Autonomous mainframe & legacy-code modernization
Modernize your mainframe and legacy code —and prove, line by line, it still works.
Modernization stalls for five reasons. Agentyx removes every one — starting with the one that scares you most: the risk of breaking a system that runs your business. We run your original programs and the new code side by side and prove they behave identically before anything ships.
And by default, your source code never leaves your control — you redact it on your own machines and we modernize code we cannot read. How the code-privacy standard works →
Built by engineers and architects with deep, hands-on experience in legacy modernization — COBOL, mainframe and enterprise systems.
Why modernization stalls
Five reasons it stalls. Five answers.
Most teams running legacy systems already know the risk of not modernizing. What freezes them isn’t one problem — it’s five. Here’s each, and exactly how Agentyx dissolves it.
“If it isn’t broken, don’t touch it.”
We run your original code and the new system in parallel on the same inputs, and prove they behave identically — program by program. The same engine confirms your documentation against real runs before you start, so there's no big-bang to fear.
See equivalence testing →“It costs millions and takes years.”
An autonomous agent builds the modernization tooling once, then runs it across the whole estate deterministically. You pay per program, not per year — incrementally, with no multi-year big-bang to overrun.
See the math →“Nobody knows what the code does anymore.”
Agentyx generates grounded specifications and business rules where every statement traces back to the exact source line — documentation you can verify, not an AI’s guess. The lowest-risk place to start.
How we remove it →“We can’t even hire COBOL people anymore.”
You don’t need COBOL — or other legacy-language — experts. The platform understands the legacy code; your team owns clean, idiomatic Spring Boot — a skill you can actually hire for. Retiring expertise is captured in the documentation on the way out.
How we remove it →“Our source code can’t leave the building.”
Run Agentyx inside your own cloud — or fully sealed on-prem — so your source never reaches Anthropic or us. Up to a blind-vendor mode where we receive nothing but anonymized signals.
See deployment options →Blocker 01 · Risk
We run the old and new programs side by side — and compare every output.
Modernized code that merely compiles isn't enough. Agentyx runs your original program and the converted one in parallel on the same inputs, then compares their outputs value-for-value. If anything diverges — a wrong total, a different rounding, an off-by-one — the build fails before it ever ships.
- → Same inputs, both programs — outputs compared automatically.
- → Every matched scenario becomes a permanent regression test.
- →Proven equivalent to the original — and we show you exactly what was verified, and what wasn't.
The same engine, two ways:
Behavioral confirmation — before you modernize, we run your original alone and confirm each documented rule against its real output. No new system needed.
Parallel run — during modernization, we run the original and the converted side by side and prove they match, value-for-value.
See it on real code
A real modernization, open for inspection
Not a mockup — an actual mainframe application run through Agentyx, with the original source, the modernized output, and the build report all there to inspect.
AWS CardDemo — mainframe credit-card application
A real COBOL / CICS mainframe credit-card application, modernized by Agentyx. Compare the baseline against the modernized output, and inspect the build report from the first phase.
Blocker 02 · Cost & time
About 50× per program — and it holds across the whole estate.
The speed comes from building the tool once and reusing it deterministically. Here's the honest decomposition.
Hand-translating agentically — read it, rewrite it, write the tests, fix what breaks — an agent gets through about 12 programs in 20 minutes (~1.7 min each). Agentyx orchestrates a deterministic tool that does the same in about 2 seconds per program.
The tool is built once, then reused. Every additional program is modernized and verified deterministically in ~2 seconds of compute — not minutes of agent reasoning — so the advantage holds across thousands of programs, reproducibly.
The bigger the codebase, the bigger the win — and the conversion, the tests, and the documents all fall out of the same deterministic run. Integration and cutover remain real work, but they become small, de-risked steps instead of one multi-year leap.
What we modernize
Any legacy language — even binaries with the source long gone.
Agentyx modernizes legacy code in any language. And optionally, it goes a step further: when the source is gone entirely, it works from the compiled executable itself. A surprising amount of business-critical software survives only as a binary — the source long gone, the vendor vanished, the original authors retired. Even when old source exists, hidden toolchain and build-system dependencies often make it impossible to recompile cleanly. So Agentyx can recover what the binary does — the one authoritative artifact — re-emit modern software for today's operating systems and hardware, and prove it matches the original.
- → Legacy code in any language — COBOL, mainframe, assembler and older application stacks
- → CICS / BMS screens, batch and online programs
- → Optional — compiled executables when the source is lost: Windows (PE), macOS (Mach-O), Linux (ELF)
- →Even stripped binaries with no source at all — up to 250 MB
- → Modern native binaries — x86-64 and ARM64, across Windows, macOS and Linux
- → Or clean, maintainable modern source you can own
- →A test suite proving it matches the original's real behavior
- → Line-by-line traceability for audit
→ Move an x86 app to Apple Silicon / ARMwhen there's no source to recompile.
→ Get off an end-of-life OS — Windows 10 reached end-of-support on Oct 14, 2025.
→ Revive a tool whose vendor is gone or whose authors have left.
→ Port 32-bit to 64-bit, or recompile for hardware that no longer exists.
We modernize what recovers cleanly. Heavily packed, obfuscated or self-modifying binaries are harder — and, as always, we report exactly what's covered and prove equivalence on what we convert.
Blockers 04 & 05 · Skills & privacy
Deployment, security and support on your terms
Built for regulated estates that need control over where the work runs and who touches the code.
Powered exclusively by Claude Code
No model-shopping, no swapping providers mid-project. The entire pipeline runs on Anthropic's Claude Code — one model to vet, one supply chain to audit, and consistent behavior on every run. Run it in your own cloud via Bedrock or Vertex AI, and your code never reaches Anthropic or Agentyx.
On-prem deployment
Run Agentyx entirely inside your own infrastructure — nothing has to leave your network.
Dedicated server & agent execution
Every project runs on isolated, dedicated compute with its own agent runtime — never shared tenancy.
SSO login
Single sign-on with your identity provider (SAML / OIDC), mapped to your own roles.
Code privacy
Agents don't read your source line-by-line — the deterministic layer processes it. Optionally run Claude in your own cloud via Amazon Bedrock or Google Vertex AI, so code never reaches Anthropic or Agentyx servers.
Custom framework & coding style
Output matches your target frameworks, architecture and coding standards — configured per client.
Optional data migration
Migrate your data alongside the code, or modernize the code alone — your call.
Dedicated account manager
A named point of contact who knows your estate and your goals.
Premium end-to-end support
White-glove support across discovery, modernization, verification and rollout.
The incremental approach
Turn a multi-year, fixed-bid gamble into a pay-per-program program.
Big-bang modernizations fail for three reasons: they run for years while requirements drift, nobody can prove the new system is correct, and budgets overrun. Agentyx inverts all three.
Incremental
Modernize and prove one program at a time. No multi-year big-bang where the goalposts move before you finish.
Proven at each step
Behavioral equivalence is verified before each program ships — so cutover stops being a leap of faith.
Predictable
Deterministic, repeatable output means per-program pricing your CFO can budget — not open-ended time-and-materials.
We collapse and de-risk the translate–verify–document work. Cutover, data migration, integration and change management stay a partnership — we make them incremental and provable, not a single high-stakes leap.
Services & pricing
Start by understanding your estate, modernize it program by program, and add the enterprise services you need. Prove it for free first.
- →Modernized code + tests + traceability
- →Behavioral-equivalence report
- →See it on your own program — free
- →Grounded specs, business rules & runbooks
- →Every statement traced to the source line
- →Behavioral confirmation — each rule checked against real runs of your program (on the scenarios we can run)
- →Those scenarios become your parallel-run test corpus when you modernize
- →Standalone — source can stay on your premises
- →A fast, running prototype of your hottest paths
- →Load-tested at your real production volume
- →Throughput, p99 latency & batch-window report
- →Go / no-go + a bottleneck map
- →Modern code + tests + line-by-line traceability
- →Behavioral equivalence proven at each step
- →Incremental & deterministic — pay per program
- →Independent parallel-run testing — old vs new, whoever built it
- →We localize exactly where the new system diverges from the original
- →Honest, auditable coverage your risk team can sign off on
- →Rescue a failing cutover before it ships
Modernization is billed per line of code generated in the deliverable (tests included). Documentation, data migration, integration, on-prem, SSO and privacy deployments are scoped per engagement — talk to us.
Frequently asked questions
Agentyx is an autonomous software-modernization platform for large enterprise legacy estates. It turns COBOL mainframes, other legacy code, and even compiled executables whose source has been lost, into modern, maintainable software, and proves the result behaves identically to the original. An autonomous agent builds a deterministic Analyzer → Model → Builder pipeline tailored to your codebase, then runs it across the estate to generate modern code, a regression-proof test suite, and grounded documentation.
Built by experts
Built by professionals who do legacy modernization for a living
Agentyx is built by engineers and architects with deep, hands-on experience delivering real legacy-modernization projects — COBOL, CICS, mainframe and large enterprise systems. The hard-won know-how from those engagements is encoded into the platform, so every conversion reflects how experts actually do this work — not a generic code tool guessing its way through your estate.
How it works
Document, build, run — and prove every step
- 01
Document
It starts with our code-privacy standard: you redact your source on your own machines, so what the agent reads is structure — neutral tokens, not your names, values or comments. From that it produces grounded, line-traceable specs and rules, which you restore locally with keys only you hold — so you understand the system before you change it, without it ever leaving your control.
- 02
Build the engine
It generates a deterministic engine tailored to your codebase and design standards — an Analyzer that reads your code, a Model of its behavior, and a Builder that produces the modern output — plus matching test and document generators.
- 03
Run at scale
The toolchain executes across the estate, deterministically and in parallel — thousands of programs from one reusable build.
- 04
Prove everything
Each output is verified against your original program's real behavior, captured as a regression-proof test suite, and traced line by line.
🔒 Every step runs under our code-privacy standard — by default.
Before anything is uploaded, you redact your source on your own machines with our open-source tool: names, values and comments become neutral tokens, and the keys that restore them never leave you. Agentyx documents, builds and proves on code it cannot read — you restore the finished result locally. How it works →
See it on your own code
Start with a free evaluation. Bring one program or a whole estate — watch the agent modernize it, generate the tests, and prove it matches the original.