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SDKs & APIs

Last updated January 21, 2026

AI Gateway provides drop-in compatible APIs that let you switch by changing a base URL. No code rewrites required. Use the same SDKs and tools you already know, with access to 200+ models from every major provider.

Quick start

Point your existing SDK to the gateway:

npm i ai @ai-sdk/openai
import { generateText } from 'ai';
 
const { text } = await generateText({
  model: 'anthropic/claude-sonnet-4.6',
  prompt: 'Hello!',
});
import OpenAI from 'openai';
 
const client = new OpenAI({
  apiKey: process.env.AI_GATEWAY_API_KEY,
  baseURL: 'https://ai-gateway.vercel.sh/v1',
});
 
const response = await client.chat.completions.create({
  model: 'anthropic/claude-sonnet-4.6',
  messages: [{ role: 'user', content: 'Hello!' }],
});
import OpenAI from 'openai';
 
const client = new OpenAI({
  apiKey: process.env.AI_GATEWAY_API_KEY,
  baseURL: 'https://ai-gateway.vercel.sh/v1',
});
 
const response = await client.responses.create({
  model: 'anthropic/claude-sonnet-4.6',
  input: 'Hello!',
});
import Anthropic from '@anthropic-ai/sdk';
 
const client = new Anthropic({
  apiKey: process.env.AI_GATEWAY_API_KEY,
  baseURL: 'https://ai-gateway.vercel.sh',
});
 
const message = await client.messages.create({
  model: 'anthropic/claude-sonnet-4.6',
  max_tokens: 1024,
  messages: [{ role: 'user', content: 'Hello!' }],
});
import OpenAI from 'openai';
 
const client = new OpenAI({
  apiKey: process.env.AI_GATEWAY_API_KEY,
  baseURL: 'https://ai-gateway.vercel.sh/openresponses/v1',
});
 
const response = await client.responses.create({
  model: 'anthropic/claude-sonnet-4.6',
  input: 'Hello!',
});

Why use these APIs?

  • No vendor lock-in: Switch between Claude, GPT, Gemini, and other models without changing your code
  • Unified billing: One invoice for all providers instead of managing multiple accounts
  • Built-in fallbacks: Automatic retry with alternative providers if one fails
  • Streaming support: Real-time responses with SSE across all compatible endpoints
  • Full feature parity: Tool calling, structured outputs, vision, and embeddings work exactly as documented

Available APIs

APIBest forDocumentation
AI SDK (recommended)Normalizes provider differences, works with AI Gateway automaticallyStreaming, Structured outputs, Tools
OpenAI Responses APIOpenAI Responses API usersStreaming, Tools, Structured output
OpenAI Chat Completions APIExisting OpenAI integrations, broad language supportChat, Tools, Embeddings
Anthropic Messages APIClaude Code, Anthropic SDK usersMessages, Tools, Files
OpenResponsesNew projects, provider-agnostic designStreaming, Tools, Vision
PythonPython developersAsync, Streaming, Frameworks

Choosing an API

  • New project? Use AI SDK. It handles provider differences for you and supports streaming, structured outputs, tool calling, and reasoning across all providers.
  • Using the OpenAI SDK? The OpenAI Responses API and Chat Completions API both work by changing your base URL.
  • Using Claude Code or the Anthropic SDK? Use the Anthropic Messages API for native feature support.
  • Want a provider-agnostic REST API? Use OpenResponses.

Next steps

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