Announcing Cloudflare K2: serverless event streams
Cloudflare launches K2, a serverless durable event streaming primitive on its Developer Platform. The service stores events in an ordered log on R2 object storage, decoupling producers from consumers to prevent data loss during downtime. It supports independent reading patterns and long-term retention, offering a Kafka-like alternative optimized for edge architectures across 335 cities.
Cloudflare explains that traditional RPC setups require producers and consumers to match both capacity and timing, otherwise excess data or downstream outages cause event loss, especially when several consumers need separate processing. To address this, they introduced K2, a server‑less, durable event‑streaming primitive that buffers writes and lets independent readers consume at their own speed. K2 stores events in an ordered log built on R2 object storage, providing massive scalability, strong consistency and long‑term retention so that downtime does not discard data, though initial produce latency reaches roughly one second at the 99th percentile. The service was created to supply a reliable edge buffer for Basin Pipelines, avoiding the need for conventional systems like Kafka that cannot run on Cloudflare’s globally distributed, often‑ephemeral infrastructure. K2 differs from Queues and Pipelines by focusing on high‑volume batch movement, fan‑out delivery, and historical storage rather than per‑item retries or direct object‑store ingestion.