Baseten
•
Joey 1
•
Released 
October 2026

Baseten
Joey 1

A 2B decision model that returns calibrated probabilities in about 20 ms, built for high-volume routing and classification.

Modality:
Text
model ID
baseten/joey-1

Output Speed *

N/A
tok/s

Intelligence Index *

N/A
/ 100

Context Window *

16384
tokens

Input price

0.06
Anytoken

Output price

0
Anytoken
joey-1: A 2B Decision Model Built for 20 ms Routing and Classification joey-1 is a 2B-parameter decision model from Baseten's research lab, Base Labs, post-trained from Qwen3.5-2B. It doesn't generate text. It takes a state and typed questions and returns a calibrated probability for every option in one forward pass. It is the smallest and fastest model in the Base Labs family, below elephant-1 (9B) and mammoth-1 (27B). It fits high-volume routing, classification and guardrail checks, where decision latency is added to every response. Access joey-1 through AnyAPI.ai

Performance

Why joey-1 Answers in 20 ms: No Text Generation, One Forward Pass

joey-1 does one job: it returns a label and calibrated confidence in a single forward pass instead of generating text. Baseten reports a 20 ms median end-to-end latency on an average 2,000-token request, about 2.5x faster than elephant-1 at 49 ms. These are provider-reported figures, but the design explains them: there is no decoding loop and no output parsing. In production, joey-1 fits as a first-pass gate in front of slower models, with uncertain cases escalated.

Benchmarks

joey-1 on the Jev Decision Index: Best Under 4B, Behind Its Siblings

On the public split of the Jev Decision Index 0.4, a Hugging Face community leaderboard, joey-1 scores 63.30. That ranks 37th of 230 models and first among models under 4B. The scores come from Baseten's model card, not an independent re-run. elephant-1 scores 72.24 on the same split, and joey-1 trails it in every area. On Base Labs' own replica of the Artificial Analysis Decision Index, joey-1 scores 62.9 against 65.9 for mammoth-1. Validate on your own labeled data.

Output Speed

*
N/A
tok/s

Intelligence Index

*
N/A
/ 100

MMLU *

Broad world knowledge and problem-solving
0
%

GPQA *

PhD-level scientific reasoning across physics, biology, chemistry.
0
%

HLE *

Adherence to multi-step structured instructions.
0
%

LiveCodeBench *

Tool-calling reliability in long agentic loops.
0
%

Technical Specifications

What the model supports

joey-1 accepts text, optionally with images, and returns probabilities rather than prose. It supports three question types: yes/no, choice among named options, and ordered scoring. Model APIs offer a 16,384-token context window, while dedicated deployments unlock 262k. Context is the constraint to plan around: long documents or many images must be truncated or chunked on the shared API. Baseten publishes no maximum-output figure, since responses are structured probabilities.
Verified Specifications — 
Joey 1
*
Input modalities
Text
output modalities
Text
Context window
16384
 tokens
Maximum output tokens
14745
Reasoning
No
Knowledge cutoff
October 2026
Pricing (standard)
0.06
 AnyTokens in
 / 
0
 AnyTokens out

Comparison

joey-1 or elephant-1: Speed and Cost Versus Decision Accuracy

joey-1 and elephant-1 are the 2B and 9B members of Baseten's Base Labs decision-model family. Both are trained on the same data mixture and share the same System One API, so Baseten describes switching between them as a one-line change. The practical decision is a trade-off. Baseten reports 20 ms P50 for joey-1 versus 49 ms for elephant-1, and joey-1 is priced lower. On the Jev Decision Index 0.4 public split, however, elephant-1 scores 72.24 against joey-1's 63.30.

Dimension
Joey 1
Elephant 1
Context window *
16384
tokens
16384
tokens
Output speed *
N/A
tok/s
N/A
tok/s
Intelligence Index *
N/A
N/A
Input pricing
0.06
AnyToken
0.21
AnyToken
Output pricing
0
AnyToken
0
AnyToken
Knowledge cutoff *
October 2026
October 2026

Choose joey-1 when decision volume is high, latency is added to every user-facing response, and a first-pass answer with escalation for uncertain cases is acceptable. Choose elephant-1 when decisions carry more risk, need broader general knowledge, or when joey-1's accuracy on your labeled data falls short. Baseten positions elephant-1 as the balanced default. A common pattern is joey-1 first, with elephant-1 handling low-confidence cases.

Limitations & Trade-offs

Where Joey 1 falls short

1
Lower accuracy than its siblings. joey-1 scores 63.30 on the Jev Decision Index 0.4 public split, while elephant-1 scores 72.24. The model card says joey-1 trails elephant-1 in every evaluated area. It leads only among models under 4B, not overall. For high-stakes approvals, compliance decisions or ambiguous inputs, use elephant-1 or mammoth-1, or use joey-1 only as a first pass.
2
No free-form text. joey-1 returns calibrated probabilities for typed questions and does not generate prose, explanations or chat replies. Chat-completions SDKs and code written for them will not carry over unchanged, because the request is a state plus typed questions. Workloads that need rationale, drafting or open-ended Q&A require a generative model alongside it.
3
16K context on the shared API. Model APIs support 16,384 tokens, and the model was trained at that maximum sequence length. The 262k window needs a dedicated deployment. Long contracts, large document sets or image-heavy states must be chunked or truncated on Model APIs, which can hurt decision quality. For long-input decisions, plan for a dedicated deployment or a different model.
4
Mostly self-reported evidence. The Jev scores, the Artificial Analysis replica result and the 20 ms latency all come from Baseten or Base Labs. Baseten says the internal tests behind its strongest-under-3B claim are still to come. The model card is also cautious about generalizing, and Baseten recommends larger siblings for tasks needing broader general knowledge. Test joey-1 on your own labeled data before committing.

Best-Fit Workloads

Where this model earns its place

01

Support ticket triage and routing

‍
Baseten lists ticket triage and routing as a core decision-model use case. joey-1 can answer several typed questions about one message in a single request, such as team, urgency and refund eligibility, with the questions sharing an input prefill. A 20 ms reported median latency and low per-token cost suit very high ticket volumes. Tickets that come back with low confidence can be escalated to elephant-1 or mammoth-1.

02

Guardrails and abuse screening

‍
Baseten cites spam and phishing detection and prompt-guardrail or jailbreak checks as decision-model use cases. A guardrail sits in front of every request, so its latency adds to every response. That is where joey-1's speed matters most. Training included a safety-and-abstention data share and a trained 'I don't know' option, which helps surface uncertain inputs. Borderline cases still warrant a larger model or human review.

03

First-pass gate in LLM cascades

‍
Baseten recommends joey-1 as a first-line model, with elephant-1 or mammoth-1 as the escalation path when it is uncertain. It also lists routing between small and frontier LLMs as a use case. Because joey-1 returns a probability, you can set a confidence threshold: act on confident answers and pass the rest on. This keeps expensive generative calls for requests that need them.

04

Rubric scoring and yes/no checks

‍
joey-1 supports ordered scoring levels as well as yes/no and multiple-choice questions, so it can score content against a rubric and return typed answers your code can use directly. It suits bulk quality checks and content classification. It does not explain a score, and it is less accurate than its larger siblings on harder judging tasks.

Pricing in anytokens via AnyAPI
Input
0.06
₳
Output
0
₳
Cache write
—
₳
Cache read
—
₳

Integration

Access Joey 1 via AnyAPI.ai

Access Joey 1 through AnyAPI.ai using a unified API built for multi-model AI applications. Integrate Joey 1 without maintaining a separate provider-specific connection, and keep the flexibility to test, switch, or combine models as your application requirements evolve.

01

One API integration

Access Joey 1 and other AI models through the same API workflow instead of maintaining separate integrations for every provider.

02

Easy model switching

Test Joey 1 against alternative models or switch models as your performance, capability, or cost requirements change without rebuilding your application around another provider API.

03

Flexible for production

Use Joey 1 from experimentation through production while keeping your AI stack flexible as workloads, traffic, and model requirements evolve.

04

Multi-model applications

Use Joey 1 for the workloads where it performs best and combine it with other models for tasks that require different capabilities, performance, or efficiency.

Frequently Asked Questions

Answers to common questions about integrating and using this AI model via AnyAPI.ai

joey-1 is a 2B-parameter decision model from Baseten's Base Labs, released October 29, 2026 and post-trained from Qwen3.5-2B. Given a state and typed questions, it returns a calibrated probability for every answer option in one forward pass, without generating text. It targets routing, classification, yes/no checks and rubric scoring.

On Baseten Model APIs, joey-1 supports a 16,384-token context window. Baseten says dedicated deployments unlock the full 262k context window. Baseten publishes no maximum-output-token figure, because joey-1 returns structured probabilities rather than generated text.

No. joey-1 returns calibrated probabilities for predefined options and does not produce free-form text. Its endpoint is a decision-style System One request with a state and typed questions, not an OpenAI-style chat-completions call. For drafting, summarizing or explanations, use a generative model and keep joey-1 as the routing or classification layer.

elephant-1 is more accurate, and joey-1 is faster. On the Jev Decision Index 0.4 public split, joey-1 scores 63.30 and elephant-1 scores 72.24. Baseten reports a 20 ms P50 latency for joey-1 versus 49 ms for elephant-1. All of these figures are self-reported by Baseten, so test on your own data.

Yes to both. joey-1 accepts text input, optionally with images, and returns structured decisions. Its weights are published on Hugging Face under the MIT license, so you can self-host it. You can also use it through Baseten Model APIs, which have zero data retention on by default.

* Benchmark data source: Artificial Analysis artificialanalysis.ai