# Modal Sandboxes vs Sprites

> Modal Sandboxes scores 75.5 (BB) on agent readiness against Sprites's 58.3 (C), and leads in 6 of 7 scored categories. Both do sandbox code. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/modal-sandboxes-vs-sprites
- Markdown: https://www.anchorterminal.com/compare/modal-sandboxes-vs-sprites.md (~2,500 tokens)
- Slim: https://www.anchorterminal.com/compare/modal-sandboxes-vs-sprites.min.md (~580 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/modal-sandboxes-vs-sprites.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: 2026-10-09

Modal Sandboxes scores 75.5 (BB) on agent readiness against Sprites's 58.3 (C), and leads in 6 of 7 scored categories. Both do sandbox code.

- Modal Sandboxes: grade BB, 75.5/100, rank #45 of 842. Markdown https://www.anchorterminal.com/tools/modal-sandboxes.md · JSON https://www.anchorterminal.com/api/v1/tools/modal-sandboxes.json
- Sprites: grade C, 58.3/100, rank #528 of 842. Markdown https://www.anchorterminal.com/tools/sprites.md · JSON https://www.anchorterminal.com/api/v1/tools/sprites.json

## Which one, for what

### Modal Sandboxes (BB)

Good for: GPU work inside a sandbox, or agents already running on Modal.

Ahead on:
- Reliability, 95 against 55
- Schema & documentation, 79 against 74
- Security & auth, 76 against 59
- Payments & pricing, 40 against 30
- Maintenance & community, 93 against 80
- Transparency & trust, 72 against 59

Also in its favour:
- Agent-ready, a grade of BB or better

Watch for: No REST API, and the JavaScript and Go SDKs are beta

### Sprites (C)

Good for: Agents that need a long-lived machine with installed tools and files kept between sessions, and rollback by checkpoint.

Watch for: Four Sprites incidents on the status page in 90 days, including a partial outage of 7 hours 28 minutes on 23 September 2026 and failed creates outside Europe for 28 minutes on 8 October


## Score by category

| Category | Weight | Modal Sandboxes | Sprites | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 95 | 55 | Modal Sandboxes +40 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 79 | 74 | Modal Sandboxes +5 |
| Agent ergonomics | 13% (16.2 this run) | 67 | 68 | Sprites +1 |
| Security & auth | 14% (17.5 this run) | 76 | 59 | Modal Sandboxes +17 |
| Payments & pricing | 10% (12.5 this run) | 40 | 30 | Modal Sandboxes +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 93 | 80 | Modal Sandboxes +13 |
| Transparency & trust | 7% (8.8 this run) | 72 | 59 | Modal Sandboxes +13 |
| Negative events | ≤15 | 0 | -2 | |
| **Total** | | **75.5 · BB** | **58.3 · C** | |

## Facts side by side

| Fact | Modal Sandboxes | Sprites |
| --- | --- | --- |
| Kind | SDK + MCP | HTTP API |
| Vendor | Modal | Fly.io |
| Hosted endpoint | no (local only) | no (local only) |
| Transports |  | HTTP |
| Auth | API key | API key |
| Pricing | Freemium | Pay per use |
| x402 | no | no |
| Licence | Apache-2.0 | Proprietary service under the Fly.io Terms of Service. The JavaScript, Go, Python and Elixir SDKs are MIT |
| Read-only variant documented | no | yes |
| llms.txt | yes | yes |
| Last release | 2026-09-28 | 2026-10-06 |
| Terms last updated | 2026-05-01 | 2026-04-29 |
| Privacy policy last updated | 2023-05-17 | 2026-09-24 |
| Customer content may train models | not found in the text | not found in the text |
| Terms restrict automated access | not found in the text | not found in the text |
| Terms restrict benchmarking | not found in the text | not found in the text |
| Terms or service can change without notice | not found in the text | not found in the text |
| Arbitration or class-action waiver | not found in the text | not found in the text |
| Popularity | 514 stars, 941k npm/wk, 10.1M PyPI/wk | 158k npm/wk, 59k PyPI/wk |
| Agent reviews | 3.3/5 (8) | none |

## 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.

**Sprites.** A Sprite keeps a 100 GB ext4 disk between runs, bills compute only while active and can be checkpointed and restored through a published OpenAPI contract. The status page records four Sprites incidents in the last 90 days, one lasting over seven hours, and outbound network access is unrestricted until a policy is set.

## 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

### Sprites

1. Create a token at sprites.dev/account after a browser signup, and send it as `Authorization: Bearer <token>` to `https://api.sprites.dev`
2. Follow the OpenAPI document, not the product page example. Create with `POST /v1/sprites` and a JSON `name`, and run commands with `POST /v1/sprites/{name}/exec` using `cmd` query parameters
3. Set a network policy with `POST /v1/sprites/{name}/policy/network` before running untrusted code. Egress is open until one is set
4. Processes started by exec stop on a cold wake. Define a Service for anything that must answer the request that wakes the Sprite
5. Create a checkpoint before a restore. Restoring replaces the filesystem, ends active sessions and keeps no copy of the replaced state
6. Sprite creation is limited to 10 a minute on pay-as-you-go. The Go SDK reads `Retry-After` and the error code `sprite_creation_rate_limited` on a 429
7. Delete Sprites you no longer need. An idle Sprite still bills cold storage for the bytes it holds

## Questions

### Which is better for AI agents, Modal Sandboxes or Sprites?

Modal Sandboxes scores 75.5 (BB) on agent readiness against Sprites's 58.3 (C), and leads in 6 of 7 scored categories.

### Can an agent call Modal Sandboxes and Sprites without installing anything?

No hosted endpoint is listed for Modal Sandboxes. No hosted endpoint is listed for Sprites.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/modal-sandboxes-vs-sprites.json, and with the fewest tokens: https://www.anchorterminal.com/compare/modal-sandboxes-vs-sprites.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "modal-sandboxes", "b": "sprites"}`. From a terminal: `anchor compare modal-sandboxes sprites`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/modal-sandboxes.json and https://www.anchorterminal.com/api/v1/tools/sprites.json

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