56 providers tracked
Best Application Modernisation Partners 2026
Compare 56 partners delivering legacy application modernisation: re-hosting, re-platforming, microservices refactoring, mainframe migration, COBOL transformation, and cloud-native rebuilds across AWS, Azure, and Google Cloud. Listings show language depth, AI-assisted refactoring capability, and verified buyer ratings.
How to choose an application modernisation partner
Application modernisation in 2026 is defined by two structural shifts: hyperscaler-led migration programmes have absorbed most of the easy lift-and-shift work, and AI-assisted code understanding, refactoring, and test generation has materially changed the economics of refactor-grade modernisation. The right partner combines deep language and platform expertise with a credible toolchain for code analysis and AI-assisted transformation, not just consultant headcount.
Four procurement archetypes recur. Hyperscaler professional services (AWS ProServe, Google Cloud PS, Microsoft Industry Solutions) lead on programmes anchored to a single cloud and where migration credits materially offset partner cost. Engineering-led firms (EPAM, Thoughtworks, Globant, Endava, SoftServe) lead on refactor-heavy programmes where domain modelling, microservice extraction, and quality engineering dominate. Global SIs (Accenture, IBM Consulting, Kyndryl, TCS, Infosys, Cognizant) lead on mainframe and IBMi modernisation at scale and on programmes that bundle modernisation with infrastructure managed services. Automated migration specialists (Asysco, Modern Systems, TCS MasterCraft) lead on COBOL, RPG, and proprietary 4GL conversion where deterministic tooling outperforms hand-refactor.
For complementary research see integration platforms, API management, observability, and Kubernetes platforms. For adjacent services see cloud migration, DevOps and SRE, Kubernetes services, and custom software development.
Frequently Asked Questions
What does an application modernisation programme cost?
Re-host (lift-and-shift) of a typical mid-size .NET or Java workload runs $80k-$300k per application. Re-platform with managed runtime and database changes runs $250k-$1.2M per application. Full refactor to microservices with data model redesign typically runs $1.5-6M per application and 9-18 months. Mainframe and IBMi modernisation programmes routinely reach $20-150M depending on KLOC and conversion approach.
Refactor or re-platform?
Re-platform when the application is stable, well understood, and rarely changed, where the goal is operational cost reduction and managed runtime adoption. Refactor when product velocity, scalability, or team autonomy are the strategic goal. Strangler-fig refactoring around a re-platformed core is increasingly the dominant pattern, allowing incremental refactor of high-value modules while the legacy core continues to operate.
Does AI-assisted refactoring actually work?
For code understanding, test generation, and language conversion (COBOL to Java, VB.NET to C#, PL/SQL to PostgreSQL), AI assistance now delivers 30-60% productivity improvement on well-bounded modules with strong test coverage. For domain-driven decomposition into microservices, AI tooling improves discovery but does not replace senior architect judgment. Demand partner-provided benchmarks on previous engagements before believing headline claims.
How do we handle mainframe modernisation?
Mainframe programmes split into three viable patterns: automated code conversion (Asysco, Modern Systems, TCS MasterCraft) for cost-driven exits; emulation / rehosting (Micro Focus / OpenText Enterprise Server, AWS Mainframe Modernization, Azure mainframe migration) for risk-managed transition; and ground-up rewrite for systems where business logic is materially obsolete. Mixed-mode programmes that convert most of the estate and rewrite high-value workflows are now the dominant pattern.
What contract structure works for modernisation work?
Fixed-price by application or wave for re-host and re-platform with a small T&M envelope for exception handling. Time-and-materials with capped phase budgets for refactor. Outcome-based commercial models tied to retired servers, decommissioned licences, or cloud cost reduction are credible only when the partner controls both modernisation and run. Always require source IP, decomposition documentation, and full test artefacts at handover.