Cloudflare has opened access to Quicksilver, its internal configuration store, for the first time by packaging it as a new offering called KV Instant. Read operations complete in 1.62 milliseconds at the 99th percentile, compared with 287 milliseconds for the company's classic KV service. Quicksilver was built in 2020 and handles lookups for nearly every request hitting Cloudflare's network, but it was never sold to customers until now. The product arrives as a second mode within the existing Workers KV interface, with dramatically different performance characteristics and economics.
The published benchmarks, measured across more than 300 edge locations worldwide, show Instant mode resolving reads at the 99th percentile in 1.62 ms versus 287 ms for classic mode. Write replication happens with a median of 107 ms and a 99th percentile of 256 ms for Instant, while classic mode sees median replication under one second and 99th percentile replication at 4.38 seconds. Cloudflare notes it lacks sub-second measurement precision for classic replication lag, meaning those classic figures represent upper bounds rather than exact measurements. Reads at the 95th percentile in Instant mode clock in at microsecond speeds.
The constraints define the use case as tightly as the speed does. Each namespace holds a maximum of 10,000 key-value pairs totaling no more than one megabyte, with individual keys capped at 300 bytes. Writes are limited to one per namespace per second, a sharp contrast with classic KV's one write per key per second limit. Brendan Irvine-Broque, who works on Cloudflare's developer platform, explained the reasoning: "just like how we use Quicksilver ourselves, it's for small data that is read often and updated infrequently." He added that writes carry their cost because each one replicates a key to hundreds of locations. The pricing structure reinforces that model: reads run $0.20 per million (60% cheaper than classic KV), while writes cost $0.10 each compared with $5.00 per million in classic mode, and storage runs $100 per megabyte monthly versus $0.50 per gigabyte for classic.
The pricing and limits steer teams toward workloads that match Cloudflare's own internal usage pattern: configuration data, feature flags, routing tables, and agent settings that get read constantly but change rarely. Developer Benjie Malinao characterized it as "the config store agents actually need," pointing to sub-2 millisecond 99th percentile reads and global writes landing in roughly a quarter second at the 99th percentile, all without waiting on a time-to-live expiration. Session state, user records, and anything with frequent write activity won't fit the envelope. Cloudflare's own worked example describes a launch flag read on every request and flipped during a keynote—one key, one write, read everywhere immediately. Classic Workers KV, which launched in 2018, remains the recommended choice for large or frequently updated datasets, leaving the two modes under one API with opposite economics. KV Instant is currently in private beta with a sign-up form, and Cloudflare plans broader availability without specifying a general release date.
The question for platform teams isn't whether the latency improvement looks compelling on paper, but whether their access patterns can live within strict write throttling and tiny storage caps. Instant mode forces a trade-off between performance and flexibility that rewrites the traditional key-value calculus entirely.