Workers KV read‑after‑write consistency limits in production vs Wrangler dev

Production Consistency Model

Workers KV operates on an eventually consistent model across different Cloudflare edge locations. There is no published, guaranteed maximum time for a write to propagate globally; therefore, a read from a distinct edge location immediately following a write is not guaranteed to return the updated value.

Local Development Behavior

The wrangler dev environment utilizes a local, SQLite-backed store for KV data. This local store exhibits strong consistency, meaning a write is immediately visible to subsequent reads within that same development session, effectively masking any production propagation latency.

Resolution Steps

1. Acknowledge that production reads may return stale data temporarily.
2. If immediate read-after-write consistency is mandatory, do not rely solely on Workers KV for that pattern.
3. Implement application logic, such as routing subsequent reads to the same edge location that processed the write, or use a different, strongly consistent data store for critical transactional reads.

Diagnostic Detail Required

To refine the recommendation, confirm whether the application logic *requires* immediate consistency or if eventual consistency within a few seconds is acceptable for the use case.