Cloudflare has opened an invitation-only private beta of KV Instant, a new Workers KV mode built on Quicksilver, the configuration store it has used internally since 2020. In figures reported across more than 300 edge locations, KV Instant’s 99th-percentile read latency was 1.62 milliseconds, compared with 287 milliseconds for classic Workers KV. Cloudflare says Instant’s 95th-percentile read latency was measured in microseconds.
The more consequential difference for many applications may be how little—and how rarely—KV Instant can be written. Each namespace is limited to 10,000 key-value pairs and 1 MB of storage, with keys no longer than 300 bytes. Writes are capped at one per namespace per second; classic KV permits one per key per second. Applications that update several keys concurrently would therefore need to account for a namespace-wide write limit.
Pricing reinforces the read-heavy design. A write costs $0.10, versus $5 per million writes in classic KV. Storage costs $100 per MB per month, while reads cost 60% less than in classic KV. Multi-key reads are billed per key.
The mode uses the Workers KV API, but must be selected when a namespace is created and cannot be changed later. It does not support metadata—getWithMetadata returns null—and list returns all matching keys without pagination. Feature flags, routing tables and agent settings fit the small, frequently read configuration use case described in the report; frequently updated session or user data does not. Classic Workers KV remains Cloudflare’s recommended option for larger or frequently updated datasets.
Cloudflare has not announced a general-release date. It also cautions that its reported median and 95th-percentile replication figures for classic KV are upper bounds, not precise measurements, because it cannot measure that mode’s replication delay with subsecond precision.