celld: self-hosted Durable Objects
celld is a serious attempt to make the Durable Objects programming model self-hostable: V8 Workers, one SQLite database per object, S3-compatible storage as the durable source of truth, and no separate control plane or consensus service.
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Logged at IST: 2026-08-05 20:19 IST
What it is: Ryan Dahl's launch post for celld, a Deno open-source daemon for self-hosted, distributed Durable Objects and Workers.
Gist: celld aims to run the Cloudflare Workers and Durable Objects programming model on your own machines. Each object is its own SQLite database, addressed by name and replicated to an S3-compatible bucket. The fleet coordinates through that bucket alone, using object-storage compare-and-swap so one node owns a cell at a time without a separate control plane, membership protocol, failure detector, or consensus service.
The tweet's shape is deliberately concrete: V8 + S3 + SQLite + LTX + Tokio, programmed with Cloudflare Workers and Durable Object JavaScript APIs and config. It claims durable writes before acknowledgement, RPO=0, roughly 4 MB memory overhead per resident cell, and near-zero cost for hibernated cells beyond S3 storage.
The attached charts make the cost argument. Dahl compares monthly cost against resident fleet size, showing celld staying flat at small fleet sizes and much cheaper at larger resident-cell counts than Cloudflare Durable Objects in the shown model. The characteristics table lists one epoch-fenced writer per cell, zero acknowledged writes lost on kill, about 90 ms region-local durable write latency, about 20 s failover after node loss with no lost writes, 0.2 / 0.3 ms warm stateless p50 / p99, about 94k req/s per worker thread, about 4 ms to wake a hibernated cell, 1,000 resident cells per 8 GB node, and about $0.05 per resident cell-month.
Newsletter angle: This is an important systems counterpoint to managed serverless primitives: the Durable Objects model may be escaping Cloudflare as a self-hostable architecture, with object storage as the coordination and durability substrate.