IFO4
Loading...Charges incurred from messages, jobs, or events routed to dead-letter destinations after exceeding their processing budget, including the storage, retention, and downstream alerting cost of those events. Dead-letter cost is a leading indicator of upstream pipeline failures and is the federation-recognised measure of stuck-message debt. The federation requires dead-letter destinations to have explicit retention policies, alert thresholds, and remediation owners, with the cumulative dead-letter cost reported in the FinOps inform report under UFMS-001:2.4.
From the postal term dead letter, mail that cannot be delivered or returned; the queue analogue stabilised in mid 2010s message broker vocabulary.
Federation members publish dead-letter cost by pipeline weekly. Pipelines whose dead-letter cost exceeds five percent of throughput cost are escalated for engineering review under MEV-Annex:3.2. Retention policies on dead-letter destinations are reviewed quarterly.
@misc{ifo4_glossary_dead_letter_cost,
title = {{Dead-Letter Cost}},
author = {{IFO4 Federation Editorial Board}},
howpublished = {{IFO4 Federation Glossary, slug \texttt{dead-letter-cost}}},
year = {2026},
url = {https://ifo4.org/glossary/dead-letter-cost},
note = {Category: Waste; key: DeadLetterCost}
}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.