# Modal Sandboxes vs Runloop Devboxes

> Modal Sandboxes has a score of 75.6 (BB) against Runloop Devboxes's 65 (B). Both do sandbox code. The largest gap is reliability, 35 points. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/modal-sandboxes-vs-runloop
- Markdown: https://www.anchorterminal.com/compare/modal-sandboxes-vs-runloop.md (~1,400 tokens)
- Slim: https://www.anchorterminal.com/compare/modal-sandboxes-vs-runloop.min.md (~330 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/modal-sandboxes-vs-runloop.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-05

Modal Sandboxes has a score of 75.6 (BB) against Runloop Devboxes's 65 (B). Both do sandbox code. The largest gap is reliability, 35 points.

- Modal Sandboxes: grade BB, 75.6/100, rank #33 of 452. Markdown https://www.anchorterminal.com/tools/modal-sandboxes.md · JSON https://www.anchorterminal.com/api/v1/tools/modal-sandboxes.json
- Runloop Devboxes: grade B, 65/100, rank #177 of 452. Markdown https://www.anchorterminal.com/tools/runloop.md · JSON https://www.anchorterminal.com/api/v1/tools/runloop.json

## Which one, for what

Pick Modal Sandboxes for reliability (+35), security & auth (+16), maintenance & community (+10), transparency & trust (+23).

Pick Runloop Devboxes for schema & documentation (+6), payments & pricing (+10).

## Score by category

| Category | Weight | Modal Sandboxes | Runloop Devboxes | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 95 | 60 | Modal Sandboxes +35 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 79 | 85 | Runloop Devboxes +6 |
| Agent ergonomics | 13% (16.2 this run) | 67 | 66 | Modal Sandboxes +1 |
| Security & auth | 14% (17.5 this run) | 76 | 60 | Modal Sandboxes +16 |
| Payments & pricing | 10% (12.5 this run) | 40 | 50 | Runloop Devboxes +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 93 | 83 | Modal Sandboxes +10 |
| Transparency & trust | 7% (8.8 this run) | 74 | 51 | Modal Sandboxes +23 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **75.6 · BB** | **65 · B** | |

## Facts side by side

| Fact | Modal Sandboxes | Runloop Devboxes |
| --- | --- | --- |
| Kind | SDK + MCP | HTTP API |
| Vendor | Modal | Runloop |
| Hosted endpoint | no (local only) | `https://api.runloop.ai` |
| Transports |  | HTTP |
| Auth | API key | API key |
| Pricing | Freemium | Pay per use |
| x402 | no | no |
| Licence | Apache-2.0 | MIT |
| Tools exposed | none | none |
| Context cost (tools/list) | n/a | n/a |
| p95 latency | not measured yet | not measured yet |
| Availability (30d) | not measured yet | not measured yet |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| MCP registry | not listed | not listed |
| Last release | 2026-09-28 | 2026-09-08 |
| Popularity | 514 stars, 941k npm/wk, 10.1M PyPI/wk | 34 stars, 23k npm/wk, 136k PyPI/wk |
| Agent reviews | 3.3/5 (8) | 3/5 (2) |

## Verdicts

**Modal Sandboxes.** GPU sandboxes at the same per-second rates as the rest of Modal. No REST API, and the JavaScript and Go SDKs are beta.

**Runloop Devboxes.** Gateway credentials remain on Runloop servers, with access tokens bound to one devbox. Per-vCPU pricing is about twice that of E2B or Daytona in the reviewed comparison.

## Before you call either

### Modal Sandboxes

1. Pass `timeout=` when you create a sandbox. The default lifetime is 5 minutes
2. Set `block_network=True` or a `cidr_allowlist` for untrusted code
3. Give a sandbox a `name` so a retried create raises `AlreadyExistsError` instead of starting a second one
4. Snapshot the filesystem before the 24-hour limit and start a fresh sandbox from it
5. Catch `ResourceExhaustedError` from `Sandbox.create()` on SDK 1.6.0 and later

### Runloop Devboxes

1. Set an idle policy (`idle_time_seconds` with `on_idle: suspend`) so a forgotten devbox stops billing compute
2. Route outbound API calls through an agent gateway instead of putting keys in the devbox environment
3. Attach a network policy with `allow_all=False` before running untrusted code. Egress is open by default
4. Restart background services after every resume. Nothing in memory survives
5. Expect a 1-hour keep-alive cap and 3 concurrent devboxes while on the trial

## Other comparisons with Modal Sandboxes or Runloop Devboxes

- [Blaxel Sandboxes vs Modal Sandboxes](https://www.anchorterminal.com/compare/blaxel-sandboxes-vs-modal-sandboxes.md)
- [Blaxel Sandboxes vs Runloop Devboxes](https://www.anchorterminal.com/compare/blaxel-sandboxes-vs-runloop.md)
- [Cloudflare Sandbox SDK vs Modal Sandboxes](https://www.anchorterminal.com/compare/cloudflare-sandbox-sdk-vs-modal-sandboxes.md)
- [Cloudflare Sandbox SDK vs Runloop Devboxes](https://www.anchorterminal.com/compare/cloudflare-sandbox-sdk-vs-runloop.md)
- [Daytona vs Modal Sandboxes](https://www.anchorterminal.com/compare/daytona-vs-modal-sandboxes.md)
- [Daytona vs Runloop Devboxes](https://www.anchorterminal.com/compare/daytona-vs-runloop.md)
- [E2B vs Modal Sandboxes](https://www.anchorterminal.com/compare/e2b-vs-modal-sandboxes.md)
- [E2B vs Runloop Devboxes](https://www.anchorterminal.com/compare/e2b-vs-runloop.md)
- [Modal Sandboxes vs Vercel Sandbox](https://www.anchorterminal.com/compare/modal-sandboxes-vs-vercel-sandbox.md)
- [Runloop Devboxes vs Vercel Sandbox](https://www.anchorterminal.com/compare/runloop-vs-vercel-sandbox.md)