Why we're moving Wire off Cloudflare Durable Objects | Wire Engineering<br>Why we're moving Wire off Cloudflare Durable Objects<br>JP · July 7, 2026 · 4 min read

Wire is context containers for AI agents: isolated stores of processed knowledge (entries, embeddings, knowledge and provenance graphs) queried over MCP. Since day one, every container has been a Cloudflare Durable Object.

That is changing. We rebuilt the container runtime from the ground up, benchmarked it against the old one on identical data (same container, same questions, same judge), and the first workspaces have moved to a data plane we built ourselves. This is the story behind the benchmark.

This is not a “we left Cloudflare” post. I love Cloudflare and Wire stays on it everywhere it can: the API, the frontends, the control plane, and processing all still run on Workers. Durable Objects are close to a perfect fit for thousands of small, mostly idle stateful units, and I have not seen anything faster to build on. We left because of four structural limits, not reliability.

1. The vector index lived outside the object

Retrieval is the most important thing a container does, and the embeddings lived in Vectorize, a separate service. That is a network hop on the hottest path and a second copy of state that can drift. DO SQLite cannot load extensions, so the index could never come inside.

2. We wanted the compute next to the data

Retrieval is a multi-stage pipeline: hybrid candidate generation, fusion, query expansion, and a wide rerank. On Durable Objects only a thin slice of that could run where the data lives; the rest was exported to services around the object. Agents call containers inside tool loops, and every hop’s variance lands on the critical path.

3. Placement is creation-time only, and compute is always shared

Location hints exist at creation, but an object never moves afterward, so a container created from London serves an agent fleet in Virginia forever. And you cannot buy dedicated capacity for one tenant. We wanted placement that follows the callers, and isolation as a product tier: paid workspaces get their own process and machines.

4. You can’t self-host a Durable Object

Regulated teams keep asking to run containers on infrastructure they control. A runtime that only exists on Cloudflare can’t.

What we built

Each organization gets one host process (Bun) on Fly Machines for all its containers. A container is one SQLite file with the vector index embedded via sqlite-vec, so candidate retrieval runs in-process; the model calls, query embedding and the rerank, still go out to inference. Snapshots go to object storage, so a container rebuilds byte for byte anywhere. A per-region router places containers near the caller, and the control plane talks to the data plane via signed requests and never touches container content.

Warm tool calls hold roughly 0.3 seconds, steady, versus roughly 0.4 seconds with spikes past 2 seconds before. An idle container wakes in 1.4 seconds end to end versus 3.7. To be precise about that last number: it was never “Durable Object cold start,” isolates wake in milliseconds. The 3.7 seconds was our own stack reassembling itself.

Nothing changed at the surface. Same container URLs, same five MCP tools, same REST API, same response shapes. Agents keep calling the same address; requests to a migrated container are just answered by the new runtime.

Buying durability back

Durable Objects hand you durability and single-writer consistency for free, and leaving means buying them back. Cloudflare replicates every DO storage write before acking it. Our first cut was only “durable at next checkpoint,” and soak tests that kill machines under load showed exactly what that means: a handful of acked writes, gone. The real fix is continuous WAL shipping. A write does not ack until its WAL frame is in object storage; group commit keeps that to about 100 ms, and a dead machine cannot take acked writes with it.

If you do not need the four things above, stay on the platform.

The honest read on the numbers

The retrieval gains (recall@5 from 78.1% to 89.1%) are not all architecture; we also moved to a newer embedding model. What the architecture does is make the expensive parts cheap: in-process retrieval lets you over-fetch and rerank wide, and per-container indexes are small enough for exact nearest-neighbor search. The full before/after tables and methodology are in the benchmark write-up.

Where it stands

The new runtime is in beta: our preview environment plus opt-in production workspaces today, with full production migration following as our durability tripwires stay green. Once the cutover is done, we plan to open-source the container runtime. We should ship the code we actually run.

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