# pplx-decider vs ScaleDown

> pplx-decider scores 62.9 (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/pplx-decider-vs-scaledown
- Markdown: https://www.anchorterminal.com/compare/pplx-decider-vs-scaledown.md (~2,700 tokens)
- Slim: https://www.anchorterminal.com/compare/pplx-decider-vs-scaledown.min.md (~580 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/pplx-decider-vs-scaledown.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: 2026-10-15

pplx-decider scores 62.9 (B) on agent readiness against ScaleDown's 48.6 (D), and leads in 4 of 7 scored categories. ScaleDown leads on payments & pricing. Both do decision models.

- pplx-decider: grade B, 62.9/100, rank #448 of 1094. Markdown https://www.anchorterminal.com/tools/pplx-decider.md · JSON https://www.anchorterminal.com/api/v1/tools/pplx-decider.json
- ScaleDown: grade D, 48.6/100, rank #880 of 1094. Markdown https://www.anchorterminal.com/tools/scaledown.md · JSON https://www.anchorterminal.com/api/v1/tools/scaledown.json
- Best decision models for AI agents: https://www.anchorterminal.com/best/decision-models/index.md
- All 136 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 125 documents comparisons: https://www.anchorterminal.com/compare/document-extraction/index.md

## Which one, for what

### pplx-decider (B)

Good for: High-volume classification, routing and rubric scoring over text and images where a team wants a low hosted price and the option to run the same weights itself.

Ahead on:
- Reliability, 61 against 20
- Schema & documentation, 90 against 69
- Security & auth, 61 against 48
- Maintenance & community, 62 against 56

Watch for: The Decisions API was released in October 2026, so its incident record is days long, and Perplexity's FAQ says it gives no uptime guarantee

### 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:
- Payments & pricing, 40 against 25

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

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


## Score by category

| Category | Weight | pplx-decider | ScaleDown | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 61 | 20 | pplx-decider +41 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 90 | 69 | pplx-decider +21 |
| Agent ergonomics | 13% (16.2 this run) | 76 | 76 | even |
| Security & auth | 14% (17.5 this run) | 61 | 48 | pplx-decider +13 |
| Payments & pricing | 10% (12.5 this run) | 25 | 40 | ScaleDown +15 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 62 | 56 | pplx-decider +6 |
| Transparency & trust | 7% (8.8 this run) | 52 | 54 | ScaleDown +2 |
| Negative events | ≤15 | 0 | -2 | |
| **Total** | | **62.9 · B** | **48.6 · D** | |

## Facts side by side

| Fact | pplx-decider | ScaleDown |
| --- | --- | --- |
| Kind | Model API | Model API |
| Vendor | Perplexity | Carbon ScaleDown, Inc. |
| Hosted endpoint | `https://api.perplexity.ai/v1/decisions` | `https://api.scaledown.xyz` |
| Transports | HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Pay per use | Pay per use |
| Price for decision models | free | not published |
| x402 | no | no |
| Licence | Apache-2.0 for the published weights. The hosted Decisions API is a proprietary service | Proprietary hosted models under ScaleDown's Terms of Service. The langchain-scaledown integration is MIT |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-10-05 | 2026-10-14 |
| Terms last updated | couldn't be read | couldn't be read |
| Privacy policy last updated | couldn't be read | couldn't be read |
| Customer content may train models | couldn't be read | couldn't be read |
| Terms restrict automated access | couldn't be read | couldn't be read |
| Terms restrict benchmarking | couldn't be read | couldn't be read |
| Terms or service can change without notice | couldn't be read | couldn't be read |
| Arbitration or class-action waiver | couldn't be read | couldn't be read |
| Popularity | none | 0 stars |

## Verdicts

**pplx-decider.** The hosted Decisions API has an OpenAPI description, typed questions, documented limits and a published price of $0.02 per million input tokens, and the v1.1 weights are public under Apache-2.0. The API is days old, the official Python SDK has no method for it, and the governing terms and privacy notice could not be read on 9 October 2026.

**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.

## Before you call either

### pplx-decider

1. Send `Authorization: Bearer`. A key in `x-api-key` returns 401 on this endpoint.
2. Set `model` on every request. A missing or unknown model returns 400, and the guide shows a `-latest` name rejected.
3. Resize images to 2,048 tiles of 32 by 32 pixels or fewer before sending. Larger images end in a 504 after about a minute.
4. Check the HTTP status before parsing an error. 404 and 405 have empty bodies, 504 can be HTML, and `error.code` changes type.
5. For the weights, use the repository's `autojev` code. The card says default causal inference does not reproduce the evaluated setup.

### 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

## Questions

### Which is better for AI agents, pplx-decider or ScaleDown?

pplx-decider scores 62.9 (B) on agent readiness against ScaleDown's 48.6 (D), and leads in 4 of 7 scored categories. ScaleDown leads on payments & pricing.

### Do pplx-decider and ScaleDown need an API key?

Both need an API key.

### Can an agent call pplx-decider and ScaleDown without installing anything?

Yes. pplx-decider has a hosted endpoint at https://api.perplexity.ai/v1/decisions and ScaleDown at https://api.scaledown.xyz.


## For agents

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

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