SAP S/4HANA · custom-code transition
The custom Z-code is the riskiest part of your S/4HANA move. caern turns it into graded evidence.
caern reads your live SAP system, measures the custom code that fights the transition — what breaks, what defies Clean Core, what is dead weight — and turns it into a graded, prioritised, evidence-backed plan, explored and reported in a cockpit that runs inside SAP. Not a guess.
The wall
Every S/4HANA programme hits the same wall: the custom code.
It is usually the biggest unknown in the whole transition — and unknowns are where timelines and budgets slip.
How much exists?
What breaks on S/4HANA?
What fights Clean Core?
What is dead weight — and what will it cost?
caern answers all four, from the system itself.
The toolkit
Six lenses on one estate.
Each wedge reads one signal and emits one normalised result. Together they grade the whole custom-code estate — and every surface shows the same numbers.
S/4HANA readiness
Real ATC plus the Simplification DB — exactly what your Z-code touches that changes on the target.
Clean-Core posture
Direct SAP-table access vs. released APIs — scored 0–100 with a letter grade and a CI gate.
As-is footprint
Per object, the SAP tables and function modules it actually touches — the raw material for an as-is map.
Dead code
Neither executed (call monitor) nor referenced (where-used) — candidates you retire, not migrate.
Fiori successors
Each custom transaction mapped to its Fiori-app successor, so the UI move is planned, not discovered.
Grade + person-days
The whole estate graded A–F against a benchmark, with an honest migration-effort band.
The application
An analysis & reporting cockpit — inside SAP.
caern’s main surface is a single-page cockpit that runs natively inside your SAP system, served from its ICM — browse and select packages, run the analysers as a pipeline, and read the results without leaving the page. Prefer nothing installed? A thin-touch CLI runs the same analysis from outside over ADT — and adds CI gates and client-ready decks. Either way, caern is read-only: it analyses your custom code, never changes it.
Portfolio KPIs and worst offenders · a searchable package browser with checkbox multi-select · a packages × tools matrix · the estate grade and effort estimate · chart-led reports with PDF / PNG / CSV export · run history with compare-to-previous. All read-only, all in the browser — and no selection→result screen jumps.
Read-only, never writes
Reads the estate — inventory, source, ATC, call-monitor, where-used — and never modifies your custom code.
One model, one number
A single transparent model scores the estate A–F against a Clean-Core benchmark — recalibratable, never re-invented per view.
Cockpit or deck
Explore and export in the in-system cockpit, or generate a client-ready deck from the CLI companion. One contract behind both.
One contract behind everything: caern.export/v0
· wedge → grade → report
The honest part
A number with an uncertainty band — not a sales quote.
caern estimates only the custom-code work it actually found — remediation plus a test, documentation and cutover overhead — not a full S/4 programme, and not a greenfield rebuild. Dead code is flagged to retire, not to migrate. The grade and the days come from one model you can inspect and recalibrate. Where the evidence stops, caern says so.
Get started
See the source. Start a conversation.
caern is source-available for evaluation. Read the code, or reach out about your transition.