Legacy Application Modernization
Services

It depends on the size of the legacy frontend and how much of it is coupled to the backend. A focused UI modernization or a single-module migration usually takes 4-8 weeks. A full AngularJS-to-Angular or Angular-to-React migration of an enterprise product runs 3-6 months and ships in increments, so the first modernized module is in production long before the last one. The assessment fixes the scope, and the proposal that follows it fixes the timeline per phase.

Yes, and it is the default rather than an option. We never do a big-bang cutover. The legacy and the modernized parts run side by side behind one shell and one router, each module is migrated, tested and released on its own, and feature flags let you switch a screen back if something is wrong. Users keep working in the old UI until the new version of that screen is ready; they never see a maintenance page.

We decide per module, not per product. Refactoring wins when the framework is still supported and the structure is salvageable: the code is restructured in place while the product keeps its behaviour. A rewrite wins when the stack is end of life (AngularJS, jQuery-era code) or when the logic is so tangled that untangling it costs more than rebuilding it. Most legacy products end up with a mix, and the assessment tells you which modules fall on which side. The factors we score are the same ones in our frontend refactoring cost formula.

After the discovery call we review the codebase, the designs and the backlog, usually with a short technical audit, and send a proposal within 3-5 business days. The estimate is built from five factors: how tied the frontend is to legacy libraries, how coupled it is to the backend, the state of tests and releases, whether a knowledge keeper is still around, and how much logic lives in each screen. Fixed-scope phases get a fixed price; dedicated teams are billed monthly. We do not publish rates, because the right team depends on the product; the call is where we work that out together.

In most modernization projects the backend stays where it is and we modernize the frontend against the existing APIs, adding a thin adapter layer where the old contracts are awkward for a modern UI. When backend constraints block a framework switch, we modernize the UI inside those constraints and structure the code so the switch is cheap once the backend catches up; the reward platform example above is exactly that case. We can take backend and API work when a project needs it, but the frontend is what we are hired for and where we are strongest.

AngularJS (1.x) and early Angular versions, jQuery, Backbone and Knockout frontends, server-rendered UIs on ASP.NET, JSP or PHP templates, React apps built on old class components, and Bootstrap-era interfaces with no design system. The targets are Angular, React or Next.js in TypeScript, with a component library and tests. If your stack is not on this list, the assessment will tell us quickly whether it fits.

Usually yes. A legacy screen rebuilt pixel for pixel keeps the workflows users complain about, so our SaaS design team reworks the flows and builds the design system in the same sprint in which the engineers migrate the code. If your product already has a design system, we build on it instead of replacing it.

Three ways: we own the frontend modernization end to end as a project, we run a dedicated team that you steer, or individual senior engineers join your squad and your process. In every model your team keeps the product direction and the architecture decisions, works in its own repositories from the first commit, and owns the code. Knowledge transfer is part of the delivery, so your engineers can maintain the modernized product without us.