A New Mode for Workers KV

Cloudflare has announced Workers KV Instant, a new operational mode designed to push changes globally for instant availability while eliminating cold read penalties. Since its initial debut during Birthday Week in 2018, Workers KV has grown to become one of the most popular services on the company's Developer Platform. It has traditionally served as a reliable solution for quickly accessing data like static assets and user configurations that are written occasionally but read frequently.

While classic Workers KV handles a broad range of general workloads, developers have frequently requested access to Quicksilver, the high-speed key-value store that Cloudflare has utilized internally since introducing it in 2020. With the arrival of Workers KV Instant, developers can now leverage the performance characteristics of Quicksilver directly through the familiar Workers KV API.

Powered by Quicksilver v2 Architecture

Workers KV Instant is driven by Quicksilver v2, a globally distributed key-value store engineered by Cloudflare for low-latency access and rapid data propagation. According to the company, the new mode achieves read latency over 100 times faster than classic mode, resolving reads in under two milliseconds even at the 99th percentile (p99), with 95th percentile times measured in microseconds.

In addition to rapid reads, writes are propagated to the edge more than 20 times faster than classic mode. Approximately 99% of all writes replicate across more than 300 edge locations in roughly 250 milliseconds. These performance metrics make the system well-suited for applications requiring feature flags and configuration settings to update instantly across a global audience.

API Compatibility and Key Differences

Developers building with Workers KV Instant can continue using the core methods they already know, including get(), put(), list(), and delete(). However, because the underlying architecture differs significantly from classic mode, developers should review the official documentation to account for specific behavioral changes.

There are three primary distinctions when implementing KV Instant namespaces. First, developers must explicitly specify instant mode by passing the 'mode' attribute during namespace creation. Second, metadata is unsupported, meaning getWithMetadata calls always return null and put operations cannot accept metadata. Third, list operations return all matching keys in a namespace without pagination.

Pricing Structure and Resource Limits

Cloudflare has structured the pricing for Workers KV Instant to accommodate small, read-heavy workloads. Because data is propagated to every edge location using Quicksilver, Class B read operations cost 60% less than classic Workers KV default mode, billed at $0.20 per million keys requested.

Conversely, storage and Class A operations carry a higher cost. Storage is billed at $100 per megabyte monthly, with namespaces capped at 10,000 key-value pairs and a total size limit of one megabyte. Class A operations—including put, delete, and list—are charged at $0.10 per operation. Furthermore, write frequency is restricted to one write per namespace per second to maintain update order consistency through the system of record.

Private Beta Availability

Workers KV Instant is currently launching in a private beta phase. Cloudflare is inviting developers interested in testing the high-performance configuration store to apply and share details about their projects before a wider public rollout.

Sources

• Cloudflare BlogIntroducing Workers KV Instant — powered by Quicksilver