Turkcell documented real-time rating and mediation logic ahead of a 5G-era core platform refresh.

Turkcell, Turkey's largest mobile operator, serves more than 40 million subscribers across prepaid, postpaid and digital-services lines of business. Real-time charging, batch settlement and mediation between network elements and billing all run at scale on a COBOL-anchored core, and the engineers who designed those rules were the only ones who fully understood the edge cases under heavy load.

COBOLpro documented the rating and mediation logic in advance of a 5G-era core platform refresh. Prepaid and postpaid rating engines, cross-product bundles, batch-settlement chains, and mediation rules were captured from source, then validated in review sessions with the original engineers — including the corner cases that only show up at multi-million-event-per-second loads.

The reviewed package gave Turkcell's migration team a deterministic reference against which to design the new converged charging stack: which rules transfer cleanly, which require rewrites, and which depend on legacy assumptions that no longer hold. The same artefact is now the on-boarding reference for engineers joining the rating estate during the migration.