Services

Application Modernization Services for Web and Mobile Products

Your application may still serve its users while becoming harder to change. A dependency update breaks the build, the team that knew the code has moved on, and even routine maintenance starts to feel risky.

Companies we've collaborated with

SLIDEFACTORY helps teams assess, repair, and modernize existing web and mobile applications. Our application modernization services are built for products with real users and real business value, including products that need a new technical foundation before the next feature can be delivered safely. We work through the code, integrations, tests, and release constraints, then recommend a practical path forward.

Signs your application needs attention

It no longer builds on current tools. Old SDKs, native projects, or build scripts require a developer’s aging laptop or a toolchain that is difficult to reproduce.

Updates have become risky. A small change produces unrelated failures, and the team lacks tests to show what broke.

Critical dependencies have fallen behind. The app relies on unsupported packages, old platform APIs, or libraries that no longer work with current requirements.

The original developers are unavailable. Important knowledge lives in undocumented code, lost credentials, or services the current team cannot access.

The app has several fragile integrations. Authentication, analytics, backend services, payments, hardware, or third-party APIs all need to keep working while the core application changes.

A release is difficult to reproduce. The difference between the repository, the local build, and the deployed application is unclear.

Assess the application before choosing a fix

You do not need to know which of these issues calls for a rebuild. The first task is to make the system understandable.

We start by reviewing the codebase and how the product is built and operated. That can include dependency and platform versions, build and deployment steps, tests, integrations, data flows, security issues, and the parts of the app that change most often. If the product does not build, reproducing and diagnosing that failure may be the first useful milestone.

The output is a written recommendation: which problems need immediate repair, which components can be upgraded in place, and which parts may justify replacement. We also identify major unknowns and propose a sequence that limits disruption. The scope and timing of an assessment depend on what is available, whether the application can be built, and how many systems it touches. We agree on its deliverables before work begins.

For an AI-generated or heavily AI-assisted codebase, we can combine human engineering review with CodeRaven, our code-review system. The objective is still a practical recommendation for the people maintaining the product, not a tool-generated score. Learn about AI code rescue.

Repair, move platforms, or rebuild?

There is no single answer for every older application. We compare the effort to stabilize what is there against the cost and risk of replacing it.

Repair and upgrade makes sense when the product’s structure is sound but its build tools, dependencies, tests, or a few integrations are holding it back. The goal is to preserve working behavior while removing the barriers to maintenance.

Move selected components when one platform or integration is the bottleneck. That might mean replacing a backend SDK, rebuilding native project files, or putting an older renderer behind an interface so it can be changed without rewriting the whole app.

Rebuild a larger portion when the architecture itself prevents the product from meeting current needs. A rebuild is a significant investment, so we define which existing behaviors and data must carry forward and which problems a new foundation solves.

The right option depends on the codebase, the product roadmap, and the cost of interruption. We make that decision from evidence gathered during assessment, then scope the work in stages.

What we modernize

Our team modernizes applications built with JavaScript, Node.js, Swift, C#, and PHP, including React Native and Expo mobile apps, React web applications, WordPress sites and custom plugins, and CakePHP projects. We also work on the backend services and APIs those products rely on. The work might involve updating dependencies and native projects, migrating integrations, improving code quality and test coverage, or making the build and deployment process reproducible for the next team that inherits it.

We also take on older Unity and C# application work where an upgrade, a narrower replacement, or a different rendering approach needs evaluation. For applications assembled with AI coding tools, the issue is often whether the code can be understood, tested, and changed safely as the product grows. See our AI code rescue service and Unity work. For new builds, see custom web application development and mobile app development.

Anonymous client example

An application that needed a new foundation

We inherited a mobile application whose code had been untouched for years. The original developers were gone, and the project would not build on a current development machine. Some of the supporting packages and service configuration were no longer readily available. Before new product work could proceed confidently, the application needed a reproducible build and a clear account of how its integrations behaved.

We rebuilt the native project using current Expo tooling and brought the existing application source into it. Across the work, we updated, replaced, or removed 67 dependencies and revised important backend and device integration code. We added a replay harness that sends recorded sessions through the real integration and analytics paths, making it possible to test behavior without relying on a physical device for every run.

We also expanded automated coverage from 26 test files to 56 suites with 326 passing tests. TypeScript errors went from approximately 186 to zero, while lint errors and warnings went from 51 and 48 to zero. That work exposed and fixed approximately 25 bugs already present in the application, including failures in a core integration. The codebase now builds and runs on a current iOS simulator.

326

Passing automated tests, up from 26 test files

TypeScript errors, down from about 186

Approximate count of preexisting bugs found and fixed

Dependencies updated, replaced or removed

Process

How a modernization engagement runs

How long this takes depends on the state of the application and how much of it needs to change. The assessment provides a basis for a timeline instead of a guess made before anyone has inspected the code.

Assess

We review the code, build process, dependencies, tests, integrations, and product priorities. We document the risks and recommend what to repair, move, or rebuild.

Stabilize

We establish a reproducible build and address blockers that prevent safe development. That may include restoring a missing dependency, updating configuration, or adding tests around behavior that must survive the migration.

Modernize in stages

We work through the highest-impact components in an agreed order, verifying existing behavior as tools and integrations change. This lets the client review progress and adjust later stages as we learn more.

Hand over or continue supporting

We document the system and the decisions made during the work. Depending on the engagement, we can hand the code to your team or continue with development and support.

Keep the product usable while the code changes

When an application already has users, the modernization plan needs to account for them. We identify the behaviors and data that must be preserved, test the areas most likely to break, and plan changes in stages. Release sequencing, testing environments, and a way to recover from a bad update should be defined for the specific product before changes reach users.

This is particularly important when an older app relies on backend services or native libraries. An update can appear successful on one developer’s machine while failing elsewhere. Reproducible builds and tests give the team a better basis for deciding when a change is ready.

Ready to make your application easier to change?

Tell us what the product does, where the team is stuck, and what you need to build next. We can help determine the first useful step.

Talk about your application

Frequently Asked Questions

How much does application modernization cost?

It depends on the state of the codebase, the number of integrations, and whether the right solution is repair, a targeted replacement, or a broader rebuild. We start with an assessment and scope the work around the risks and outcomes it reveals.

How long does it take?

A focused dependency or build repair can be much smaller than a platform migration or rebuild. We provide a timeline after examining the application and agreeing on the first stage, then adjust later stages as the work reveals more.

Should we rebuild or improve what we have?

We look at whether the current product can be made reliable and maintainable at a reasonable cost. If it can, improving it may preserve valuable working behavior. If core architectural problems keep blocking the roadmap, we will explain where a rebuild makes more sense.

Can you work with our developers?

Yes. We can assess a product and give your team a plan, take responsibility for a defined modernization phase, or collaborate through implementation and handoff. The responsibilities and review points are set in the project scope.

Do you need access to the original development team?

No. Their knowledge can help, but we can inspect the repository, reproduce the build, trace integrations, and document what we learn. Access to the code and relevant services is more important than access to the people who first wrote it.

Will users notice the modernization work?

That depends on what changes. Some improvements are behind the scenes; others involve a new interface or behavior. We define what needs to stay familiar, what should change, and how to verify it before any user-facing release is planned.