Create a preview namespace for local dev
kv
// what it does
Creates a separate namespace for `wrangler dev --remote` to use, keeping test data out of production KV. Paste the returned id as `preview_id` next to the production `id` in the same `kv_namespaces` entry in your config.
// shell
$ wrangler kv namespace create SESSIONS --preview// gotcha
`wrangler dev --remote` reads `preview_id` while `wrangler deploy` uses `id`. With no `preview_id`, remote dev warns and falls back to the production `id` — so dev can silently read and write prod.