Cost Per Transaction

I. Formal Definition

The variable cost attributable to a single transaction or business event, computed as the relevant cost basis divided by transaction count over the period. Cost per transaction is the federation-preferred denominator for high-volume request-driven services and for marketplace, payments, and event-processing businesses. The federation requires the transaction definition to be unambiguous, with batched, retried, and replayed events handled under a documented rule per UFMS-001:2.4(h). Cost per transaction trend reporting is required across at least four periods to support the IFO4 Score.

II. Etymology

A direct extension of industrial cost accounting per unit, applied to digital transactions; the cloud sense stabilised with the rise of microservice billing in the mid 2010s.

III. Federation Usage

Federation members publish cost per transaction with rules for batched and retried events. Trend reporting across four quarters is mandatory for accreditation evidence under MEV-Annex:3.2. Anomalous step changes are footnoted with engineering analysis.

IV. Related Terms

• cost-per-unit
• cost-per-customer
• unit-economics
• cost-attribution

V. Authoritative Citations

• UFMS-001:2.4UFMS Article II - Transaction Costing
• MEV-Annex:3.2MEV Annex III - Transaction Cost Reporting

VI. Citation in BibTeX

@misc{ifo4_glossary_cost_per_transaction,
  title        = {{Cost Per Transaction}},
  author       = {{IFO4 Federation Editorial Board}},
  howpublished = {{IFO4 Federation Glossary, slug \texttt{cost-per-transaction}}},
  year         = {2026},
  url          = {https://ifo4.org/glossary/cost-per-transaction},
  note         = {Category: FinOps; key: CostPerTransaction}
}

VII. Challenge This Definition

Federation members and accredited practitioners may challenge any entry under TGS-002:1.7. Filed challenges are routed to the editorial board, triaged into the revision register, and resolved in writing on the public docket. The slug remains stable through any revision.