Description: Learn how to optimize latency with the Priority inference tier in the Interactions API
> [!WARNING] > **Preview:** The Gemini Priority API is in [Preview](https://cloud.google.com/products#product-launch-stages). The Gemini Priority API is a premium inference tier designed for business-critical workloads that require lower latency and the highest reliability at a premium price point. Priority tier traffic is prioritized above standard API and Flex tier traffic. Priority inference is available across the Interactions API endpoints. ## How to use Priority To use the Priority tier, set the `service_tier` field in your request to `priority`. The default tier is standard if the field is omitted. ### Python from google import genai client = genai.Client() interaction = client.interactions.create( model="gemini-3.8-flash", input="Triage this critical customer support ticket immediately.", service_tier='priority' ) print(interaction.output_text) ### JavaScript import { GoogleGenAI } from '@google/genai'; const ai = new GoogleGenAI({}); async function main() { const interaction = await ai.interactions.create({ model: "gemini-3.8-flash", input: "Triage this critical customer support ticket immediately.", service_tier: "priority" }); console.log(interaction.output_text); } await main(); ### Java import com.google.genai.Client; import com.google.genai.gaos.models.interactions.CreateModelInteraction; import com.google.genai.gaos.models.interactions.Interaction; import com.google.genai.gaos.models.interactions.InteractionsInput; import com.google.genai.gaos.models.interactions.Model; import com.google.genai.gaos.models.interactions.ServiceTier; import com.google.genai.gaos.models.operations.CreateInteractionRequestBody; Client client = new Client(); CreateModelInteraction params = CreateModelInteraction.builder() .model(Model.of("gemini-3.8-flash")) .input(InteractionsInput.of("Perform a priority inference task.")) .serviceTier(ServiceTier.PRIORITY) .build(); Interaction interaction = client.interactions.create(CreateInteractionRequestBody.of(params)).interaction().get(); System.out.println(interaction.outputText().orElse("")); ### REST curl -X POST "https://generativelanguage.googleapis.com/v1beta/interactions" \ -H "Content-Type: application/json" \ -H "x-goog-api-key: $GEMINI_API_KEY" \ -d '{ "model": "gemini-3.8-flash", "input": "Triage this critical customer support ticket immediately.", "service_tier": "priority" }' ## How Priority inference works Priority inference routes requests to high-criticality compute queues, offering predictable, fast performance for user-facing applications. Its primary mechanism is a graceful server-side downgrade to standard processing for traffic that exceeds dynamic limits, ensuring application stability instead of failing the request. | Feature | Priority | Standard | Flex | Batch | |---|---|---|---|---| | **Pricing** | 75-100% more than Standard | Full price | 50% discount | 50% discount | | **Latency** | Seconds | Seconds to minutes | Minutes (1--15 min target) | Up to 24 hours | | **Reliability** | High (Non-sheddable) | High / Medium-high | Best-effort (Sheddable) | High (for throughput) | | **Interface** | Synchronous | Synchronous | Synchronous | Asynchronous | ### Key benefits - **Low latency**: Designed for second response times for interactive, user-facing AI tools. - **High reliability**: Traffic is treated with the highest criticality and is strictly non-sheddable. - **Graceful degradation**: Traffic spikes exceeding dynamic limits are automatically downgraded to the Standard tier for processing instead of failing, preventing service outages. - **Low friction** : Uses the same synchronous `create` method as the standard and Flex tiers. ### Use cases Priority processing is ideal for business-critical workflows where performance and reliability are paramount. - **Interactive AI applications**: Customer service chatbots and copilots where users pay a premium and expect fast, consistent responses. - **Real-time decision engines**: Systems requiring highly reliable, low-latency outcomes, such as live ticket triaging or fraud detection. - **Premium customer features**: Developers who need to guarantee higher service level objectives (SLOs) for paying customers. ### Rate limits Priority consumption holds its own rate limits even though consumption is counted towards [overall interactive traffic rate limits](https://aistudio.google.com/rate-limit). The default rate limits for Priority inference are **0.3x standard rate limit for Model / Tier** ### Graceful downgrade logic If Priority limits are exceeded due to congestion, overflow requests are **automatically and gracefully** downgraded to Standard processing instead of failing with a 503 or 429 error. Downgraded requests are billed at the standard rate, not the Priority premium rate. ### Client responsibility - **Response monitoring** : Developers should monitor the `x-gemini-service-tier` header in the API response to detect if requests are being frequently downgraded to `standard`. - **Retries** : Clients must implement retry logic/exponential backoff for standard errors, such as `DEADLINE_EXCEEDED`. ## Pricing Priority inference is priced at 75-100% more than the [standard API](https://ai.google.dev/gemini-api/docs/pricing) and billed per token. ## Supported models The following models support Priority inference: | Model | Priority inference | |---|---| | [Gemini 3.8 Flash](https://ai.google.dev/gemini-api/docs/models/gemini-3.8-flash) | ✔️ | | [Gemini 3.7 Flash](https://ai.google.dev/gemini-api/docs/models/gemini-3.7-flash) | ✔️ | | [Gemini 3.6 Flash](https://ai.google.dev/gemini-api/docs/models/gemini-3.6-flash) | ✔️ | | [Gemini 3.5 Flash-Lite](https://ai.google.dev/gemini-api/docs/models/gemini-3.5-flash-lite) | ✔️ | | [Gemini 3.5 Flash](https://ai.google.dev/gemini-api/docs/models/gemini-3.5-flash) | ✔️ | | [Gemini 3.1 Flash-Lite](https://ai.google.dev/gemini-api/docs/models/gemini-3.1-flash-lite) | ✔️ | | [Gemini 3.1 Pro Preview](https://ai.google.dev/gemini-api/docs/models/gemini-3.1-pro-preview) | ✔️ | | [Gemini 3 Flash Preview](https://ai.google.dev/gemini-api/docs/models/gemini-3-flash-preview) | ✔️ | | [Gemini 2.5 Pro](https://ai.google.dev/gemini-api/docs/models/gemini-2.5-pro) | ✔️ | | [Gemini 2.5 Flash](https://ai.google.dev/gemini-api/docs/models/gemini-2.5-flash) | ✔️ | | [Gemini 2.5 Flash-Lite](https://ai.google.dev/gemini-api/docs/models/gemini-2.5-flash-lite) | ✔️ | ## What's next - [Flex inference](https://ai.google.dev/gemini-api/docs/flex-inference) for cost reduction. - [Tokens](https://ai.google.dev/gemini-api/docs/tokens): Understand tokens.