development service for store builds that include custom extensions.
Yes. Custom WordPress REST API endpoints are a common plugin development request for headless WordPress setups (WordPress as a content API consumed by a React, Next.js or Vue.js front-end) and for mobile apps that need to read or write WordPress data. I build custom REST routes using the WordPress REST API register_rest_route() function, with proper authentication (WordPress application passwords, JWT Authentication for WP-API plugin, or custom authentication headers), custom capability checks, JSON schema validation for request payloads, and rate limiting where needed. Custom endpoints can expose any WordPress data — custom post types, ACF fields, custom database tables — in whatever JSON structure the consuming application needs. If you also need the WordPress site to consume external APIs, I scope both directions (incoming and outgoing) in the same plugin build.
The plugin code is delivered to your version control repository (GitHub, Bitbucket, or your preferred host) with documentation, so you or another developer can make changes independently. For ongoing changes, I offer post-delivery support under my monthly care plan (which includes a development change allocation each month) or as individual scoped change requests. Because the plugin is built to WordPress Coding Standards with documented hooks and filters, adding new functionality typically involves adding new hook callbacks rather than modifying existing functions — a well-structured plugin is easy to extend safely.