AI context container provider Wire is moving its core runtime off Cloudflare Durable Objects (DOs) to a custom-built solution running on Fly Machines. While Wire continues to leverage Cloudflare Workers for its API, frontends, and control plane, the company found DOs' architectural limits incompatible with its demanding AI agent workloads.

Key issues included the inability to embed vector indexes directly within DOs, forcing a network hop to Cloudflare Vectorize. This latency, combined with a distributed compute model where container logic often ran far from its data, impacted retrieval performance. Wire also sought dedicated capacity and placement closer to users, which DOs do not offer. The new runtime embeds the sqlite-vec index directly into SQLite files, enabling in-process retrieval. This change nearly doubled recall@5 performance from 78.1% to 89.1% and reduced warm tool call latency from 0.4 seconds to 0.3 seconds, with spikes dropping from over 2 seconds to steadier performance.

Wire's new data plane uses Bun on Fly Machines, with each organization running its containers in a dedicated host process. Snapshots are sent to object storage for byte-for-byte rebuilds. While DOs provide free durability and single-writer consistency, Wire is now implementing continuous WAL shipping to ensure data resilience. The company plans to open-source the container runtime after a successful production migration.