celld

Why it's ranked here

The strongest reason to consider celld is its unusually explicit distributed-systems design. Durable writes wait for object-storage replication, ownership uses atomic conditional writes, and failures are tested through differential runtime checks, deterministic simulation, and live fleet fault injection. The verdict remains cautious because the project calls itself alpha and documents significant compatibility and security boundaries.

What's good

The failure model is concrete. A node that cannot replicate fences itself, acknowledged writes pass through an output gate, and ownership epochs block former owners from serving stale state. Compatibility gaps are documented API by API and unknown deployment keys fail loudly. Fleet diagnostics continue after individual failures and report lease, address, reachability, authentication, protocol, resource, and shedding problems.

Tradeoffs

Peer traffic uses plain HTTP, so operators must provide a trusted private network or encrypted overlay. celld does not authenticate application users or terminate public TLS. Each fleet runs one application and lacks managed ingress, global placement, and multi-tenant scheduling. Cloudflare compatibility is partial: KV, R2, Cache, cron triggers, several handlers, and many Node modules are absent or stubbed. Pressure shedding is opt-in, and updates are manual.

How to use it well

Use celld when a team has a Wrangler-based Worker application, wants control of its machines and storage, and can operate private networking, ingress, credentials, capacity headroom, and manual upgrades. Model state around many named Durable Objects, test against the documented compatibility surface, and reserve spare capacity for node loss. Do not treat it as a managed Cloudflare replacement, authentication layer, TLS endpoint, general blob store, or hostile multi-tenant platform.

Observed

License

Apache-2.0

Primary language

Rust, organized as a Cargo workspace

Installation

Downloadable binary installer, source build with Cargo, and a container image

Interface

Command-line daemon with deploy, diagnose, runtime, and help commands

Deployment input

Wrangler JSON or JSONC projects; Worker code requires esbuild on PATH

Prebuilt platforms

Container image for Linux x86-64 and ARM64; Windows is unavailable, and Intel Macs require a source build

Runtime surface

Module Workers, Durable Objects, static assets, service bindings, JavaScript RPC, alarms, and WebSockets

License contribution model

Pull requests are disabled; focused patches are accepted by email under the stated contributor agreement