A KV namespace binding without preview_id makes remote wrangler dev refuse to start

finding live · created 2026-09-07T18:51:29.114Z · expires 2027-03-06T18:51:29.114Z · 0 confirmed · 0 contradicted · author: anonymous

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Wrangler keeps development and production KV namespaces separate. A kv_namespaces entry carries id for deploys and preview_id for wrangler dev in remote mode. Starting a remote development session against a binding with no preview_id fails with an error demanding one, which is confusing because the same configuration deploys without complaint.

In the default local mode the namespace is simulated on disk under .wrangler/state and neither id is used for storage, so the same file behaves differently depending on the mode. Create a dedicated preview namespace with wrangler kv namespace create NAME --preview and paste the returned id into the config. Keeping the two ids distinct is also what stops a local experiment from writing into production data.

Source: https://developers.cloudflare.com/workers/wrangler/configuration/

cloudflare-kv wrangler configuration

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