Create or optimise a website to drive your performance
An effective website must be visible, credible and easy to use, whatever the device. Castelis supports you in creating or optimising custom websites, designed for your users, technically high-performing and aligned with your communication and growth objectives.
When a website becomes a real performance driver
A poorly readable, poorly referenced or mobile-unfriendly site damages your image and effectiveness. Creating or redesigning a website aligns visibility, user experience and technical performance to meet visitor expectations and your business challenges.
Image and credibility
A site consistent with your positioning that reinforces confidence and the credibility of your organisation.
Enhanced visibility
Better presence on traditional and AI search engines through SEO and GEO foundations built in from the design stage.
Optimised conversion journey
Clear, goal-oriented user journeys to convert visitors into prospects or clients.
/ A structured approach to designing effective websites
Castelis takes a progressive and agile approach to designing high-performing websites, integrating usage, visibility and evolution challenges from the outset.
Scoping
Analysis of objectives, target audience, existing content and technical constraints.
Design
Definition of site structure, user journeys and UX/UI mockups.
Development
Site integration with particular attention to performance, SEO and accessibility.
Go-live
User acceptance testing, deployment, training and onboarding support.
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UX, performance and multi-device at the heart of web projects
A website must offer a consistent experience across desktop, tablet and mobile. Castelis designs responsive or mobile-first sites, integrating UX/UI best practices and performance standards to guarantee a smooth experience across all devices.
Mobile-first or responsive design
Clear, accessible user journeys
Load time optimisation
Compliance with accessibility standards (WCAG / EN 301 549)
Custom solutions for your digital growth
Castelis works on web development projects of all sizes. Whatever your context, we support your digital transformation projects with particular attention to their impact on growth, performance and the quality of your actions.
Institutional sites
Creation or redesign of showcase sites to enhance your image, structure your messages and strengthen your credibility.
Intranet / Extranet
Internal or partner web platforms to organise information, streamline exchanges and secure access.
E-commerce
Design of online sales platforms adapted to your commercial objectives and specific constraints.
Multi-site platforms
Deployment of shared structures to efficiently manage multiple sites from a common foundation.
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Sites designed to last and evolve
Sites developed by Castelis are built on modern technical choices, designed for performance, maintainability and evolution over time.
Modern architecture
Maintainability
Castelis: your usage and performance-driven web partner
We design websites combining strategic vision, UX/UI expertise and technical mastery, for useful, purpose-aligned projects.
End-to-end approach
From strategic thinking through to go-live and evolution.
UX/UI expertise
A strong focus on usage and user experience.
Technical mastery
Reliable, high-performing, scalable technical choices.
Agile methodology
An iterative approach promoting adaptation and cost control.
/ They strengthened their digital presence with Castelis
Discover how our clients improved their visibility, image and web performance through custom projects.
Groupe Leclerc | Security and performance of the e-commerce site
Unification of e-commerce and marketplace sales on a geo-redundant cloud platform.
Apave | Rationalising and optimising a large digital ecosystem
Deployment of a centralised digital platform to harmonise Apave's web presence across 45 countries.
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Your questions on website creation and optimisation
When the site no longer reflects your image, is no longer performing, poorly referenced or unsuited to current usage. An analysis by our experts will determine whether you need a full redesign or targeted optimisations.
By jointly working on content, technical performance and user experience. These levers are complementary and must be considered together to improve natural search rankings and your conversion rate.
Yes, sites designed by Castelis are built to evolve easily, both in terms of content and functionality.
Let's talk about your project
