Legacy Mainframe Migration - Tools and Services

Migrate off the mainframe by converting COBOL to modern languages. A desktop transpilation tool for self-service migration, plus professional services for assessment, conversion, data migration, and validation of enterprise codebases.

6 Target Languages Mainframe Exit Cloud-Ready Output Migration Services

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If your organization is looking at legacy mainframe migration, the biggest question is what happens to the COBOL. Replatforming (running COBOL on Linux) buys time but keeps the talent problem. Full modernization converts your COBOL programs to C++, Java, Python, Rust, Go, or C# so modern developers can own the code. Our approach gives you both a desktop transpilation tool for hands-on conversion and professional migration services for organizations that need end-to-end project delivery, from initial assessment through parallel validation.

Why Organizations Are Leaving the Mainframe

Mainframe Costs Are Unsustainable

MIPS-based pricing, software licensing fees, and specialized hardware costs run into millions annually. The same workloads on modern infrastructure (cloud, commodity servers, or containers) cost a fraction of the mainframe bill.

The Talent Pipeline Is Empty

COBOL developers are retiring faster than they can be replaced. Recruiting and retaining mainframe talent has become the single biggest risk factor for organizations still running legacy systems.

Vendor Lock-In Limits Options

Mainframe platforms restrict where and how you deploy. Cloud migration, microservices, containerization, and CI/CD pipelines are effectively impossible while your core business logic is locked in COBOL on a proprietary platform.

A Practical Approach to Mainframe Migration

Six Target Languages

Convert COBOL to C++ 17, Python 3, Rust, Go, Java 17, or C# 12. Choose the right language for your team's skills, target platform, and performance requirements.

Real Compiler, Not a Translator

The tool builds a full AST with semantic analysis. Generated code is idiomatic to the target language, not a line-by-line transliteration that preserves all the readability problems of the original.

Assessment Before Commitment

Run your COBOL through the tool before committing to a migration project. The Migration Report gives you an instant view of complexity, dependencies, and areas that need manual attention.

Cloud-Ready Output

Converted code runs on any platform: AWS, Azure, GCP, on-premises Linux, or containers. No mainframe runtime dependencies in the generated output.

Self-Service or Full-Service

Use the desktop tool for in-house migration or engage professional services for end-to-end project delivery. Start self-service and escalate to full-service as needed.

Validation Built In

Migration Reports flag everything that needs attention. For full-service engagements, parallel running ensures the new system produces identical results to the mainframe before cutover.

The Mainframe Migration Process

Discovery and Assessment

Inventory your COBOL programs, JCL, copybooks, and data dependencies. The migration tool's diagnostics provide an instant complexity baseline for any program. For full-service, We deliver a complete assessment report with risk analysis.

Architecture and Target Selection

Choose the target language and platform based on your team's skills, performance needs, and deployment model. Design the data migration strategy for VSAM, flat files, and DB2.

Automated Conversion

Run COBOL programs through the transpiler. The compiler pipeline handles lexing, parsing, semantic analysis, and code generation. Batch processing is available for large codebases.

Manual Refinement and Data Layer

Address flagged items: EXEC SQL to modern database access, EXEC CICS to API/service layer, file I/O to modern formats. Implement the data migration from mainframe formats.

Testing, Validation, and Cutover

Compare output from the new system against mainframe production results. Run both systems in parallel until validation is complete. Plan and execute the mainframe decommission.

What You Get

Converted Source Code

Idiomatic, readable code in your chosen target language with clear module structure and proper data type mapping.

Migration Reports

Per-program diagnostics covering complexity, dependencies, flagged constructs, and manual review items.

Data Migration Plan

Strategy for converting VSAM files, flat files, and DB2 data to modern storage formats (PostgreSQL, cloud databases, structured files).

Architecture Documentation

Target system architecture, module structure, deployment model, and integration points with existing systems.

Parallel Validation

Testing approach and, for full-service engagements, active parallel running until the new system is proven equivalent.

Phased Migration Roadmap

Sequenced migration plan with milestones, risk mitigation steps, and rollback procedures for each phase.

Frequently Asked Questions About Legacy Mainframe Migration

What is the difference between mainframe replatforming and mainframe migration?

Replatforming moves COBOL applications to a new runtime environment (running COBOL on Linux, in containers, or in the cloud) without changing the language. Migration converts the COBOL source code itself to a modern language like C++, Java, or Python. Replatforming is faster and lower-risk but leaves you with COBOL code and the same developer shortage problem. Migration is a deeper investment that eliminates the mainframe dependency entirely. Learn more about the full approach on our COBOL modernization page.

How much does mainframe migration typically cost?

Costs vary widely based on codebase size, complexity, and target architecture. The Easy COBOL Migrator desktop tool is available for in-house migration. For full-service migration, pricing is based on an initial assessment of your codebase. In both cases, the investment is measured against ongoing mainframe costs, which typically run into millions per year for mid-to-large organizations.

Can I migrate from the mainframe in phases?

Yes, and phased migration is the recommended approach. Start with lower-risk, self-contained programs. Validate the converted code against mainframe output. Gradually migrate more modules while running the mainframe and the new system in parallel. This minimizes risk and gives your team time to build confidence with the new platform.

What about JCL and batch scheduling?

JCL (Job Control Language) handles batch scheduling, file allocation, and job sequencing on the mainframe. In the modern environment, these functions are replaced by shell scripts, cron jobs, cloud-native schedulers (AWS Step Functions, Azure Logic Apps), or dedicated orchestration tools (Apache Airflow, Control-M). The migration tool focuses on COBOL program conversion; JCL replacement is addressed as part of the target architecture design in full-service engagements.

Will my converted code run in the cloud?

Yes. The converted code has no mainframe runtime dependencies. C++, Java, Python, Rust, Go, and C# all run natively on AWS, Azure, GCP, and any Linux or Windows server. You can deploy as containers, serverless functions, or traditional applications depending on your infrastructure strategy. See the specific conversion pages for Java, Python, and C++ output details.

How do I handle VSAM files and DB2 data during migration?

VSAM files (KSDS, ESDS, RRDS) are typically migrated to relational databases (PostgreSQL, MySQL) or structured file formats (CSV, JSON, Parquet) depending on access patterns. DB2 data can often be migrated directly to PostgreSQL or another relational database with schema mapping. The migration tool flags EXEC SQL blocks so you know which programs need data access layer updates. Full-service engagements include data migration strategy and execution.

Planning a Mainframe Exit?

We provide full-service mainframe migration including COBOL code assessment, target architecture design, automated conversion, data migration planning, output parity testing, and parallel running support.

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