Head to head · Decision models · October 2026 research run

Liquid d1 vs pplx-decider

pplx-decider scores 62.9 (B) on agent readiness against Liquid d1's 43.5 (E), and leads in 5 of 7 scored categories. Both do decision models.

Best decision models for AI agents · All 66 decisions comparisons

Which one, for what

Liquid d1 E

Good for Classification, routing, yes or no gates and rubric scoring over text and images at a low per-token price, or on your own hardware with d1-3B where data can't leave.

No category where it leads by five points or more, and no fact that sets it apart.

Watch for

The terms of 30 September 2026 allow Liquid to train on API content, with no opt-out or zero-retention option found

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 21
  • Schema & documentation, 90 against 59
  • Agent ergonomics, 76 against 63
  • Security & auth, 61 against 35

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

Score by category

CategoryWeight this runLiquid d1pplx-deciderEdge
Reliability16%202161pplx-decider +40
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.25990pplx-decider +31
Agent ergonomics13%16.26376pplx-decider +13
Security & auth14%17.53561pplx-decider +26
Payments & pricing10%12.52725Liquid d1 +2
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.86062pplx-decider +2
Transparency & trust7%8.85452Liquid d1 +2
Negative events≤1500
Total43.5 · E62.9 · B

Facts side by side

FactLiquid d1pplx-decider
KindModel APIModel API
VendorLiquid AIPerplexity
Hosted endpointhttps://api.liquid.ai/decisions/v1/systemonehttps://api.perplexity.ai/v1/decisions
TransportsHTTPHTTP
AuthAPI keyAPI key
PricingFreemiumPay per use
Price for decision modelsnot publishedfree
x402nono
LicenceThe hosted d1 model is proprietary under Liquid AI's terms of service. The d1-3B and d1-omni-600M weights and model code are under the LFM Open Licence v1.0, which is based on Apache-2.0 and conditions commercial use on annual revenue under $10 million. Training code and data aren't publishedApache-2.0 for the published weights. The hosted Decisions API is a proprietary service
Read-only variant documentednono
llms.txtyesyes
Last release2026-10-072026-10-05
Terms last updated2026-09-30couldn't be read
Privacy policy last updated2026-09-30couldn't be read
Customer content may train modelsyescouldn't be read
Terms restrict automated accessnot found in the textcouldn't be read
Terms restrict benchmarkingnot found in the textcouldn't be read
Terms or service can change without noticenot found in the textcouldn't be read
Arbitration or class-action waivernot found in the textcouldn't be read

Verdicts

Liquid d1

The hosted API costs $0.04 per million input tokens and takes TypeSafe's System One request, and the d1-3B weights run locally through Transformers or llama.cpp. Liquid's terms allow it to train on API content, and no status page, rate limits or error reference were found. The family launched between 22 September and 7 October 2026.

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.

Before you call either

Liquid d1

  1. POST to https://api.liquid.ai/decisions/v1/systemone with a liquid_ key as a Bearer header. This is not a chat-completions endpoint
  2. Use d1 for images. d1:free is text-only and answers that it does not accept images
  3. Send images as Base64 data URLs in images, at most 8, with the whole JSON body under 4.5 MB. Remote image URLs are refused
  4. Budget tokens per question. Each question is billed as its own prompt, with its text and every image counted again
  5. Don't send confidential content to the hosted API, since the terms allow training on it. Run d1-3B locally for that data

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.

Questions

Which is better for AI agents, Liquid d1 or pplx-decider?

pplx-decider scores 62.9 (B) on agent readiness against Liquid d1's 43.5 (E), and leads in 5 of 7 scored categories.

Do Liquid d1 and pplx-decider need an API key?

Both need an API key.

Can an agent call Liquid d1 and pplx-decider without installing anything?

Yes. Liquid d1 has a hosted endpoint at https://api.liquid.ai/decisions/v1/systemone and pplx-decider at https://api.perplexity.ai/v1/decisions.

Other comparisons with Liquid d1 or pplx-decider

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