BASE II Architecture
BASE II is Visa's legacy batch clearing system — the backbone of Visa transaction processing for decades. In the BASE II model, acquirers submit clearing files (TC05 records for sales, TC15 for credits, TC25 for chargebacks) to VisaNet on a defined cut-off schedule. VisaNet aggregates incoming records, applies the Edit Package validation rules, computes interchange for each transaction and produces outbound settlement files to issuers. Participants interact with BASE II via the Visa SMS (Single Message System) or DMS (Dual Message System) depending on whether authorisation and clearing are combined in a single message or separated.
VCE — Visa Clearing Exchange
VCE (Visa Clearing Exchange) is Visa's next-generation clearing infrastructure, replacing the batch-oriented BASE II model with a message-based, near-real-time clearing architecture. Key architectural differences:
- Message-based vs. batch-file: VCE processes individual clearing messages rather than batched fixed-width files, enabling faster exception detection and more granular transaction-level status tracking.
- ISO 20022 alignment: VCE introduces ISO 20022-compatible data structures alongside Visa's proprietary format — a significant change management undertaking for processors and host developers accustomed to BASE II field layouts.
- Enriched data: VCE supports enhanced data elements not present in BASE II — including Level 2/3 purchase data, extended merchant information and richer tokenisation metadata — enabling improved interchange qualification and analytics.
Edit Package Compliance
Every clearing record submitted to VisaNet is validated against the Edit Package — a comprehensive set of rules governing mandatory data elements, field format compliance, amount limits and logical consistency between related fields. Edit categories determine the outcome of a failing record:
- Reject edits: The clearing record is rejected outright. The acquirer must correct and resubmit within scheme-defined windows, or the transaction may become unrecoverable. Common reject triggers include missing mandatory DEs, invalid merchant category codes and amount field format errors.
- Accept-with-error (AWE): The record is accepted for clearing but flagged — often resulting in interchange downgrade rather than outright rejection. AWE conditions are a primary driver of interchange leakage for acquirers.
- Warning edits: Informational flags that do not affect clearing outcome but indicate data quality issues requiring remediation — important for maintaining scheme compliance scores.
T&E Clearing Requirements
Travel and Entertainment (T&E) transactions — airlines, hotels, car rental — carry specific clearing requirements under Visa's T&E programme rules. Estimated authorisations (common for hotel check-in and car rental) must be matched to final clearing amounts within defined variance tolerances. Incremental authorisations for hotel extended stays must follow specific DE sequencing. Failure to clear T&E transactions correctly is a frequent source of interchange downgrade and scheme compliance issues for acquirers serving hospitality merchants.
Visa Settlement Service (VSS)
VSS is the reporting and settlement delivery platform for Visa participants. VSS delivers net settlement reports (NSRs) detailing each participant's daily settlement position, interchange obligations and fee assessments. Issuers must reconcile their internally-computed net position against the VSS NSR — breaks require investigation and escalation to Visa Settlement Operations within same-day timelines. VSS also delivers position detail reports (PDRs) providing transaction-level clearing detail for reconciliation against internal transaction logs.