A curated 2026 directory of 18 platforms and agents that use AI to assess, refactor and transform legacy and mainframe codebases — including the nine vendors in Gartner’s August 2026 Magic Quadrant, from enterprise suites to general-purpose coding agents and deterministic, recipe-driven remediation at scale.
COBOL, RPG, PL/I, Assembler transformation
Multi-agent orchestration across codebases
Recipe-driven, reproducible code changes
Continuous analysis and remediation
Gartner’s Magic Quadrant for AI-Augmented Code Modernization Tools (published 3 August 2026) covers software that combines specialized AI agents, generative AI and deterministic analysis to speed up legacy transformation — from code and architecture analysis, documentation and dependency mapping to risk assessment, migration planning and refactoring. Gartner expects AI-augmented tools to carry out 90% of software modernization by 2029, up from under 10% today, and generative AI to cut human modernization labor costs by 60% compared with 2026 levels.
Enterprise platforms purpose-built for modernizing mission-critical mainframe, Windows and legacy applications at scale, each evaluated in the 2026 Gartner Magic Quadrant.
Agentic AI service for transforming Windows, mainframe, VMware and custom code, with dependency mapping, business-logic extraction and continuous tech-debt remediation. Assessment and the mainframe, Windows and VMware agents are free; custom transformation and continuous modernization are billed by agent minute.
Visit siteAI-augmented mainframe development platform unifying coding, testing and delivery. Code Insights exposes how complex mainframe applications fit together, and BMC AMI Assistant uses generative AI to explain COBOL, JCL, PL/I and Assembler.
Visit siteAI-enhanced platform for application assessment, business-rules extraction, documentation, dependency analysis and code migration across 20+ legacy languages including COBOL, PL/1 and Natural/ADABAS; it can also generate user stories and technical specifications.
Visit siteAI partner for the whole software lifecycle that combines deterministic analysis with AI reasoning to modernize complex legacy systems incrementally — business-logic extraction, refactoring and documentation, with packages for Java upgrades and mainframe/IBM i work.
Visit siteReplatforming-first mainframe modernization suite — Enterprise Analyzer, Developer, Visual COBOL and Enterprise Server — that preserves COBOL business logic while moving to modern IDEs. Rocket added OpenText’s Application Modernization and Connectivity business and an Assembler refactoring product in 2025.
Visit siteGeneral-purpose agentic coding tools that read, refactor, and modernize codebases directly from the terminal, IDE, or CLI — equally at home on legacy transformation and everyday development.
Anthropic's agentic coding tool that understands full codebases, makes multi-file edits, and turns issues into PRs from the terminal, IDE, GitHub, or Slack — with a dedicated code modernization solution.
Visit siteAI coding agent for ambitious software work: autonomous cloud agents run in parallel to understand legacy architectures, refactor code and carry out large-scale migrations, with developers kept in the loop across terminal, Slack and GitHub.
Visit siteAgentic software development platform built around a deep, continuously updated index of large codebases, useful for understanding and changing legacy systems at scale.
Visit siteCode search, intelligence and batch-change tooling that helps teams understand dependencies and apply changes across many repositories.
Visit siteRecipe-driven and plugin-based tools that apply precise, repeatable code transformations across single repositories or entire fleets.
Microsoft’s GitHub Copilot modernization, delivered as an open-source Copilot CLI plugin for Java and .NET — automated assessment, AI-driven code remediation, containerization planning and cloud deployment, using multi-agent orchestration for upgrades, CVE fixes and rearchitecture.
Visit siteDeterministic-first modernization platform that models code as a Lossless Semantic Tree and runs 10,000+ OpenRewrite recipes across Java, Spring Boot, C#, Kotlin, Python and JavaScript — one validated fix applied identically across one repository or a hundred thousand.
Visit siteThe open-source automated refactoring engine behind Moderne, with recipes for framework upgrades, security fixes and style changes across Java and other languages.
Visit siteVendors Gartner named as honorable mentions in the same research — relevant to AI-driven modernization, though outside the Magic Quadrant.
Autonomous software-development platform that reverse-engineers an enterprise codebase into a knowledge graph, then orchestrates thousands of agents to build and validate changes in parallel; supports air-gapped and private-cloud deployments.
Visit siteThe AI lab behind the Devin autonomous software engineer and the Windsurf IDE; Devin plans and carries out framework upgrades, database migrations and monolith restructuring, then checks results with unit tests and CI.
Visit siteAI-powered modernization platform for legacy systems in regulated industries, working in three phases — Explorer, Architecture and Coder — to map dependencies, propose migration strategies and generate code.
Visit siteGemini-powered tooling to assess, reverse-engineer and migrate mainframe workloads to cloud-native architectures, with business-rule extraction, a Dual Run tool that checks functional equivalence, and a connector for data and hybrid setups.
Visit siteMainframe modernization platform that treats the legacy system as a black box and re-creates its behavior from real data flows instead of translating code, running old and new components side by side through test-driven, continuous modernization.
Visit siteReverse-engineers legacy and modern codebases to recover business intent and generate documentation, architecture diagrams and machine-readable specifications for traceable, spec-driven development.
Visit siteThey are platforms and agents that use AI to assess, document, refactor and translate legacy code, such as COBOL, older Java or .NET, into modern languages and architectures, with developers reviewing the results.
It is Gartner's August 2026 evaluation of nine vendors in this market, with placements as Leaders, Visionaries and others. This page marks each evaluated vendor with its placement; Gartner does not endorse any vendor.
Recipe-driven tools such as OpenRewrite and Moderne apply precise, repeatable transformations that produce the same result every time. AI coding agents are more flexible and can reason about unfamiliar code, but need review and tests to confirm correctness.
Yes. Tools such as AWS Transform, IBM watsonx Code Assistant for Z, BMC AMI DevX, Rocket Enterprise Suite and EvolveWare analyze COBOL, extract business rules and generate target code. See the Mainframe Modernization page for more.
Treat it as a draft. Use automated tests, equivalence checks against the legacy system, code review and security scanning, and migrate in phases so each step can be validated before moving on.