Cloudflare Launches Workers KV Instant for 100x Faster Global Config

What happened

Cloudflare introduced Workers KV Instant, a new mode for its Workers KV service that leverages Quicksilver, Cloudflare's internal key-value store used across its global infrastructure. Workers KV has been available since 2018 and serves use cases like static assets and user configuration. Quicksilver, built in 2020 for fast global replication, has never been offered to customers until now. KV Instant exposes Quicksilver capabilities through the familiar Workers KV API, targeting read-heavy workloads with infrequently updated data.

Performance and capabilities

KV Instant achieves p99 read latency of 1.62 milliseconds and p95 read latency measured in microseconds, representing over 100 times faster reads than classic Workers KV's 287 millisecond p99. Writes propagate to all edge locations with p99 replication of 256 milliseconds, more than 20 times faster than classic mode. Median write replication is 107 milliseconds. The service is designed for application flags and settings that must be globally available with minimal latency after updates.

The API remains largely unchanged from classic Workers KV, supporting get(), put(), list(), and delete() operations. Three key differences exist: KV Instant mode must be explicitly specified when creating a namespace using the "mode": "instant" attribute; metadata operations are not supported, so getWithMetadata() always returns null; and list operations return all matching keys without pagination rather than in pages. Namespaces can store up to 10,000 key-value pairs with keys up to 300 bytes and values of any size within the namespace's one-megabyte limit.

Pricing and constraints

KV Instant read operations (Class B) cost $0.20 per million requests, 60% cheaper than classic Workers KV's $0.50 per million. However, write operations (Class A: put, delete, list) are significantly more expensive at $0.10 per operation compared to classic mode's $5.00 per million. Storage costs $100 per MB per month, roughly 200 times more than classic KV's $0.50 per GB per month. These pricing differences reflect KV Instant's design for read-heavy, small-data workloads. Write frequency is limited to one write per namespace per second, similar to classic KV's per-key restriction, to ensure consistent update ordering. Each list request counts as one Class A operation regardless of keys returned.

Who it affects and use cases

KV Instant is optimized for infrequently-updated application configuration—the same data Cloudflare uses Quicksilver for internally. Developers using Workers for feature flags, routing rules, or product launch toggles that need global instant availability would benefit most. The example provided shows a product launch scenario where a flag read on every request must update instantly when toggled. Teams with large-scale, frequently-written data should continue using classic Workers KV, as write costs and per-namespace throughput limits make KV Instant unsuitable for high-frequency mutations.

Availability and next steps

Workers KV Instant is launching in private beta today. Developers interested in testing the service can sign up for the private beta through Cloudflare's announcement. The service will expand to wider availability following feedback from beta participants. Existing Workers KV users do not need to migrate; both modes will coexist, allowing teams to choose the most appropriate mode for each namespace's access patterns and update frequency.

Source

AI-assisted, verified against the source. This post was drafted with AI from the primary source linked above and checked automatically against it. For anything you depend on, read the original.