Cloudflare launches Workers KV Instant, powered by Quicksilver

Cloudflare introduced Workers KV Instant on October 1, a new mode for Workers KV that pushes changes across its global network for instant availability and eliminates cold read penalties. The mode runs on Quicksilver, the internal key-value store Cloudflare has long used but never offered to customers before.

Workers KV has been one of the most popular services on Cloudflare's Developer Platform since it launched during Birthday Week in 2018, serving data that is written occasionally but read frequently, such as static assets and user configuration. Quicksilver, introduced publicly in 2020, was designed for very fast global replication and low-latency access. Cloudflare says nearly every request to its network looks up at least one key in it.

100x faster reads, 20x faster writes

Reads in KV Instant resolve more than 100 times faster than in classic mode: latencies stay under 2 milliseconds even at p99 across all locations (1.62 ms), while p95 times are measured in microseconds. Classic mode's p99 read latency across all locations is 287 milliseconds.

Writes reach the edge more than 20 times faster: 99% of writes replicate in around 250 milliseconds, with a median of 107 ms, p95 of 181 ms and p99 of 256 ms. Classic mode's replication takes several seconds, with a p99 of 4.38 seconds. Cloudflare replicates the data to more than 300 edge locations.

Same API, three differences

KV Instant keeps the familiar Workers KV API, including get(), put(), list() and delete(). There are three differences: teams must specify instant mode when creating a namespace, metadata is not supported so getWithMetadata always returns null, and list operations return all matching keys with no pagination.

Cloudflare positions the mode for infrequently updated application configuration read on the hot path of requests, such as feature flags and settings that should be available globally almost instantly after they are written. The company notes the mode is not a fit for every type of data.

Pricing and availability

KV Instant is billed in three dimensions: storage, class A operations (put, delete, list) and class B operations (get). Reads cost 60% less than classic Workers KV, at $0.20 per million requests versus $0.50, while class A operations cost $0.10 per operation and storage is priced at $100 per MB per month. Cloudflare continues to recommend classic Workers KV for large or frequently updated datasets.

Each key can be up to 300 bytes, a namespace holds up to 10,000 key-value pairs and cannot exceed 1 megabyte, and writes are limited to one per namespace per second. KV Instant is launching in private beta, and Cloudflare is inviting customers to sign up.