Development of a custom WordPress plugin or theme

Installing a premium theme and a few extensions is often enough to get started.
But as soon as your site becomes a genuine business tool – interfacing with a CRM, complex subscription logic, specific back office, customised workflow – the limitations of generic solutions become apparent.

This page describes a standard project case managed by Evolurise: the development of custom WordPress plugins and themes, designed to precisely meet your functional, technical and business needs, while remaining maintainable, efficient and secure.

Why switch to bespoke solutions?

You may be in one of the following situations:

• You have accumulated too many plugins to circumvent the limitations of existing tools.
• You are dependent on a key plugin that is no longer being developed, or whose support is becoming uncertain.
• Do you require a specific business function (calculation, workflow, API integration) not found in the ecosystem.
• Your current theme is hindering the site's development: poor performance, inflexible templates, significant technical debt.
• Your CIO/CISO is requesting a more controlled, auditable, documented.

The challenge is no longer simply to “add a feature”, but to design a custom WordPress brick who:

• integrates seamlessly into your ecosystem,
• complies with WordPress standards,
• either testable, maintainable and extensible over several years.

The business and technical challenges of a custom plugin/theme

A project of custom WordPress development concentrates several types of issues.

Business challenges

• Translate specific business logic (rate calculation, file management, complex forms, scoring, approval workflow, etc.) into a clear functionality for your teams.
• Interface with your existing systems (ERP, CRM, business tools, third-party services) via robust API integrations.
• Ensure that the site remains aligned with your internal processes, not the other way around.

Technical challenges

• Respect the Core WordPress standards (hooks, filters, plugin structure, internationalisation).
• Avoid conflicts with other extensions or core updates.
• Anticipate future needs (expansion of scope, multi-site, multi-language, etc.).
• Ensure adequate performance, even in the context of heavy traffic or large databases.

Long-term challenges

• Document what is developed so as not to depend on a single person.
• Plan a strategy for maintenance and updates.
• If necessary, be able to open part of the code (open source, private plugin shared between several sites within the group).

Two types of projects

Custom WordPress plugin development

We work on custom plugins for:

• Business plugins
  • file management, requests, bookings, registrations,
  • internal workflows (validation, notifications, export).
• Custom WooCommerce plugins
  • complex pricing rules,
  • specific subscription systems,
  • advanced discount or commission schemes,
  • customised payment or delivery gateways.
• API integrations & connectors
  • synchronisation between WordPress and your CRM (HubSpot, Salesforce, Pipedrive, etc.),
  • connection to an ERP, an invoicing tool, a marketing automation solution,
  • Exposure of clean APIs (REST endpoints) for other internal applications.

Each plugin is designed as a stand-alone brick, featuring:

• a clear configuration space,
• a clear separation between business logic and presentation,
• hooks enabling future extensions.

Custom WordPress theme development

For some projects, the theme is a strategic element:

• institutional website with high image requirements,
• portal or intranet with complex templates,
• multi-site/multi-brand architecture where the front consistency is key.

We design bespoke themes:

• Aligned with your charter : Customised UI/UX, consistent design system, reusable components.
• Designed for content editors :
  • integration with Gutenberg (custom blocks),
  • or construction with a page builder if justified, but controlled,
  • block and template logic that facilitates the work of marketing/communication teams.
• Optimised for performance :
  • selective loading of resources,
  • Clean HTML/CSS,
  • good foundation for Core Web Vitals.

Where relevant, we separate the logic into:

• parent theme (main brick, design system),
• children's themes to develop several websites from the same base.

Technical approach: a modern, clean and scalable WordPress

We treat WordPress as a framework in its own right, and not just as a CMS that needs to be adapted with plugins.

Our approach includes:

• Strict compliance with WordPress coding standards (WordPress Coding Standards).
• Systematic use of hooks, actions, filters to prevent excessive overloading.
• Code structuring in modules, classes, services when the context is appropriate.
• Integration of modern solutions:
  • custom Gutenberg block,
  • ACF (or equivalent) for structured fields,
  • REST API for exposing or consuming data.

We also attach particular importance to:

• at the’internationalisation (i18n, l10n),
• at the role and capability management WordPress,
• compatibility with environments multi-environment (dev / pre-production / production).

Examples of project scenarios

Scenario 1 – Business plugin for a complex form and workflow

• Requirement: a multi-step form for collecting complex files, with internal validation and export to a business tool.
• Solution: development of a custom plugin managing:
  • the form (front),
  • data storage (custom post types / dedicated tables),
  • the approval workflow (roles, statuses, notifications),
  • exports (CSV, API).

The result: a structured business tool that is fully integrated with the WordPress back office.

Scenario 2 – Advanced WooCommerce plugin for subscription logic

• Requirement: subscription model that does not fit into the standard plugin categories (specific billing cycles, conditional access rights, renewal rules).
• Solution: customised WooCommerce plugin, interfaced with the chosen payment gateway, managing:
  • creating and updating subscriptions,
  • suspension/resumption,
  • rights to reserved content,
  • customer notifications.

The result: a distinctive business model, supported by a reliable technical foundation.

Scenario 3 – Customised theme for an institutional portal

• Requirement: redesign of a complex institutional website with numerous types of content and a strong need for SEO/performance.
• Solution: custom WordPress theme, based on a consistent design system, combining:
  • templates for news, resources, events,
  • Gutenberg blocks dedicated to content teams,
  • Seamless integration with existing plugins (SEO, cache, forms).

The result: a high-performance, manageable website where editorial teams gain greater autonomy.

Quality, safety, maintenance: thinking about the “day after”

A custom plugin or theme should not be a “one-off”.
Evolurise integrates from the outset:

• Versioning (Git) : versioned code, clear history.
• Test environments : non-regression testing during Core updates or major extensions.
• Targeted tests : verification of critical cases (payment, registration, document generation, etc.).
• Minimum technical documentation : structure, extension points, deployment procedures.
• Integration possible with our services:
  • SLA & WordPress Maintenance,
  • IT outsourcing & hosting for comprehensive control.

Objective: for your custom plugin or theme remains an asset, and does not become a technical debt.

Coordination with other Evolurise projects

The development of custom plugins and themes is often part of a larger package:

• Website creation When requirements go beyond the standard framework, a custom theme and a few tailor-made plugins enable the creation of a perfectly adapted platform.
• Online shop creation Advanced WooCommerce plugins for logistics, subscriptions, pricing, and B2B.
• AI Workflows & Automations WordPress extensions that trigger or consume external workflows (Make, Zapier, AI API).
• Intranet/extranet : themes and plugins for structuring business interfaces, partner portals, and customer areas.

You therefore benefit from a sole partner for the design, development, operation, and evolution of your WordPress solutions.

Let us discuss your specific requirements

Have you identified a critical feature that cannot be properly covered by existing plugins?
Is your current theme hindering your progress or performance?
Are you considering a business plugin or a custom WordPress theme and you require senior advice?

Share with us:

• the functional scope of your requirement,
• the plugins/themes you use today,
• your technical constraints (hosting, security, performance).

We will then be able to offer you a structured, tailor-made development project :
architecture, costing, planning, and support (maintenance, upgrades) to ensure that your WordPress brick becomes a true business lever, not just a simple technical fix.