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Step 5 Preview now available on AI Gateway

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Step 5 Preview, StepFun's flagship model, is now available on AI Gateway. It's built for agentic coding, professional knowledge work, and financial analysis, from building apps and debugging code to research and analytical reports.

Step 5 Preview supports text and image input with a 1M-token context window, allowing you to work with large codebases, a stack of documents, or screenshots and charts in a single request.

Use stepfun/step-5-preview as the model name:

import { streamText } from 'ai';


const result = streamText({
  model: 'stepfun/step-5-preview',
  prompt: 'Plan a dashboard for analyzing quarterly financial results.',
});


for await (const text of result.textStream) {
  process.stdout.write(text);
}
View model details

For other coding agents such as Claude Code, Codex, Cursor, and more, install the latest Vercel CLI and run setup:

npm i -g vercel@latest
vercel ai-gateway setup

Then select stepfun/step-5-preview in the agent. See the coding agents guide for details.

Try Step 5 Preview in the model playground.

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 custom reporting, Zero Data Retention support, budgets for API keys, routing rules, and more.

AI Gateway reflects provider pricing with no markup and does not charge a platform fee on inference, including on Bring Your Own Key (BYOK) requests.

You can view all language models available on AI Gateway.