GPT-5.3 Chat (GPT 5.3 Instant) is now available on AI Gateway.

This update focuses on tone, relevance, and conversational flow for more accurate answers, better-contextualized web results, and fewer unnecessary refusals and caveats. It also reduces hallucination rates and produces smoother and more direct responses.

To use this model, set model to openai/gpt-5.3-chat in the AI SDK.

import { streamText } from 'ai';
const result = streamText({
  model: 'openai/gpt-5.3-chat',
  prompt: 'Best restaurants in SF for a birthday dinner.',
});

AI Gateway provides a unified API for calling models, tracking usage and cost, and configuring retries, failover, and performance optimizations for higher-than-provider uptime. It includes built-in observability, Bring Your Own Key support, and intelligent provider routing with automatic retries.

Learn more about AI Gateway, view the AI Gateway model leaderboard or try it in our model playground.