Immediate migration of complex TYPO3 legacy systems using Application Gateway
The migration of a content management system is one of the more demanding projects in digital transformation. Particularly in the case of mature TYPO3 installations with hundreds of extensions, individual customisations and years of history, changing the system becomes a challenge.
The problem with black box development
The traditional path of a CMS migration usually follows a familiar pattern: a project team develops the new system behind closed doors for months. Requirements are defined at the beginning, concepts are created, then development begins. Meanwhile, the old TYPO3 system continues to run and must be maintained in parallel. Every change to the content, every new function has to be implemented twice - once in the live system and once in the development environment of the new CMS. This black box development creates several critical problems. The development time drags on for months, while the business does not stand still. New requirements arise, priorities shift, but the project continues according to the original plan. At the end, there is the dreaded "jolt" moment: the go-live. A switch is made on a key date and suddenly it becomes clear whether everything is working - or not. Only now do real users get to see the system. Problems that were not noticeable in the test environment become apparent in live operation. Edge cases that nobody had thought of occur. Acceptance becomes a mammoth project because everything has to be tested at once.
The alternative approach: application gateway for step-by-step migration
There is another way. Instead of a big-bang relaunch, an application gateway enables a step-by-step, low-risk migration. The old and new CMS run simultaneously and functions are transferred to the new system step by step. Technically, this is realised using an application gateway. This infrastructure component sits in front of both systems and uses defined rules to decide which system is responsible for which request. Initially, the old TYPO3 system still serves the majority of the website. Then, for example, the homepage is migrated and played out via the new system. In the next iteration, other areas follow - the blog, then the product pages, and finally more complex functions such as forms or integrated applications. In the event of problems, an area can be quickly routed back to the old system without jeopardising the entire website. The application gateway acts as an intelligent intermediary that seamlessly harmonises session handling, cookie management and URL routing between the two systems.
Concrete advantages in everyday project work
Iterative approach even with complexity: instead of having to migrate everything at once, you can proceed according to priority and risk. Critical areas with complex extensions are tackled later, non-critical content pages first.
Gentle migration: The customer familiarises themselves with the new system step by step, training can be staggered. Editors familiarise themselves with new workflows step by step, while the old TYPO3 system only needs to be maintained for the remaining areas.
Without restrictions for users: the URL structure remains identical, the look and feel consistent. Nobody realises that two different systems are working in the background. This prevents confusion and negative effects on SEO rankings.
Flexible prioritisation: If it turns out during the migration that a certain area is more urgent than originally thought, it can be quickly rescheduled. New business requirements can be flexibly incorporated without having to overturn the entire project.
Technical implementation
In practice, various technologies are used as application gateways: Nginx with lua extensions, modern service meshes such as Istio, or specialised solutions such as Varnish, HAProxy or Traefik. The ability to route intelligently between backend systems based on URL patterns, header information or other request properties is crucial. Configuration is carried out via routing rules that define which paths are mapped to which system. These rules can be continuously adapted during the migration without causing downtimes, i.e. system failures.
Conclusion: Minimising risk through incrementality
CMS migrations of complex TYPO3 installations do not have to be high-risk projects. The typical stumbling blocks can be avoided with an application gateway and step-by-step migration. Real-world feedback comes early, problems are discovered and solved in manageable units. At Netresearch, we use this approach if the technical and organisational framework conditions allow it. Although the initial set-up of the application gateway infrastructure requires additional effort, this is quickly amortised through reduced risk, greater flexibility and better planning. The result is a migration that is not experienced as a feat of strength, but as a natural progression.
