Connect VoltAgent to the AI Gateway

Send requests from your VoltAgent agents through the Logfire AI Gateway.

VoltAgent is a TypeScript framework for building AI agents with tool use and its own observability features. The example creates an OpenAI-compatible provider that uses the gateway key and route.

Before you start

• Complete the AI Gateway prerequisites, including setting LOGFIRE_GATEWAY_API_KEY in your terminal.
• Use an existing VoltAgent project with the packages imported below installed.

Model data passes through Logfire

This configuration sends prompts, tool inputs, and model responses through the Logfire AI Gateway and the selected model provider. If gateway telemetry is enabled, Logfire stores the conversation content in your selected project. Calls to built-in providers count toward your gateway spend.

Configure VoltAgent

Set apiKey to your gateway key and baseURL to the OpenAI-compatible gateway route. Copy the route and a supported model name from the Gateway Connect tab.

voltagent-gateway.mts

import { createOpenAICompatible } from '@ai-sdk/openai-compatible';
import { Agent } from '@voltagent/core';
import { z } from 'zod';

const envSchema = z.object({
  LOGFIRE_GATEWAY_API_KEY: z.string(),
});

const env = envSchema.parse(process.env);

const gateway = createOpenAICompatible({
  name: 'logfire-gateway',
  apiKey: env.LOGFIRE_GATEWAY_API_KEY,
  baseURL: 'https://gateway-us.pydantic.dev/proxy/openai',
});

const agent = new Agent({
  name: 'weather-agent',
  instructions: 'A helpful assistant that answers questions.',
  model: gateway.chatModel('gpt-5.4-mini'),
});

const response = await agent.generateText('What is the weather in London?');

console.log(response.text);

Verify it worked

Run the example from your terminal. It prints the agent’s response. That confirms the client reached the gateway. Organization admins can also open AI Engineering > Gateway > Spending to see usage for the key. If telemetry is enabled, open the selected project’s Live view to inspect the request trace.

Troubleshooting

• The example cannot read LOGFIRE_GATEWAY_API_KEY: set the environment variable in the same terminal where you run the example.
• The request returns an authentication or model error: copy the URL and model name again from the Gateway Connect tab, and confirm that the selected route supports the OpenAI request format.