When Event-Driven Systems Become the Source of Truth: Lessons from CDC, Kafka, and Replay-Safe Inventory Platforms
Abstract
This paper examines the point at which event streams stop being helpful integration plumbing and become operational truth for business-critical state. Using CDC, Kafka and replay-safe inventory platforms as the frame, it focuses on the failures that matter after the brokers are healthy: ambiguous replay intervals, duplicate business effects, stale projections, ordering mistakes, weak idempotency boundaries and recovery jobs that finish without proving correctness.
The central argument is that reliability in event-driven systems is not only a question of uptime or message delivery. Once downstream systems trust derived state, teams need explicit contracts for event identity, ordering, idempotency keys, dedupe horizons, CDC and outbox boundaries, replay controls, audit evidence and reconciliation. Readers leave with a practical way to judge whether retained events can repair business state without corrupting the systems that depend on it. Keeping events makes recovery possible. Boundaries and proof make recovery trustworthy.
- Published in
- Proceedings of the Raptors Conference, Vol. 1 (2026)
- Conference
- Raptors Conference 2026, 21 October 2026, online
- Accepted
- 2026-09-19
- DOI
- https://doi.org/10.68495/rc.2026.C028
- Presentation
- Slides (PDF)
- Licence
- © 2026Ishan Deepak Shah. Published under Creative Commons Attribution 4.0 International (CC BY 4.0).
- Publisher
- Hackathon Raptors, Community Interest Company 15557917, London, United Kingdom
- Permanent address
- https://proceedings.raptors.dev/shah-when-event-driven-systems
Open access. Every entry in the Proceedings is free to read, with no charge to authors and no charge to readers. Slides are served from this site, so they stay available at the paper's permanent address.
Cite this paper
Ishan Deepak Shah (2026). When Event-Driven Systems Become the Source of Truth: Lessons from CDC, Kafka, and Replay-Safe Inventory Platforms. Proceedings of the Raptors Conference, Vol. 1 (2026). Hackathon Raptors, London. https://doi.org/10.68495/rc.2026.C028
@inproceedings{raptors2026-c028,
title = {{When Event-Driven Systems Become the Source of Truth: Lessons from CDC, Kafka, and Replay-Safe Inventory Platforms}},
author = {Shah, Ishan Deepak},
booktitle = {Proceedings of the Raptors Conference},
volume = {1},
year = {2026},
publisher = {Hackathon Raptors},
address = {London, United Kingdom},
doi = {10.68495/rc.2026.C028},
url = {https://doi.org/10.68495/rc.2026.C028},
abstract = {This paper examines the point at which event streams stop being helpful integration plumbing and become operational truth for business-critical state. Using CDC, Kafka and replay-safe inventory platforms as the frame, it focuses on the failures that matter after the brokers are healthy: ambiguous replay intervals, duplicate business effects, stale projections, ordering mistakes, weak idempotency boundaries and recovery jobs that finish without proving correctness. The central argument is that reliability in event-driven systems is not only a question of uptime or message delivery. Once downstream systems trust derived state, teams need explicit contracts for event identity, ordering, idempotency keys, dedupe horizons, CDC and outbox boundaries, replay controls, audit evidence and reconciliation. Readers leave with a practical way to judge whether retained events can repair business state without corrupting the systems that depend on it. Keeping events makes recovery possible. Boundaries and proof make recovery trustworthy.}
}
TY - CONF TI - When Event-Driven Systems Become the Source of Truth: Lessons from CDC, Kafka, and Replay-Safe Inventory Platforms AU - Shah, Ishan Deepak T2 - Proceedings of the Raptors Conference VL - 1 PY - 2026 DA - 2026/09/19 PB - Hackathon Raptors CY - London, United Kingdom DO - 10.68495/rc.2026.C028 UR - https://doi.org/10.68495/rc.2026.C028 AB - This paper examines the point at which event streams stop being helpful integration plumbing and become operational truth for business-critical state. Using CDC, Kafka and replay-safe inventory platforms as the frame, it focuses on the failures that matter after the brokers are healthy: ambiguous replay intervals, duplicate business effects, stale projections, ordering mistakes, weak idempotency boundaries and recovery jobs that finish without proving correctness. The central argument is that reliability in event-driven systems is not only a question of uptime or message delivery. Once downstream systems trust derived state, teams need explicit contracts for event identity, ordering, idempotency keys, dedupe horizons, CDC and outbox boundaries, replay controls, audit evidence and reconciliation. Readers leave with a practical way to judge whether retained events can repair business state without corrupting the systems that depend on it. Keeping events makes recovery possible. Boundaries and proof make recovery trustworthy. LA - en ER -