# ScaleDown vs Vela 2.0

> Vela 2.0 scores 66.5 (B) to ScaleDown's 48.6 (D) for decision models. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/scaledown-vs-vela
- Markdown: https://www.anchorterminal.com/compare/scaledown-vs-vela.md (~2,650 tokens)
- Slim: https://www.anchorterminal.com/compare/scaledown-vs-vela.min.md (~730 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/scaledown-vs-vela.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
- Licence: CC BY 4.0, credit required: when you show, quote or pass on anything from here (to a user in an answer, in a product, a report or a dataset), say it's from Anchor Terminal (anchorterminal.com) and link the page or API address you took it from. Reviews also credit their author.
- Updated: 2026-10-14

Vela 2.0 scores 66.5 (B) on agent readiness against ScaleDown's 48.6 (D), and leads in 6 of 7 scored categories. ScaleDown leads on transparency & trust. Both do decision models.

- ScaleDown: grade D, 48.6/100, rank #873 of 1084. Markdown https://www.anchorterminal.com/tools/scaledown.md · JSON https://www.anchorterminal.com/api/v1/tools/scaledown.json
- Vela 2.0: grade B, 66.5/100, rank #308 of 1084. Markdown https://www.anchorterminal.com/tools/vela.md · JSON https://www.anchorterminal.com/api/v1/tools/vela.json
- Best decision models for AI agents: https://www.anchorterminal.com/best/decision-models/index.md
- All 120 decisions comparisons: https://www.anchorterminal.com/compare/decision-models/index.md
- Best document parsing, OCR and extraction APIs for AI agents: https://www.anchorterminal.com/best/document-extraction/index.md
- All 124 documents comparisons: https://www.anchorterminal.com/compare/document-extraction/index.md

## Which one, for what

### ScaleDown (D)

Good for: Cheap, high-volume labelling, routing and yes or no checks where a probability is more useful than prose, and for pulling described fields with offsets from text, images or PDFs.

Ahead on:
- Transparency & trust, 54 against 48

Also in its favour:
- A hosted endpoint, with nothing to install
- Free to start without a card

Watch for: No status page, no published rate limits and no SLA outside enterprise contracts

### Vela 2.0 (B)

Good for: Self-hosted routing and guardrail checks in one call, where span offsets for personal data or unsupported claims matter.

Ahead on:
- Reliability, 57 against 20
- Schema & documentation, 78 against 69
- Security & auth, 60 against 48
- Payments & pricing, 60 against 40
- Maintenance & community, 84 against 56

Also in its favour:
- No key needed to call it
- Open source

Watch for: No version tags on the four Hub repositories, and the 4B and 9B weights were replaced in place on 3 October 2026


## Score by category

| Category | Weight | ScaleDown | Vela 2.0 | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 20 | 57 | Vela 2.0 +37 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 69 | 78 | Vela 2.0 +9 |
| Agent ergonomics | 13% (16.2 this run) | 76 | 79 | Vela 2.0 +3 |
| Security & auth | 14% (17.5 this run) | 48 | 60 | Vela 2.0 +12 |
| Payments & pricing | 10% (12.5 this run) | 40 | 60 | Vela 2.0 +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 56 | 84 | Vela 2.0 +28 |
| Transparency & trust | 7% (8.8 this run) | 54 | 48 | ScaleDown +6 |
| Negative events | ≤15 | -2 | 0 | |
| **Total** | | **48.6 · D** | **66.5 · B** | |

## Facts side by side

| Fact | ScaleDown | Vela 2.0 |
| --- | --- | --- |
| Kind | Model API | Model API |
| Vendor | Carbon ScaleDown, Inc. | vLLM Semantic Router project and KR Labs |
| Hosted endpoint | `https://api.scaledown.xyz` | no (local only) |
| Transports | HTTP | HTTP |
| Auth | API key | None |
| Pricing | Pay per use | Free |
| x402 | no | no |
| Licence | Proprietary hosted models under ScaleDown's Terms of Service. The langchain-scaledown integration is MIT | Apache-2.0 (weights, code and documentation). The 0.3B's tokeniser keeps the Gemma Terms of Use, and training data keeps its own licences |
| Read-only variant documented | no | no |
| llms.txt | yes | no |
| Last release | 2026-10-14 | 2026-10-06 |
| Terms last updated | couldn't be read | no document linked |
| Privacy policy last updated | couldn't be read | no document linked |
| Customer content may train models | couldn't be read |  |
| Terms restrict automated access | couldn't be read |  |
| Terms restrict benchmarking | couldn't be read |  |
| Terms or service can change without notice | couldn't be read |  |
| Arbitration or class-action waiver | couldn't be read |  |
| Popularity | 0 stars | 6.1k stars |

## Verdicts

**ScaleDown.** Classify answers Jev-shaped `choice`, `noul` and `score` questions with probabilities, and Extract returns values with confidences and character offsets, at $0.05 per million input tokens with output free. There is no status page, no published rate limit and no public changelog, and the site's compliance claims contradict each other.

**Vela 2.0.** One self-hosted call answers routing, prompt-attack, personal-data and unsupported-claim questions with probabilities and character offsets, under Apache-2.0 with SHA-256 manifests. The models are days old and carry no Hub version tags, and the three larger sizes keep 74 to 89 per cent of their Decision 2.0 bases on the Jev Decision Index by the authors' figures.

## Before you call either

### ScaleDown

1. Send several questions about one item in one `/v1/scaledown` call. Each becomes its own Classify call and the usage is summed
2. Pin `classify-1`, `extract-1` or `summarize-1` once you've tuned thresholds on your own labelled cases
3. Set `context_chars` to 0 and use `top_n` on Extract unless you need the 500 characters of context each side
4. Set `reasoning: false` on /classify when you only need the label. The reasoning call bills its input at 2x
5. Back off and retry on 429, 502 and 504. No limits are published and calls have no side effects

### Vela 2.0

1. Pin a commit hash with `revision=` when loading from the Hub. The repositories have no tags and `main` has changed since launch
2. Send the served name in `model`, for example `vllm-sr/Vela-2.0-4B`. The bundled server answers 422 to any other name
3. Name span questions `pii`, `halu` or `toxic`, or set `"head": "router"`, to get the trained router head. Other labels go to the broad head
4. Keep input under 16,384 tokens a sequence (8,192 on the 0.3B). The bundled server answers 413 when the questions alone don't fit
5. Set `VELA2_API_KEY` before binding the bundled server beyond 127.0.0.1, and keep the model runtime on a trusted network

## Questions

### Which is better for AI agents, ScaleDown or Vela 2.0?

Vela 2.0 scores 66.5 (B) on agent readiness against ScaleDown's 48.6 (D), and leads in 6 of 7 scored categories. ScaleDown leads on transparency & trust.

### Do ScaleDown and Vela 2.0 need an API key?

ScaleDown needs an API key. Vela 2.0 needs no key.

### Can an agent call ScaleDown and Vela 2.0 without installing anything?

ScaleDown has a hosted endpoint at https://api.scaledown.xyz. No hosted endpoint is listed for Vela 2.0.

### Are ScaleDown and Vela 2.0 open source?

No open-source release is listed for ScaleDown. Vela 2.0 is open source (Apache-2.0 (weights, code and documentation). The 0.3B's tokeniser keeps the Gemma Terms of Use, and training data keeps its own licences).


## For agents

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

## Other comparisons with ScaleDown or Vela 2.0

- [Celeris-1 Decision vs ScaleDown](https://www.anchorterminal.com/compare/celeris-1-decision-vs-scaledown.md)
- [Celeris-1 Decision vs Vela 2.0](https://www.anchorterminal.com/compare/celeris-1-decision-vs-vela.md)
- [Clef vs ScaleDown](https://www.anchorterminal.com/compare/cloudflare-clef-vs-scaledown.md)
- [Clef vs Vela 2.0](https://www.anchorterminal.com/compare/cloudflare-clef-vs-vela.md)
- [Laya vs ScaleDown](https://www.anchorterminal.com/compare/convai-laya-vs-scaledown.md)
- [Laya vs Vela 2.0](https://www.anchorterminal.com/compare/convai-laya-vs-vela.md)
- [Decider vs ScaleDown](https://www.anchorterminal.com/compare/decider-vs-scaledown.md)
- [Decider vs Vela 2.0](https://www.anchorterminal.com/compare/decider-vs-vela.md)
- [Decision 3.0 vs ScaleDown](https://www.anchorterminal.com/compare/decision-3-vs-scaledown.md)
- [Decision 3.0 vs Vela 2.0](https://www.anchorterminal.com/compare/decision-3-vs-vela.md)
- [GLiClass vs ScaleDown](https://www.anchorterminal.com/compare/gliclass-vs-scaledown.md)
- [GLiClass vs Vela 2.0](https://www.anchorterminal.com/compare/gliclass-vs-vela.md)
- [Kev vs ScaleDown](https://www.anchorterminal.com/compare/jaredpalmer-kev-vs-scaledown.md)
- [Kev vs Vela 2.0](https://www.anchorterminal.com/compare/jaredpalmer-kev-vs-vela.md)
- [Liquid d1 vs ScaleDown](https://www.anchorterminal.com/compare/liquid-d1-vs-scaledown.md)
- [Liquid d1 vs Vela 2.0](https://www.anchorterminal.com/compare/liquid-d1-vs-vela.md)
- [Microsoft-Decision-1 vs ScaleDown](https://www.anchorterminal.com/compare/microsoft-decision-1-vs-scaledown.md)
- [Microsoft-Decision-1 vs Vela 2.0](https://www.anchorterminal.com/compare/microsoft-decision-1-vs-vela.md)
- [Drex 1.5 vs ScaleDown](https://www.anchorterminal.com/compare/nace-drex-vs-scaledown.md)
- [Drex 1.5 vs Vela 2.0](https://www.anchorterminal.com/compare/nace-drex-vs-vela.md)
- [OpenAI Decisions API vs ScaleDown](https://www.anchorterminal.com/compare/openai-decisions-api-vs-scaledown.md)
- [OpenAI Decisions API vs Vela 2.0](https://www.anchorterminal.com/compare/openai-decisions-api-vs-vela.md)
- [pplx-decider vs ScaleDown](https://www.anchorterminal.com/compare/pplx-decider-vs-scaledown.md)
- [pplx-decider vs Vela 2.0](https://www.anchorterminal.com/compare/pplx-decider-vs-vela.md)
- [ScaleDown vs Strands Decider 2B](https://www.anchorterminal.com/compare/scaledown-vs-strands-decider.md)
- [ScaleDown vs Jev](https://www.anchorterminal.com/compare/scaledown-vs-typesafe-jev.md)
- [Strands Decider 2B vs Vela 2.0](https://www.anchorterminal.com/compare/strands-decider-vs-vela.md)
- [Jev vs Vela 2.0](https://www.anchorterminal.com/compare/typesafe-jev-vs-vela.md)