Legacy modernisation, verified

Modernise the core. See exactly what changed.

Montora moves COBOL to modern code one reviewed piece at a time, then replays it against how the original really behaved.

Migrate LOANPAY to Java and prove it still behaves.
LOANPAY·Replay
Example
  • ACC-10441standard1,201.50matched
  • ACC-10502late fee25.00matched
  • ACC-11873accrued88.12matched
  • ACC-20917accrued1,204.56matched
  • ACC-30114balance0.00matched
12,480 of 12,480 recorded runs matchedVerified

From code nobody understands to a change you can sign.

Four steps, each one reviewable. Nothing moves until a person says so.

Map how the overnight loan repayment batch works.
Reading LOANPAY and 14 related programs
Example
Steps

Reading source

Found the repayment calculation

LOANPAY.cbl · 3200-CALC-INTERESTDaily interest on the outstanding balance

Resolving copybooks

Found the account record layout

ACCTREC.cpy82 fields, 3 redefined

Extracting business rules

Recovered 23 rules

Rule 07 · Late fee capped at £25Set in 2019, applies after 5 days late

Tracing the batch

Mapped the nightly job

JCL LNPAYD014 steps, runs at 02:10

The model that writes the code never marks its own work.

Migration and verification run on separate lineages, so a passing replay means something to your risk team and to your auditor.

Not a translator.A migration you can defend.

01

The rules come with it.

Every fee, cap and eligibility check is recovered, carried across and traced back to where it was set.

Rule 07 · Late fee capped at £25
02

People decide.

Work stops at every piece for someone on your team to approve, edit or reject. Nothing merges on trust.

Request changesApprove
03

You see what didn't match.

Replay shows each difference with the input that caused it, so a pass is evidence rather than a claim.

ACC-20917accrued1,204.57 ≠ 1,204.56

Built for systems that can't go down.

Sandboxed

Untrusted code runs in isolation, with no network access.

Independent

The data that proves the code is never used to write it.

Signed

Every result is signed and can be reproduced by anyone.

Yours

We process your code for you, never for anything else, and delete it when we're done.

How we handle security

Questions, answered.

Still unsure? Talk to us.

Legacy systems like COBOL mainframes, moved into whatever modern language your team chooses: TypeScript, Java, Python, Go, Rust, or C#. It works one chunk at a time, so you are never staring down a whole estate at once.

See Montora on your own code.

We're working with a small number of design partners. Tell us what you're modernising.