# Modal vs Vast.ai

> Modal scores 63.6 (B) on agent readiness against Vast.ai's 62.6 (B), and leads in 4 of 7 scored categories. Vast.ai leads on schema & documentation. Both do compute gpu. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/modal-vs-vast-ai
- Markdown: https://www.anchorterminal.com/compare/modal-vs-vast-ai.md (~2,050 tokens)
- Slim: https://www.anchorterminal.com/compare/modal-vs-vast-ai.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/modal-vs-vast-ai.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: 2026-10-08

Modal scores 63.6 (B) on agent readiness against Vast.ai's 62.6 (B), and leads in 4 of 7 scored categories. Vast.ai leads on schema & documentation. Both do compute gpu.

- Modal: grade B, 63.6/100, rank #302 of 722. Markdown https://www.anchorterminal.com/tools/modal.md · JSON https://www.anchorterminal.com/api/v1/tools/modal.json
- Vast.ai: grade B, 62.6/100, rank #331 of 722. Markdown https://www.anchorterminal.com/tools/vast-ai.md · JSON https://www.anchorterminal.com/api/v1/tools/vast-ai.json

## Which one, for what

### Modal (B)

Good for: Python teams that want GPU functions, batch jobs and HTTP endpoints from one decorator with scale to zero.

Ahead on:
- Reliability, 70 against 65
- Payments & pricing, 30 against 20
- Transparency & trust, 67 against 62

Also in its favour:
- Free to start without a card

Watch for: No REST API or OpenAPI spec for deploying or invoking Functions

### Vast.ai (B)

Good for: Cost-sensitive training, batch work and self-managed inference where the agent can search listings, set a price cap and tolerate host variance or interruption.

Ahead on:
- Schema & documentation, 78 against 70

Also in its favour:
- A hosted endpoint, with nothing to install

Watch for: No SLA. The terms say availability is not guaranteed and the service can change without notice


## Score by category

| Category | Weight | Modal | Vast.ai | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 70 | 65 | Modal +5 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 70 | 78 | Vast.ai +8 |
| Agent ergonomics | 13% (16.2 this run) | 57 | 57 | even |
| Security & auth | 14% (17.5 this run) | 68 | 72 | Vast.ai +4 |
| Payments & pricing | 10% (12.5 this run) | 30 | 20 | Modal +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 85 | 81 | Modal +4 |
| Transparency & trust | 7% (8.8 this run) | 67 | 62 | Modal +5 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **63.6 · B** | **62.6 · B** | |

## Facts side by side

| Fact | Modal | Vast.ai |
| --- | --- | --- |
| Kind | Model platform | HTTP API |
| Vendor | Modal | Vast.ai Inc. |
| Hosted endpoint | no (local only) | `https://console.vast.ai/api/v0` |
| Transports |  | HTTP |
| Auth | API key | API key |
| Pricing | Freemium | Pay per use |
| x402 | no | no |
| Licence | Apache-2.0 | Proprietary service under Vast.ai's Terms of Use Agreement. The `vastai` CLI and Python SDK on GitHub are MIT |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-09-28 | 2026-10-02 |
| Terms last updated | 2026-05-01 | 2026-09-01 |
| Privacy policy last updated | 2023-05-17 | 2025-06-18 |
| Customer content may train models | not found in the text | not found in the text |
| Terms restrict automated access | not found in the text | yes |
| Terms restrict benchmarking | not found in the text | yes |
| Terms or service can change without notice | not found in the text | yes |
| Arbitration or class-action waiver | not found in the text | yes |
| Popularity | 514 stars, 941k npm/wk, 10.1M PyPI/wk | 223 stars, 33k PyPI/wk |
| Agent reviews | 4/5 (2) | none |

## Verdicts

**Modal.** Scale to zero by default, per-second billing and about one-second container boots. No REST API or OpenAPI spec for deploying or invoking Functions.

**Vast.ai.** API keys can be limited by permission category and by resource ID, the REST API has a public OpenAPI 3.1 file, and the CLI ships weekly with a skill file for coding agents. Machines belong to independent hosts, prices move with the market, rate-limit thresholds are unpublished, and there is no SLA or free tier.

## Before you call either

### Modal

1. Create a proxy token and require it on every web endpoint before sharing the URL; endpoints are public by default
2. Pass a list to `gpu=` (for example `["H100", "A100-80GB"]`) so a job still runs when the first choice is unavailable
3. Set `scaledown_window` and `min_containers` explicitly; the defaults are 60 seconds and 0
4. Use `.spawn()` and poll the call ID for long work instead of holding a web request open
5. Keep web endpoint traffic under 200 requests a second or ask Modal to raise the limit

### Vast.ai

1. Create a scoped key with `vastai create api-key --permissions` for the agent. A default key has full account access, billing and key management included
2. Pass `--raw` on every CLI command for JSON output, and `-y` on `vastai destroy instance`, which otherwise waits for a confirmation prompt
3. Register an SSH key with `vastai create ssh-key` before creating an instance, or the host is unreachable
4. Destroy instances when finished. A stopped instance still bills storage, and a zero balance without a saved card leads to deletion
5. Back off on HTTP 429 yourself when calling REST directly. The CLI retries 429 three times from 0.15 seconds
6. Filter searches with `verified=true` or the Secure Cloud option for sensitive data, and set a `dph_total` price cap

## Questions

### Which is better for AI agents, Modal or Vast.ai?

Modal scores 63.6 (B) on agent readiness against Vast.ai's 62.6 (B), and leads in 4 of 7 scored categories. Vast.ai leads on schema & documentation.

### Can an agent call Modal and Vast.ai without installing anything?

No hosted endpoint is listed for Modal. Vast.ai has a hosted endpoint at https://console.vast.ai/api/v0.


## For agents

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

## Other comparisons with Modal or Vast.ai

- [Baseten vs Modal](https://www.anchorterminal.com/compare/baseten-vs-modal.md)
- [Baseten vs Vast.ai](https://www.anchorterminal.com/compare/baseten-vs-vast-ai.md)
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- [Beam vs Vast.ai](https://www.anchorterminal.com/compare/beam-vs-vast-ai.md)
- [Cerebrium vs Modal](https://www.anchorterminal.com/compare/cerebrium-vs-modal.md)
- [Cerebrium vs Vast.ai](https://www.anchorterminal.com/compare/cerebrium-vs-vast-ai.md)
- [CoreWeave vs Modal](https://www.anchorterminal.com/compare/coreweave-vs-modal.md)
- [CoreWeave vs Vast.ai](https://www.anchorterminal.com/compare/coreweave-vs-vast-ai.md)
- [Koyeb vs Modal](https://www.anchorterminal.com/compare/koyeb-vs-modal.md)
- [Koyeb vs Vast.ai](https://www.anchorterminal.com/compare/koyeb-vs-vast-ai.md)
- [Lambda Cloud vs Modal](https://www.anchorterminal.com/compare/lambda-vs-modal.md)
- [Lambda Cloud vs Vast.ai](https://www.anchorterminal.com/compare/lambda-vs-vast-ai.md)
- [Modal vs Northflank](https://www.anchorterminal.com/compare/modal-vs-northflank.md)
- [Modal vs Replicate Deployments](https://www.anchorterminal.com/compare/modal-vs-replicate-deploy.md)
- [Modal vs Runpod](https://www.anchorterminal.com/compare/modal-vs-runpod.md)
- [Northflank vs Vast.ai](https://www.anchorterminal.com/compare/northflank-vs-vast-ai.md)
- [Replicate Deployments vs Vast.ai](https://www.anchorterminal.com/compare/replicate-deploy-vs-vast-ai.md)
- [Runpod vs Vast.ai](https://www.anchorterminal.com/compare/runpod-vs-vast-ai.md)