220 billion lines of COBOL.
5 governance tools.
Zero re-platforms.

Why the bridge, not another rewrite

COBOL modernization fails 40-70% of the time. Banks have spent decades migrating off, and the COBOL keeps running. The mainframe team retires; the system stays.

What changed in 2024-2026 isn't the mainframe — it's the governance perimeter. EU AI Act Article 12 wants audit logs across every decision-making system, AI or not. DORA Article 17 requires a Register of Information for all third-party ICT. NIS2 Article 23 wants 24-hour incident reporting on essential entities. None of that requires moving the COBOL — just signing what it does.

That's what COBOL Substrate is. Five MCP-native tools running outside the mainframe, reading copybooks + CICS + JCL, generating signed evidence packs that auditors verify by URL. The mainframe doesn't change. The compliance posture does.

5 integrated tools

By industry

FPT COBOL-Coder-14B → 73.95% compile success vs GPT-4o's 41.8%

Generic LLMs hallucinate COBOL constructs they've never seen at training time. The FPT-Software COBOL-Coder-14B model is fine-tuned on real COBOL estates and gives us 73.95% compiler-validated translation success vs GPT-4o's 41.8%. That's the difference between a transpilation that works and one that needs a human rewriter at every function boundary.

We integrate the model behind a compliance-aware wrapper: every translation generates a signed attestation chained into the existing MEOK audit-logger evidence pack, so modernization itself becomes auditor-defensible work — not just the output code.

Pricing

How to evaluate in 14 days

1. Days 1-3: Drop us 3-5 anonymised COBOL copybooks. Substrate runs Copybook Parser + PII detection + GDPR/PCI/HIPAA/SOX mapping.
2. Days 4-7: Point us at one CICS region + JCL job stream. We run CICS Bridge Assessment + JCL Batch Scanner — surface security + lineage gaps.
3. Days 8-11: Pick the top-3 risk programs from steps 1-2. COBOL-Coder-14B transpiles them to Python with compiler-validated output. Side-by-side diff for your team.
4. Days 12-14: Governance Crosswalk emits a signed evidence pack ready for your next DORA / NIS2 / EU AI Act audit. We hand off to your team or escalate to Defence tier.