Cloudflare Sandboxes

license

Proprietary

source

closed

service

proprietary Cloudflare edge (Workers/Durable Objects/Dynamic Worker Loader - no self-host of the isolate/container plane)

open-part

Sandbox SDK only (@cloudflare/sandbox Apache-2.0, cloudflare/sandbox-sdk on GitHub)

pricing

Workers paid plan, Dynamic Workers $0.002/unique-worker/day

Closed managed service. The Sandbox SDK is Apache-2.0, but execution requires Cloudflare's proprietary managed edge network (no self-host of the isolate/container plane); an open client SDK over a closed runtime is not open_core. Reclassified from open_core.

• https://github.com/cloudflare/sandbox-sdk recorded 2026-06-04

  Apache-2.0 SDK; runs on Cloudflare Containers/Workers/Durable Objects (managed edge)

• https://blog.cloudflare.com/dynamic-workers/ recorded 2026-06-04

  Dynamic Worker Loader open beta, isolate sandboxing, post-beta $0.002/worker/day pricing

npm @cloudflare/sandbox ~533k downloads in the last 30 days (npm registry API); Dynamic Workers in open beta to all paid Workers users with a named customer (Zite) reporting 'millions of execution requests daily.' Package pulls + young beta status => reach placed at 100K-1M (level 3); execution-request volume is per-customer, not distinct-user adoption.

• https://api.npmjs.org/downloads/point/last-month/@cloudflare/sandbox recorded 2026-06-04

  ~533,043 downloads May 4-Jun 2 2026

• https://blog.cloudflare.com/dynamic-workers/ recorded 2026-06-04

  open beta to all paid Workers users; Zite millions of execution requests/day

Distinctive isolate-based approach gives best-in-class cold-start and density on the JS/TS isolate path, plus a container path for arbitrary code; held at 4 because isolate sandboxing is JS/TS-centric (narrower than microVM any-image), Dynamic Workers is still open beta, and overall scale evidence is per-customer rather than category-leading. Scored as a combined product per the registry name. Independent ComputeSDK TTI benchmarks measure the container-backed sandbox path (what runs arbitrary code) at ~1.8s median cold-start, 18th of 19 sandbox providers, degrading to ~4.3s under 100-concurrent burst; the sub-ms figures apply to the JS/TS Dynamic Workers path, not the arbitrary-code sandbox the benchmark exercises. On measured full-sandbox latency alone this would be a 3; held at 4 on the strength of the dual isolate-plus-container isolation model.

• https://blog.cloudflare.com/dynamic-workers/ recorded 2026-06-04

  V8 isolate sandboxing, ~ms start, 100x faster/100x more memory-efficient than containers

• https://github.com/cloudflare/sandbox-sdk recorded 2026-06-04

  container-backed sandbox: run commands, manage files, background processes, expose services

• https://www.computesdk.com/benchmarks/sandboxes/ recorded 2026-07-09

  ComputeSDK TTI leaderboard (independent, 100 iters/day, 2026-07-09 run): container-backed sandbox median time-to-interactive ~1760ms sequential / ~4290ms burst @100 concurrent; 18th of 19 providers