What's new · vFunction 5.0

vFunction 5.0: bring your largest applications into the AI era.

AI-driven development needs a system model, specifications, and tests. Your largest Java and .NET applications never had them. vFunction 5.0 generates them from the running application, and moves the database with it, all delivered with our forward-deployed engineers working alongside your team.

What 5.0 means

The applications you couldn't touch become the ones you can build on.

5.0 generates evidence-backed specifications and integration tests from the running application, migrates the database to PostgreSQL, and delivers all of it to Kiro, Claude Code, and other AI coding tools.

Modernize it with AI

AI coding tools rewrite one domain at a time against real specifications, with tests proving each change.

Specifications ↓

Develop it with AI

Specifications, tests, and a system model, connected to your tools over MCP. Every change is a specified, tested change.

MCP server and skills ↓

Build on it again

Specified and tested, your most critical application stops being the one the roadmap routes around.

Let's Talk ↓
Specifications

A specification for each domain, from production behavior

Built from the runtime flows vFunction observed. Every element backed by evidence, not inferred.

  • Flagged architectural issues factored in, so generated code doesn’t repeat them
  • One specification per domain, one domain at a time
Integration tests

Integration tests from production traffic

Generated from observed traffic, not static code. An application with no tests gets substantial coverage without anyone writing them.

  • A safety net from the first change
  • Proof the new code behaves like the old
MCP server and skills

Delivered to Kiro, Claude Code, and Other AI Coding Tools

The tools write the code: Kiro, Claude Code, AWS Transform, and others. vFunction hands them the specification, the tests, and the guardrails over MCP.

  • Code generation skill — from spec to code, one domain at a time, via API, CLI, or the Modernization tab
  • Claude Code and Kiro from the CLI — no VS Code extension needed
  • AWS Transform for Java — alongside .NET
  • Any other AI coding tool — through the MCP server
Database

Move the database with the application

SQL Server, Oracle, or DB2 to PostgreSQL, as a step in the same workflow.

  • Schema, SQL dialect, drivers, and ORM (Hibernate or EF Core) converted
  • Table usage shown before migration; unexercised tables reported after
  • Stored procedures converted to code
Let's talk

Tell us about the application.

Java or .NET, roughly how large, where it runs. We come back with what 5.0 would produce for it and how it’s priced.

What happens next

  1. A person reads it — not a scheduler.
  2. You hear back with pricing and the funding path.
  3. If it fits, a conversation with an engineer.
Also in 5.0

Also in this release

Plus Java agent performance work, C# record support, and better iBATIS/MyBatis analysis. .NET Core 3 is no longer tested.

Modernization tab

One place to run the whole workflow — including a single workflow for the entire application.

.NET 10

.NET 10 as the default target. Compile-time and runtime version reporting. C# client library generation from OpenAPI.

Operations

Logs to Datadog, OpenSearch, Grafana Loki, and Coralogix. Tuned Docker MySQL. Kafka OpenTelemetry attributes.

Questions about 5.0

Is vFunction 5.0 available now?

Yes, to vFunction customers, in your own environment. Also on the AWS, Azure, and Google Cloud marketplaces.

Does vFunction write the code?

No. Kiro, Claude Code, AWS Transform, or your tool of choice does. vFunction gives it the specification, the tests, and the context.

Which AI coding tools does 5.0 work with?

Kiro and Claude Code (CLI or VS Code), AWS Transform for Java and .NET, and anything that connects over MCP.

Which databases can be migrated?

SQL Server, Oracle, and DB2 to PostgreSQL: schema, dialect, ORM, stored procedures. Moving the data is done with your database tooling.

Which applications is 5.0 for?

Java or .NET applications past roughly 500,000 lines of code or 1,000 classes. Below that, an AI coding tool alone is usually enough.

How does a modernization with 5.0 run?

vFunction's engineers with your team, in your environment, one domain at a time, until your team runs it alone. See How an engagement works on the pricing page.

How is vFunction priced?

Per application, no per-user fees, often funded by AWS for applications on AWS. See Pricing.

Where to go next

Keep going

The platform →
Use cases →
Power AI-Driven Development for Existing Applications →
Full-Stack Windows Modernization →
How an engagement works →
Customer stories →

Tell us about the application

Java or .NET, roughly how large, where it runs. We come back with what 5.0 would produce and how it's priced.