Plugin & Extension Development Services

Why build a custom plugin or extension

Most businesses run on platforms such as WordPress, WooCommerce, Shopify, Microsoft 365 or Atlassian. These platforms are designed to be extended. A custom plugin adds the feature you are missing — a booking flow, a pricing rule, an integration, an internal tool — without replacing the platform your team already knows.

A well-built plugin also replaces a stack of off-the-shelf add-ons that slow the site down, conflict with each other and each charge a monthly fee.

Platforms we build for

Off-the-shelf or custom?

We will tell you when an existing plugin is good enough — often the best solution is a well-chosen marketplace plugin plus a small custom extension.

How we build plugins that survive updates

• Platform standards — WordPress Coding Standards, Shopify app requirements, Manifest V3 for browsers.
• Hooks, not hacks — we extend through official APIs and never modify core or theme files.
• Security — nonces, capability checks, sanitisation and escaping, and least-privilege API scopes.
• Performance — assets loaded only where needed, cached queries and background jobs for heavy work.
• Compatibility — tested against current platform versions and popular companion plugins.

Our process

1. Requirements1 week

   Agree the feature, settings, user roles and integrations.

2. Build2–8 weeks

   Development in short sprints with a staging site for testing.

3. Test1 week

   Functional, security and compatibility testing.

4. Release & supportOngoing

   Deployment, documentation and updates when the platform changes.

Publishing to marketplaces

If you want to sell or distribute your plugin, we prepare it for the WordPress.org directory, the Shopify App Store, the Chrome Web Store or the Atlassian Marketplace — including listing assets, review requirements and licensing.

Maintaining plugins over time

A plugin is only as good as its last update. Platforms evolve constantly: WordPress releases major versions several times a year, Shopify retires API versions on a regular schedule, browser vendors change extension rules and Microsoft updates the Teams platform. A plugin that is never maintained eventually breaks or becomes a security risk.

We offer maintenance plans that track these changes for you: compatibility testing against beta releases, updates to new API versions before old ones are retired, dependency and security updates, and small improvements requested by your team. For commercial plugins sold to other businesses, we can also handle customer bug reports, release management and marketplace listing updates, so you can focus on selling the product.

Which platform should your extension target?

Many teams know the problem they want to solve but not where the extension should live. The right platform is the one your users already work in every day — an extension in a tool nobody opens will not be adopted, however good it is.

Private, unlisted or marketplace?

Before writing code, decide who will install the extension. The answer changes the architecture, the review process and the support burden.

Marketplace listings can be a meaningful source of customers, but they bring responsibilities: timely security fixes, compatibility with new platform versions, documentation and a support channel. We plan for those from day one rather than discovering them during review.

Architecture patterns that keep extensions healthy

• Thin integration layer. Keep platform-specific code in a small adapter and business logic in plain, testable modules — so a platform API change touches one place.
• Use official extension points. Hooks, webhooks, app bridges and published APIs survive updates; editing core files or scraping internal pages does not.
• Externalise heavy work. Long-running jobs, AI calls or large data syncs run on a separate service or queue, not inside a page request.
• Respect the host. Load scripts only where needed, cache sensibly and never slow down the store, site or workspace that hosts your extension.
• Plan settings and data cleanly. Clear settings screens, safe defaults and an uninstall routine that removes what the extension created.

A typical extension project

1. Discovery1 week

   Confirm the workflow, target platform, distribution model and the platform’s technical and review requirements.

2. Prototype1–2 weeks

   A working proof of the riskiest part — usually an API, permission or performance constraint.

3. Build & test3–8 weeks

   Feature development with automated tests across supported platform versions.

4. Review & release1–3 weeks

   Marketplace submission or private rollout, documentation and support setup.

5. MaintainOngoing

   Compatibility updates, security patches and improvements as the host platform evolves.

Timelines are typical ranges for a focused first version; marketplace review times vary by platform and are outside anyone’s control.

Questions to ask before you commission a plugin

• Does an existing, well-maintained extension already solve 80% of the problem?
• Which platform versions must be supported, and for how long?
• Who will own support and updates after launch?
• Will the extension store personal or payment data — and where?
• Is the goal internal efficiency, a client deliverable or a product to sell?

Pricing and monetising a public extension

If you plan to sell an extension, the business model affects the technical design. Licence checks, usage metering and plan limits are much easier to build in at the start than to retrofit.

Each marketplace has its own billing rules and revenue share. We check the current terms for your target platform during discovery so the model you choose is allowed and practical.

Supporting an extension after launch

An extension is a long-term commitment: the host platform will change, users will report edge cases and security issues must be handled quickly. A sustainable support set-up includes:

• A compatibility test suite run against new platform versions before they reach users
• Error reporting that respects privacy and the host platform’s policies
• Clear documentation and a changelog for every release
• A support channel with defined response times
• A security contact and a process for coordinated disclosure
• A deprecation plan if the extension is ever retired, so users are not left stranded

Taking over an existing plugin

We are often asked to rescue an extension built by someone who is no longer available. The first step is always a short audit rather than a rewrite: we review the code against current platform standards, check for security issues, confirm compatibility with the latest platform version and identify what is safe to change.

The audit usually ends in one of three recommendations — maintain and improve the existing code, refactor the riskiest parts, or rebuild on modern extension points while keeping data compatible. Each is a valid outcome; the right one depends on code quality, how much the extension still needs to change and how many users depend on it.

How to evaluate an extension developer

Extensions live inside someone else’s platform, so the developer must understand both your needs and the host platform’s rules. Ask:

• Which versions of the host platform will you support, and how will you test new releases?
• Do you follow the platform’s coding, security and review guidelines?
• How will settings, data and permissions be handled — and removed cleanly on uninstall?
• Who will submit to the marketplace and respond to review feedback?
• Will the source code, licence keys and marketplace listing be in our name?

For the most common platform, see WordPress plugin development.

Extension terms explained

What a typical extension project costs to own

Beyond the initial build, extensions need ongoing compatibility work as the host platform evolves. As a rule of thumb, plan for a few days of maintenance each time the host platform ships a major release, plus time for support requests if the extension is public. Private extensions used by one business usually need far less ongoing effort than marketplace products with many customers.

Cost

Typical ranges to help you plan. Your written estimate comes after a free discovery call.

Most of our plugin work is for WordPress — see WordPress plugin development. For complete stores, see eCommerce development.

Explore more in Software Development Services.