Google Launches Gemini Decisions API for Multimodal Decisions

Google has launched the Gemini Decisions API, a new endpoint for fast, closed-set decisions powered by the Gemini Decision 1 model (gemini-decision-1), available through the Gemini API in Google AI Studio.

Product Details

The Decisions API provides purpose-built primitives for bounded choices such as tool selection, policy checks, model routing, and context grading. Users can pass one multimodal input across text, images, audio, video, and PDFs (up to 256K tokens) along with up to 1,000 independent questions. Rather than generating answer text token by token, Gemini Decision 1 scores candidate options in a single forward pass, returning probabilities and confidence scores in 150-250 ms end-to-end latency at $0.10 per 1M input tokens with zero output tokens billed.

Google says Gemini Decision 1 leads across a benchmark suite spanning agent routing, reasoning, ranking, and multimodal understanding, with the lowest calibration error. The model keeps median latency at 50-100 ms of model compute (150-250 ms end-to-end), across multimodal inputs and contexts up to 16K tokens, remaining nearly flat from 1 to 100 questions per request. With zero output tokens billed, Google says Gemini Decision 1 with the Decisions API is nearly 5x cheaper across the shared benchmark suite than Gemini 3.5 Flash-Lite with the Interactions API.

Decision Types

The API supports three decision types in one pass:

• noul (Yes/No): Estimates the probability that a yes/no condition holds, with optional true and false description criteria.
• choice (Multiple Choice): Selects from 2 to 255 choices, returning the winner and normalized probabilities for every candidate.
• score (Ordered Rubric): Grades inputs across an ordered rubric (starting at 0), returning a continuous weighted score and per-level probabilities.

Every answer includes a confidence score (from 0 to 1) so code can route ambiguous cases to a fallback or human reviewer.

Use Cases

Teams across Google are using the Decisions API as a low-latency control plane:

• Gemini Notebook uses the Decisions API as a real-time router to instantly direct incoming queries to the optimal model tier and thinking level for each request. The Decisions API classifies intent in milliseconds to serve everyday queries with up to 40% lower latency while reserving deep reasoning models for complex tasks.
• Stitch uses the Decisions API to generate playable wireframes of a product flow in seconds and to apply edits made by voice or tap almost instantly.
• CC from Google Labs uses the Decisions API to pick the right emoji reaction from a palette of more than 200 options in a fraction of a second.
• Google Search uses the Decision API to detect adversarial behavior and content against adversarial evals with high efficacy within the latency envelope.

Pricing and Availability

Gemini Decision 1 is priced at $0.10 per 1M input tokens and $0 for output tokens, with an API no-cost tier available in Google AI Studio for prototyping. The shared input is billed once per request no matter how many questions are evaluated; each question adds only its own instruction and criteria tokens. There are no output-token charges, variable thinking-token bills, or separate audio transcription and OCR costs.

Developers can start building by grabbing an API key in Google AI Studio and following the Python, JavaScript, and REST guides in the Decisions API documentation. Ecosystem integrations are rolling out across OpenRouter, LangChain, Vercel, LiteLLM, Pydantic AI, Pipecat, LiveKit, and OpenCode alongside the google-genai SDKs, with support coming soon to Gemini in Google Cloud.

Why it matters

The Gemini Decisions API offers a low-latency, cost-effective alternative to token-by-token generation for bounded multimodal decisions, allowing developers to route ambiguous cases to human reviewers using confidence scores.

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Sources

• blog.google: Gemini Decisions API: Fast multimodal decisions

This article was drafted with AI assistance and checked against the sources above. Company claims are reported as claims. Cover image is AI-generated.