Plugin development and custom extensions
Plugin development means adding a specific feature to software you already use, without replacing it. From Bastia, we build plugins, custom extensions, templates and digital resources, for your own teams or for sale to other users.
Plugins, extensions and templates: what are they?
A plugin, or extension, is a module that attaches to existing software to add a feature: a website, a browser, an office suite, professional software or a development environment. The host software provides the framework; the extension supplies what you are missing.
Templates and digital resources are ready-to-use building blocks: document or page templates, interface components, rule sets, reusable code libraries. They save time for whoever uses them and can be a product in their own right.
The benefit is twofold: you keep the tool your team already knows, and you only pay to develop the feature that makes the difference.
Custom extensions: examples by sector and tool
- 01
Websites and online shops
A booking module, specific order fields, a link to your management software, or shipping costs calculated by your own rules, including for parcels sent from Corsica to the mainland.
- 02
Browser
An extension that picks up information from the pages you visit and sends it to your customer database, or adds shortcuts to an online tool you use all day.
- 03
Office suite and email
A module that fills in a document from your data, files certain emails or adds a button that opens your business software.
- 04
Professional software
An extension for design, management or accounting software, where its publisher allows it.
- 05
Development and AI tools
Feature Workflow, one of our own projects, is a plugin that gives an AI coding agent a structured development workflow: feature definition, analysis, planning, implementation, review, testing and documentation.
- 06
Local authorities and networks
Document and page templates shared between several organisations, such as neighbouring municipalities in Haute-Corse, to keep communications consistent and save time.
Building and selling plugins, templates and digital resources
An extension or template can also become a source of revenue. If you know a trade inside out, you know what the tools in your sector are missing, and that know-how can be sold as a digital product.
Several commercial models are possible: one-off sale; a licence, meaning permission to use the product under set terms such as the number of sites, the duration or the updates included; a subscription; or pay-per-use. The right choice depends on your audience and on what the product costs to maintain. We design the product, its activation and update system, and help you prepare it for your own online shop or for marketplaces, the online catalogues where users of a piece of software find its extensions.
How your plugin development project unfolds
- 01
Understand
The host software and its version, the feature you need, who will use it, your budget and timeline; for a commercial product, the target audience and the sales model.
- 02
Design
A study of what the host software allows, interface mock-ups approved before development, and an architecture that limits the impact of future host updates.
- 03
Build
Development and testing on the relevant versions of the host software, then a trial version installed in your environment so you can approve it in real conditions.
- 04
Launch and support
Installation or publication, documentation, compatibility tracked as new host versions come out, and further improvements.
Compatibility, security and ownership of an extension
- 01
Dependence on the host software
An extension lives at the pace of its host: after every major update, it has to be checked that it still works. Best to plan for this from the start.
- 02
Security
A poorly written extension can open a hole in an entire website or application. It should request as few permissions as possible, validate the data it receives and be kept up to date.
- 03
Data
If the extension reads or sends data, especially personal data, you need to know which data, where to and how it is protected, in line with GDPR.
- 04
Marketplace rules
Extension catalogues set their own terms: review before publication, payment rules, possible commission.
- 05
Intellectual property
For a product you sell, the quote states who owns the code and under which licence it is distributed.
What drives the cost of a plugin or extension
We do not give a price without understanding your needs; your quote breaks down these factors in plain language.
- 01
The feature itself
A small addition to a page, or a full module with its own settings screens.
- 02
The host software
The quality of its documentation, and what its extension system allows and restricts.
- 03
Connections
Data to exchange with your other tools or with online services.
- 04
Versions to support
A single version of the host within your company, or every version your future customers might run.
- 05
Commercial release
Licensing, activation, automatic updates, documentation and user support.
After release: maintaining your extension over time
An extension's life really begins once it is released. We follow new versions of the host software, fix reported bugs, apply security patches and add the features users ask for. For a commercial product, we can also host the licensing and update system, and help you answer your users' questions.
Technologies and methods
- TypeScript
- JavaScript
- Browser extensions
- Website modules
- APIs
- Licensing and activation
Frequently asked questions
Will an extension slow down my website?
A well-designed extension has a limited impact: it loads only what is needed, only where it is needed. We measure performance before and after installation.
What happens when the host software is updated?
Most updates have no effect, but major versions may call for adjustments. As part of maintenance, we test the extension on new versions and adapt it where necessary.
Can you modify an existing extension?
Yes, if its licence allows it and the code is accessible. It is sometimes safer to build a complementary extension than to change someone else's, as your changes would be wiped out by its next update.
Will I be able to sell the extension you build for me?
Yes, if the ownership terms in the quote give you those rights, which we agree together before work starts. We can also prepare the publication, the licensing system and the documentation.
Do I need an extension or a complete piece of software?
If your existing tool suits your team and only one feature is missing, an extension is often the most economical answer. If you are constantly working around the tool, custom business software may be the better fit. We will help you decide.