Matthew Gumport · Cloudflare · 23 October 2026

A small video seek could fetch 128 MiB when it crossed two cache ranges. Cloudflare now reuses stored chunks, joins downloads already in progress and fetches missing chunks. Every piece must belong to the same file version. Small requests can still overfetch, but chunk size limits the waste.

Raul Junco · System Design Classroom · 22 October 2026

A refund doesn't erase the customer's experience of being charged. Raul's checkout example secures stock in an allocation that won't expire before committing payment. A payment timeout is trickier: you don't know whether it succeeded, so check what happened before deciding how to recover.

Callan Lamb and Brianna Heffernen · Datadog · 20 October 2026

A signed image can still contain an unreviewed change. Datadog's Turnstile checks signed evidence about its source, reviews and build against the target environment's rules. The team introduces checks in audit mode first. The rules themselves need protection too.

Meta engineering · 19 October 2026

Meta's data-column agent confused rules from different systems. Its replacement gives specialists only the knowledge they need, while a fixed workflow controls the steps and reliability checks. In this narrow production case, about two-thirds of changes land without significant human edits. Review remains part of the process.

AWS Architecture Blog · 14 October 2026

Moving traffic to another region doesn't restore an open WebSocket. The client must reconnect, authenticate again and recover its application state. AWS walks through that recovery and independent health checks. Asynchronous replication can still leave the latest writes behind.