Give your COBOL a modern future.
We built Chrysalis, the transpiler that ports COBOL to Rust automatically — with byte-for-byte fidelity, memory safety, and zero platform lock-in.
The world runs on COBOL. The talent is retiring.
Mission-critical banking, insurance, payments, and government systems are written in COBOL — and the engineers who understand them are leaving faster than they can be replaced. Rewriting by hand is slow, costly, and dangerously error-prone.
The talent is leaving
Universities stopped teaching COBOL decades ago. Institutional knowledge is vanishing, and hiring gets harder every year.
The economics are breaking
Mainframes are expensive to license, run, and staff — and manual rewrites routinely blow budgets while subtly changing the business logic.
Port COBOL to Rust, mechanically.
Chrysalis reads your COBOL and emits a compiling Rust crate backed by a runtime that reproduces COBOL semantics exactly. Nothing "close enough" — the output runs byte-for-byte identical to the original.
Accurate
Fixed-point arithmetic, rounding, editing, and report output preserved exactly.
Reliable
Deterministic, no panics on COBOL-reachable paths, faithful transaction semantics.
Secure
Memory-safe Rust by construction — zero unsafe across the workspace.
Meet Chrysalis
Chrysalis — the COBOL-to-Rust transpiler
A suite written in Rust that mechanically ports COBOL source to idiomatic Rust, backed by a 30-crate runtime that reproduces COBOL semantics exactly — including the hard mainframe surface.
- CICS transactions, DB2 / embedded SQL, IMS/DL-I, Language Environment, IBM MQ
- VSAM-style files, the Report Writer, SORT/MERGE, and full fixed-point arithmetic
- Differential-tested byte-for-byte against GnuCOBOL; fuzzed; zero
unsafe
Five guarantees, jointly required
Accurate
Exact fixed-point arithmetic, rounding, and editing — byte-for-byte.
Reliable
Deterministic; no panics; faithful transaction/rollback.
Secure
Memory-safe by construction — zero unsafe code.
Fast
Scaled-integer fixed-point core — no string math.
Maintainable
Idiomatic, readable Rust a modern team can own.
The moat
A migration needs all five — most tools only promise one.
Modernize your COBOL estate without rewriting it.
Planning a migration — or know someone who is? Let's talk about what Chrysalis can do for your systems.
Talk to Se.Fier →