Contao CMS Development The open-source CMS for clean, accessible websites
SMEs, associations, organisations — when clean code, accessibility, and data protection aren't nice-to-haves but core requirements, Contao is the right choice. Built on Symfony, Contao delivers structured, standards-compliant websites that score equally well with users and search engines. As an experienced Contao agency, we've been building accessible web solutions for the Swiss market for over 20 years.
The CMS that writes clean code — not bloated markup. Semantic HTML, built-in accessibility, Symfony foundation. Built for quality. That means: clean output, structured content, and no dependency on dozens of plugins.
While other CMS platforms rely on plugin ecosystems for basic functionality, Contao delivers clean, semantic HTML and accessibility features out of the box. Built on the Symfony framework, Contao combines modern PHP architecture with an intuitive backend for editors. At Sidora, we deploy Contao where clean code quality, accessibility, and maintainability are non-negotiable — especially for Swiss SMEs, associations, and organisations that value substance over complexity.
Three pillars. One goal: Contao as your clean, accessible web platform.
We design Contao websites that combine editorial flexibility with accessible, standards-compliant output. Clean markup, logical structure, and beautiful design.
Accessible templates
Contao templates with semantic HTML, ARIA labels, and structured headings — accessible from the start, not bolted on afterwards.
Multi-language support
Native multilingual content management with language fallbacks, separate page trees per language, and locale-specific navigation.
Responsive layout framework
Contao's layout system with themes, page layouts, and CSS framework integration for consistent, responsive designs across all devices.
Custom content elements
Tailored content elements and modules beyond the standard set — precisely fitted to your editorial workflow and content strategy.
Editor-friendly backend
Clear backend structure with intuitive content areas, drag-and-drop article management, and visual page preview for editors.
From custom Symfony bundles to seamless integration with your existing business systems — we build what your project needs.
Contao extension development
Custom Contao extensions as Symfony bundles — cleanly structured, testable, and following Contao's coding standards.
REST API & headless integration
Contao as a content backend with REST API for modern frontend frameworks like React, Vue.js, or Next.js.
ERP/CRM integrations
Seamless integration with your business systems: Abacus, Bexio, Salesforce, or Microsoft Dynamics via standardised interfaces.
Form & workflow automation
Custom form processing, notification workflows, and automated data handling via Contao's form generator and Symfony events.
Composer-based deployments
Modern deployment workflows with Composer, CI/CD pipelines, and automated releases for secure and reproducible deployments.
Outdated Contao installations or legacy CMS systems are a security risk. We migrate your website — without data loss, without downtime.
Contao 3.x/4.x to 5.x upgrades
Structured migration of older Contao versions to 5.x with compatibility checks, extension updates, and Symfony migration steps.
Relaunch of existing installations
Modernisation of existing Contao websites with new design, updated templates, and optimised content structure.
Migration from other CMS
Import and transformation of content from WordPress, Joomla, TYPO3, or proprietary CMS into Contao — with clean data mapping.
Performance optimisation
Analysis and optimisation of load times, database queries, caching strategies, and asset delivery for existing Contao installations.
Technical debt reduction
Code audit, refactoring of outdated extensions, and cleanup of legacy issues for a future-proof Contao foundation.
Your website deserves a CMS that puts clean code and accessibility first
Let's analyse together whether Contao is the right platform for your requirements. In a no-obligation consultation, we'll clarify your goals, evaluate your needs, and outline a realistic project framework.
From requirements analysis to go-live: Structured and transparent
Requirements Analysis
We analyse your existing infrastructure, define target audiences, content structure, and integration requirements. The result: a detailed specification that serves as the foundation for all subsequent steps.
Architecture & Concept
Based on the specification, we design the Contao architecture: page structure, theme framework, extension landscape, and deployment strategy. For multilingual projects, we define language trees and fallback logic.
Design & Prototyping
Our design team creates the user interface — accessible per WCAG 2.1 AA and optimised for all devices. Interactive prototypes enable early feedback before a single line of code is written.
Development & Integration
Contao templates, Symfony bundles, backend configuration — our development team implements the architecture in a staging environment. Parallel code reviews and automated tests ensure quality.
Testing & QA
Functional tests, accessibility audit (WCAG), performance benchmarks, and security scans. Only when all criteria are met do we approve the deployment.
Go-Live & Training
After go-live, we train your editors in the Contao backend. We create tailored documentation and stand ready during the hypercare phase for rapid adjustments.
Proactive protection for your Contao investment
A Contao installation requires regular maintenance: core updates, extension updates, security patches, and performance monitoring. Our maintenance packages ensure your website remains stable, secure, and performant — so you can focus on your content.
Standard
For Contao websites with standard requirements and moderate traffic.
- Contao core updates & patches
- Monthly security scan
- Uptime monitoring
- 2h support contingent
Professional
For business-critical Contao websites with priority support and extended monitoring.
- Contao core updates & patches
- Weekly security scan
- Uptime + performance monitoring
- 5h support contingent
- Extension updates included
- Staging environment
Enterprise
For organisations with high demands on availability and support.
- Everything from Professional
- SLA: 4h response time
- Dedicated contact person
- 10h support contingent
- Proactive optimisation
- Priority emergency hotline
Technological excellence behind our Contao solutions
Backend
Frontend
Infrastructure
Tools
Security by design: Clean architecture, Swiss hosting, full compliance
Contao's Symfony foundation provides enterprise-grade security out of the box. Combined with our Swiss hosting infrastructure and hardened configuration, your website meets even the strictest data protection requirements.
Security Architecture
nDSG Compliance
Violations of the nDSG can result in fines of up to CHF 250,000. We ensure your Contao project is compliant.
Contao for SMEs and larger organisations
SMEs
For companies with 5 to 200 employees that need a clean, accessible website with structured content management. Contao grows with your business — without unnecessary complexity or bloat.
Professional quality without enterprise overhead
Organisations & Associations
For associations, educational institutions, and larger organisations that need multilingual content, structured workflows, and accessibility compliance. Contao handles complexity cleanly.
Accessibility, multilingual, and fully compliant
Contao for organisations that value clean code and accessibility
Contao is the CMS of choice for organisations that prioritise accessibility, clean markup, and long-term maintainability. We understand the specific challenges of these industries — and know how Contao solves them.
Associations & NGOs
Associations, federations, and non-profits rely on Contao for accessible, multilingual web presences with member areas and event management.
Education & Training
Schools, universities, and training institutions use Contao for structured course catalogues, event calendars, and accessible content for all learners.
Hospitality & Tourism
Hotels, restaurants, and tourism organisations benefit from Contao's multilingual capabilities and clean mobile-optimised output for international guests.
Healthcare
Medical practices, clinics, and health organisations trust Contao for accessible, privacy-compliant web presences with physician directories and appointment booking.
Trades & Manufacturing
Craft businesses and manufacturers use Contao for professional web presences with project portfolios, service catalogues, and clean SEO fundamentals.
Professional Services
Law firms, consultancies, and agencies rely on Contao for structured, professional websites with clean code and excellent performance.
Retail & E-Commerce
Shops and retailers use Contao with Isotope eCommerce for product catalogues, online shops, and seamless integration with payment and shipping providers.
Public Administration
Municipalities and public institutions choose Contao for accessible, standards-compliant web presences that meet government accessibility requirements.
Contao Trends 2025/2026
Contao 5.x
The latest major release brings Twig templates, improved content elements, and full Symfony 7 compatibility. We migrate your installation to the newest version.
Headless Contao
With the Contao Headless Bundle, Contao becomes a pure content API. Frontend frameworks like Next.js or Nuxt deliver the interface — for maximum flexibility and performance.
Accessibility (EAA)
From 2025, digital accessibility is legally required in the EU. Contao has prioritised accessibility from day one — we ensure your website fully meets WCAG requirements.
Symfony Ecosystem
Contao benefits directly from Symfony's security updates, performance improvements, and the vast ecosystem of Symfony bundles — a future-proof foundation for any web project.
Your Contao agency in Switzerland
Over 20 Years of Experience
Since 2003, we've been building digital solutions for the Swiss market. We know the CMS landscape inside and out — and know exactly when Contao is the right choice.
Accessibility Experts
Contao and accessibility go hand in hand. We implement WCAG 2.1 AA as standard and ensure your website is usable for everyone — not just for compliance, but by conviction.
Swiss Hosting
All projects are hosted on Swiss servers — ISO 27001-certified, nDSG-compliant, and with guaranteed data sovereignty.
Personal Support
With us, you have dedicated contacts who know your project. No anonymous ticket system — direct communication at eye level.
Full-Service Agency
From strategy through design and development to ongoing operations — everything from a single source. This reduces friction and accelerates your project.
Open-Source Commitment
We believe in open source. Contao is community-driven, transparent, and free from vendor lock-in — values we share and actively support.
Frequently Asked Questions About Contao CMS
The most important answers about Contao development, costs, and project requirements — concisely summarised.
Ready for a CMS that puts clean code and accessibility first?
Let's talk about your Contao project. We advise you without obligation and show you how Contao solves your requirements — technically clean and future-proof.