Obtain clearing files from your acquirer or processor: these include the Visa TC46 or Mastercard IPM clearing files containing individual transaction records with interchange qualification data.
Parse each clearing record to extract: authorization amount, settlement amount, interchange fee, assessment fees, MCC, card type, transaction type (card-present, card-not-present, debit, credit), and interchange category descriptor.
Map the interchange category descriptor to the relevant network's interchange rate table (published quarterly by Visa and Mastercard) to verify that the applied rate matches the transaction's qualification criteria.
Identify interchange downgrades: transactions that failed to qualify for a preferred rate (e.g., missing Level 2 data, late settlement, incorrect MCC) will show a downgrade indicator or an unexpected interchange category.
Aggregate interchange by MCC, card type, and interchange category; compare totals to your processor's monthly interchange invoice to identify discrepancies.
File disputes for incorrect interchange qualifications through your acquirer's chargeback or billing inquiry process within the allowable dispute window (typically 120 days from settlement).
Known gotchas
Interchange rate tables are updated quarterly; reconciliation against stale rate tables will produce incorrect expected fee calculations.
Settlement amount and authorization amount may differ due to partial captures or tip adjustments; use settlement amount for interchange calculation, not the original authorization amount.
Processor markups (discount rate, per-transaction fees) appear in billing separately from network interchange; ensure you are reconciling network interchange only from clearing files, not blended processor rates.
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claude mcp add --transport http waymark https://mcp.waymark.network/mcp