15 Best App Refactoring Companies (2026)

Gilzor works with existing web and mobile products that have architectural problems, performance limitations, unstable components, or code that has become difficult to extend. Its modernization work includes architecture refactoring, critical module rewrites, recurring error resolution, unit testing, and improvements to older product structures. Gilzor has also documented the modernization of an established Android marketplace, where its engineers replaced an outdated application foundation while preserving important product workflows. The company can begin with a mobile app audit when the main question is whether an application should be repaired, stabilized, refactored, or rebuilt.

Itransition provides application modernization services that cover both focused code improvements and wider architectural changes. Refactoring is offered as a distinct modernization option, with engineers reviewing and restructuring existing code while preserving core functionality. The company also handles re-architecting, containerization, application migration, and functionality updates, so refactoring can be combined with infrastructure or platform changes when technical debt is not limited to the codebase. Its process begins with assessment of architecture, dependencies, documentation, and legacy code before a modernization approach is selected.

OSKI Solutions works with inherited and aging codebases that need to become easier to change without a large replacement project. Its legacy software modernization process starts by mapping dependencies, data, code quality, and technical risks, then stabilizing the existing application before deeper changes are introduced. Incremental refactoring is a defined part of the service, alongside framework upgrades, re-platforming, architecture changes, testing, and integration modernization. The team works with technologies including .NET, C#, Angular, React, Node.js, SQL Server, Umbraco, GraphQL, Docker, and Azure.

ScienceSoft handles application modernization projects involving code refactoring, technology migration, reengineering, re-architecting, cloud migration, and user interface updates. Its published modernization work includes legacy applications with incomplete documentation as well as systems that need individual technical components replaced without interrupting ongoing operations. One documented ride-hailing project involved converting legacy PHP code to Java, consolidating databases, reviewing existing code, and improving maintainability. ScienceSoft also has experience with C++ and Qt application refactoring, making its scope broader than web modernization alone.

A-listware combines application development and software modernization with dedicated engineering teams and long-term support. Its mobile development practice explicitly includes modernization through architectural redesign and code refactoring, while its broader software development offering covers legacy software modernization, cloud applications, QA, and maintenance. This creates several possible entry points for refactoring work, from improving a specific mobile application to updating a larger legacy product and its supporting infrastructure. Testing services include functional, performance, security, usability, and accessibility work.

Intellias treats refactoring as one of several paths for modernizing legacy applications. Its application modernization services cover replacement, replatforming, re-architecting, and refactoring, including projects where monolithic applications need to move toward more modular or microservices-based designs. A published fintech project describes refactoring a legacy monolith into microservices while maintaining the existing functionality and business logic. Intellias also handles cloud and data migration, integration modernization, and application landscape assessment, which is useful when code restructuring is connected to a wider platform transformation.

Mobian works on existing software through legacy integration, backend development, application maintenance, and modernization projects. Its delivery model is relevant when refactoring is tied to connecting an older system with new mobile applications, APIs, cloud infrastructure, or automation functionality. The company emphasizes clean architecture, documented code, full-stack delivery, and continued technical support after launch. Its published modernization material also describes work involving backend restructuring and replacing older components with maintainable modules while keeping critical workflows operational.

Merixstudio provides software modernization services with multiple approaches depending on how much of an existing application needs to change. Its published modernization framework includes an "augment and refactor" path between simple cloud relocation and a complete rewrite. The company also lists legacy application code refactoring within its enterprise software development services and develops modernization roadmaps for larger platforms. Its project portfolio includes mobile app modernization, which adds experience with client-facing products as well as business applications.

net-devs provides legacy modernization for enterprise software and explicitly avoids making a full rewrite the default strategy. Its process includes AI-assisted codebase analysis and modernization planning, while senior engineers retain responsibility for architecture, trade-offs, code review, and production decisions. The company describes AI as useful for areas such as analysis, refactoring, and documentation, with human review applied to delivered work. This model suits existing systems that need structured technical debt reduction, architecture improvement, or gradual modernization while remaining in production.

Softura offers application refactoring and re-architecting within a broader legacy application modernization practice. Its modernization model assesses existing applications and then selects among strategies such as rehosting, refactoring, re-architecting, rebuilding, or replacing. Refactoring is used to reorganize existing code and improve maintainability, performance, and adaptability, while more extensive projects can introduce microservices, cloud-native infrastructure, containers, or new architecture. Softura also supports application portfolio assessments, making it suitable for organizations with several aging systems rather than a single codebase.

SoftPro develops and modernizes applications with a strong focus on Microsoft technologies, including .NET, .NET Core, Azure, and related web technologies. Its legacy modernization work includes refactoring older applications into more modular structures, API-driven integration, cloud migration, and continued software maintenance. The company also works across frontend, backend, web application development, and cloud engineering, so refactoring projects can extend beyond isolated code cleanup into broader platform updates. SoftPro operates from Warsaw and supports software modernization alongside new custom development.

Brainhub structures legacy application modernization around several levels of intervention. Its published model distinguishes between rehosting, replatforming, refactoring, re-architecting, rebuilding, and replacing software. Refactoring is defined as restructuring internal code without changing system behavior, with goals such as better maintainability, testability, readability, and reduced technical debt. Brainhub also develops web, mobile, and desktop applications, which gives the company a broader engineering base for modernization projects that continue into feature development after the initial refactoring work.

21century.tech offers legacy refactoring as one of its defined project types. Its delivery model is AI-augmented, with senior engineers responsible for architecture while generated code goes through human review, testing, and the normal merge process. The studio also includes tests, documentation, CI/CD, and deployment in its delivery scope, which matters when refactoring needs to improve the development environment around the code rather than just rearrange individual modules. Third-party integration and full-stack feature work can be combined with legacy refactoring when the existing product is still actively evolving.

Rishabh Software provides application modernization for businesses moving away from older architectures and technology stacks. Refactoring is part of its service mix, including restructuring monolithic applications into microservices when that approach fits the system. The modernization process can also cover cloud enablement, application reengineering, UI and UX updates, technical assessment, and migration planning. Its emphasis on evaluating the existing technology environment before implementation makes it relevant for projects where the team first needs to determine how much of an application should be preserved and what requires deeper structural change.

Itexus is particularly relevant to refactoring projects in fintech and other financial software environments. Its current service material describes gradual modernization for tightly coupled legacy systems using integration layers, legacy service wrappers, anti-corruption layers, automated regression testing, and phased replacement patterns. A published WealthTech project shows the company taking over an inherited platform after a technical audit and carrying out stabilization, controlled refactoring, data-layer changes, and continued feature development. That combination supports projects where modernization must happen without stopping a production financial platform.