Overwrite

How it works

Without versioning the old bytes are gone. With versioning they remain under a version id. A transfer that uses the partner's filename will overwrite yesterday. Generated keys avoid that. A confirmed overwrite is sometimes the contract.

A nightly file always named inventory.csv overwrites. Tuesday's bad run replaces Monday until they restore a version. A key named inventory-2026-10-06.csv would have kept both.

How it differs

Overwrite is not a duplicate. One key, new bytes. A duplicate is two keys.

A client cached the old URL and mixes bytes if the ETag is ignored.

Send validators.

On the ticket

• The practical close is a log line: time, actor, byte count, result.
• Without that line the transfer is a story.
• With it, the next person can see whether this door did what the ticket claimed.
• If the path is shared, say so in the partner profile so a later change does not silently pick a different limit, key, or region.
• On a real ticket, write down the door, the byte count, and the clock.
• For overwrite, that means naming the host or bucket, the expected size, and the time the other side must have a complete file.
• A progress bar is not that record.
• A 200 response that arrives before the complete call is not that record.
• If a retry is allowed, say how many and whether it resumes.
• If a person must approve the send, name the person.
• Partners who receive overwrite files should match on hash or size before they import.
• A same-length corrupt file passes a size check and fails a hash.
• Keep the published hash off the only channel an attacker can edit, or treat it as a corruption check rather than a substitution check.
• When the path changes, new key, new region, new cap, update the profile the same day so the next run does not use a stale limit.