- Free allowance
- Free $0: 1M credits a month, 3 concurrent sandboxes, no credit card required.
- Verdict
- caveatusable, with a named limit or an unprobed read path
- Cost
- free tier
- Identity
- emailno card, no phone
- Binding limit
- volume-quota1M credits a month on the free tier (USD 1 of usage); 10M on the USD 10 plan; 50M on the USD 50 plan
- Evidence
- documented5 sources; a first-party page was read and the sentence quoted
- Freshness
- stale on 2026-12-05checked 2026-11-04 (live); stale on 2026-12-05
| Free tier | Free $0: 1M credits a month, 3 concurrent sandboxes, no credit card required. 1M credits = USD 1, and the meter is billed per second at USD 0.0252 per vCPU-hour. unit mixed; metered on wall-clock; a monthly credit allowance equal to USD 1 of CPU time |
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| Price | none stated |
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| Limits | - volume-quota (binding) 1M credits a month on the free tier (USD 1 of usage); 10M on the USD 10 plan; 50M on the USD 50 plan source
- request-rate 3 concurrent sandboxes on free, 10 on the USD 10 plan, 1,000+ on Pro source
'No duration limits' and '~1s cold start' are the advertised shape. Auto top-up adds 1M credits (USD 1) when the balance runs low, which quietly converts a free tier into a paid one. |
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| Binding | volume-quota USD 1 of CPU credit is spent in about 39 vCPU-hours at the published rate, so an always-on 1 vCPU sandbox exhausts the free month in under two days. |
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| Identity | email 'No credit card required' on the Free plan, with a free API key issued at app.simplesandbox.dev. Card types for paid plans and any authorisation hold are not stated on the page read. |
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| Egress | No network fees: the pricing docs state billing is per-millisecond for compute and memory with no network fees; no traffic allowance is stated. |
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| Per-object cap | not applicable: the unit is a sandbox, not an object; no memory or disk allocation is published per sandbox |
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| Retention | The sandbox advertises 'No duration limits'. Persistent volumes are 1-100 GB, one per sandbox, single attachment, 'currently free only during beta' with future pricing unpublished. |
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| Interface | rest, cli TypeScript/Node SDK ('import { Sandbox } from '@simplesandbox/sdk')') and a REST API, with a free API key issued from the app. |
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| Tooling | The vendor SDK; the sandboxes run on Fly.io infrastructure under the vendor's own isolation. |
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| Composes with | A genuinely free, no-card code-execution endpoint with a USD 1 monthly credit is useful as a fallback executor but not as a machine: 1M credits buys about 39 vCPU-hours of CPU time and the memory meter is not published, so it cannot be sized as an always-on box. |
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| Reliability | No reliability event observed; the platform is a thin layer over Fly.io Machines, so its availability follows a third party's. |
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| Notes | Arithmetic from the published CPU rate alone: 1 vCPU × 730 h × USD 0.0252 = USD 18.396 a month of CPU time, before any memory charge, which the page does not publish. That number is deliberately not promoted to m24h_usd because a record cannot claim a 24/7 total from one of two meters. The free allowance is USD 1, which is 39.7 vCPU-hours. Region and egress are unverified. |
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| Evidence note | documented The credit price, the CPU rate, the plan prices, the concurrency caps and the no-card claim are quoted from the vendor's homepage read. The memory meter and the disk rate are not published, so no 24/7 total for a shape is recorded: the vCPU figure alone would understate the bill. What would raise it: the docs' billing page, or an account that reads the meter. |
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| Parsed numbers | |
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