Developer Platform

Build with every model.
From one platform.

One OpenAI-compatible API, typed SDKs in three languages, an agent framework, local devtools, and an MCP server — backed by 400+ models across 70+ providers with automatic fallback.

Get an API key Read the docs

Everything you need to ship

Six products, one API key. Start with a single request and grow into a production agent without changing providers.

API

One OpenAI-compatible endpoint for 400+ models across 70+ providers, with automatic fallback when a provider fails.

https://openrouter.ai/api/v1

Client SDKs

The same typed client in TypeScript, Python, and Go — streaming, tools, and structured output behave identically in every language.

npm i @openrouter/sdk

Agent SDK

Type-safe tools, multi-turn loops, streaming, and stop conditions. Build production agents that route across every provider.

npm i @openrouter/agent

DevTools

Capture SDK telemetry in development and replay every request, token count, and error in a local web viewer.

npm install -g @openrouter/cli

MCP Server

Give any Model Context Protocol client — Claude Code, Cursor, or your own — access to all 400+ models.

https://mcp.openrouter.ai/mcp

Cookbook

Working recipes for agent harnesses, human-in-the-loop tools, evals, cost control, and image generation.

A few lines to production

Swap the model string to change providers. Nothing else about your code has to change.

import { OpenRouter } from '@openrouter/sdk';

const client = new OpenRouter({
  apiKey: process.env.OPENROUTER_API_KEY,
});

const response = await client.chat.send({
  model: 'anthropic/claude-sonnet-4',
  messages: [
    { role: 'user', content: 'Explain quantum computing in simple terms.' },
  ],
});

console.log(response.choices[0].message.content);

from openrouter import OpenRouter
import os

with OpenRouter(
    api_key=os.getenv("OPENROUTER_API_KEY")
) as client:
    response = client.chat.send(
        model="anthropic/claude-sonnet-4",
        messages=[
            {"role": "user", "content": "Explain quantum computing in simple terms."}
        ]
    )

    print(response.choices[0].message.content)

import { OpenRouter } from '@openrouter/sdk';

const client = new OpenRouter();

const stream = await client.chat.send({
  model: 'openai/gpt-4o',
  messages: [{ role: 'user', content: 'Write a short story about a robot.' }],
  stream: true,
});

for await (const chunk of stream) {
  process.stdout.write(chunk.choices[0]?.delta?.content ?? '');
}

from openrouter import OpenRouter
import os

with OpenRouter(
    api_key=os.getenv("OPENROUTER_API_KEY")
) as client:
    stream = client.chat.send(
        model="openai/gpt-4o",
        messages=[
            {"role": "user", "content": "Write a short story about a robot."}
        ],
        stream=True
    )

    for event in stream:
        content = event.choices[0].delta.content if event.choices else None
        if content:
            print(content, end="", flush=True)

// Multi-turn tool loops live in the Agent SDK: npm i @openrouter/agent
import { OpenRouter, tool, stepCountIs } from '@openrouter/agent';
import { z } from 'zod';

const openrouter = new OpenRouter();

const weatherTool = tool({
  name: 'get_weather',
  description: 'Get the weather for a location',
  inputSchema: z.object({
    location: z.string(),
  }),
  execute: async ({ location }) => {
    return { temperature: 72, condition: 'sunny' };
  },
});

const result = openrouter.callModel({
  model: 'openai/gpt-4o',
  input: 'What should I wear in San Francisco today?',
  tools: [weatherTool],
  stopWhen: stepCountIs(5),
});

console.log(await result.getText());

# The Client SDK returns tool calls for you to dispatch yourself.
from openrouter import OpenRouter
import os

with OpenRouter(
    api_key=os.getenv("OPENROUTER_API_KEY")
) as client:
    response = client.chat.send(
        model="openai/gpt-4o",
        messages=[
            {"role": "user", "content": "What should I wear in San Francisco today?"}
        ],
        tools=[{
            "type": "function",
            "function": {
                "name": "get_weather",
                "description": "Get the weather for a location",
                "parameters": {
                    "type": "object",
                    "properties": {"location": {"type": "string"}},
                    "required": ["location"],
                },
            },
        }]
    )

    print(response.choices[0].message.tool_calls)

Live in three steps

Most teams are through their first successful request in under five minutes.

1
Get an API key
Create a key from your dashboard. No subscription and no card required to start.
2
Point your client at OpenRouter
Already using the OpenAI SDK? Change the base URL and your key. Everything else stays put.
3
Pick any model
Use an author/slug string. Add fallbacks so a provider outage never becomes your outage.
Read the full quickstart

Your first request

curl https://openrouter.ai/api/v1/chat/completions \
  -H "Authorization: Bearer $OPENROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "models": [
      "anthropic/claude-sonnet-4",
      "openai/gpt-4o",
      "google/gemini-2.5-pro"
    ],
    "messages": [
      { "role": "user", "content": "Hello!" }
    ]
  }'

Start building today

Free to get started. No subscription, no card required.

Get an API key Read the docs

Developer Platform

Build with every model.
From one platform.

One OpenAI-compatible API, typed SDKs in three languages, an agent framework, local devtools, and an MCP server — backed by 400+ models across 70+ providers with automatic fallback.

Get an API key Read the docs

Everything you need to ship

Six products, one API key. Start with a single request and grow into a production agent without changing providers.

A few lines to production

Swap the model string to change providers. Nothing else about your code has to change.

import { OpenRouter } from '@openrouter/sdk';

const client = new OpenRouter({
  apiKey: process.env.OPENROUTER_API_KEY,
});

const response = await client.chat.send({
  model: 'anthropic/claude-sonnet-4',
  messages: [
    { role: 'user', content: 'Explain quantum computing in simple terms.' },
  ],
});

console.log(response.choices[0].message.content);

from openrouter import OpenRouter
import os

with OpenRouter(
    api_key=os.getenv("OPENROUTER_API_KEY")
) as client:
    response = client.chat.send(
        model="anthropic/claude-sonnet-4",
        messages=[
            {"role": "user", "content": "Explain quantum computing in simple terms."}
        ]
    )

    print(response.choices[0].message.content)

import { OpenRouter } from '@openrouter/sdk';

const client = new OpenRouter();

const stream = await client.chat.send({
  model: 'openai/gpt-4o',
  messages: [{ role: 'user', content: 'Write a short story about a robot.' }],
  stream: true,
});

for await (const chunk of stream) {
  process.stdout.write(chunk.choices[0]?.delta?.content ?? '');
}

from openrouter import OpenRouter
import os

with OpenRouter(
    api_key=os.getenv("OPENROUTER_API_KEY")
) as client:
    stream = client.chat.send(
        model="openai/gpt-4o",
        messages=[
            {"role": "user", "content": "Write a short story about a robot."}
        ],
        stream=True
    )

    for event in stream:
        content = event.choices[0].delta.content if event.choices else None
        if content:
            print(content, end="", flush=True)

// Multi-turn tool loops live in the Agent SDK: npm i @openrouter/agent
import { OpenRouter, tool, stepCountIs } from '@openrouter/agent';
import { z } from 'zod';

const openrouter = new OpenRouter();

const weatherTool = tool({
  name: 'get_weather',
  description: 'Get the weather for a location',
  inputSchema: z.object({
    location: z.string(),
  }),
  execute: async ({ location }) => {
    return { temperature: 72, condition: 'sunny' };
  },
});

const result = openrouter.callModel({
  model: 'openai/gpt-4o',
  input: 'What should I wear in San Francisco today?',
  tools: [weatherTool],
  stopWhen: stepCountIs(5),
});

console.log(await result.getText());

# The Client SDK returns tool calls for you to dispatch yourself.
from openrouter import OpenRouter
import os

with OpenRouter(
    api_key=os.getenv("OPENROUTER_API_KEY")
) as client:
    response = client.chat.send(
        model="openai/gpt-4o",
        messages=[
            {"role": "user", "content": "What should I wear in San Francisco today?"}
        ],
        tools=[{
            "type": "function",
            "function": {
                "name": "get_weather",
                "description": "Get the weather for a location",
                "parameters": {
                    "type": "object",
                    "properties": {"location": {"type": "string"}},
                    "required": ["location"],
                },
            },
        }]
    )

    print(response.choices[0].message.tool_calls)

Live in three steps

Most teams are through their first successful request in under five minutes.

1
Get an API key
Create a key from your dashboard. No subscription and no card required to start.
2
Point your client at OpenRouter
Already using the OpenAI SDK? Change the base URL and your key. Everything else stays put.
3
Pick any model
Use an author/slug string. Add fallbacks so a provider outage never becomes your outage.
Read the full quickstart

Your first request

curl https://openrouter.ai/api/v1/chat/completions \
  -H "Authorization: Bearer $OPENROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "models": [
      "anthropic/claude-sonnet-4",
      "openai/gpt-4o",
      "google/gemini-2.5-pro"
    ],
    "messages": [
      { "role": "user", "content": "Hello!" }
    ]
  }'

Start building today

Free to get started. No subscription, no card required.

Get an API key Read the docs

Build with every model. From one platform.

Everything you need to ship

A few lines to production

Live in three steps

Get an API key

Point your client at OpenRouter

Pick any model

Start building today

Build with every model. From one platform.

Everything you need to ship

A few lines to production

Live in three steps

Get an API key

Point your client at OpenRouter

Pick any model

Start building today

Build with every model.
From one platform.

Build with every model.
From one platform.