One API, Multiple LLMs with OpenRouter.ai

LLMs such as Claude 4, GPT-4o, and Llama come from various providers, each having their own billing systems (typically credit-based), separate API keys, and individual setups.

While sticking with one provider like OpenAI or Anthropic might seem easier, it limits your flexibility, like performing A/B tests across different AI models.

Additionally, dependency on a single provider could leave your application vulnerable if the provider experiences downtime/degradation.

They go down, you go down 😜

On the other hand, choosing multiple providers comes with it’s own challenges like:

• Setting up individual accounts with each provider.
• Managing credits independently.
• Generating separate API keys.
• Handling multiple SDK integrations within your application.

OpenRouter.ai solves these challenges by acting as a unified API gateway.

Single API, Multiple LLM models

With OpenRouter, all you need is a single account and one credit management system to seamlessly access multiple models.

Here’s an example:

curl https://openrouter.ai/api/v1/chat/completions \
  -H "Authorization: Bearer <OPENROUTER_API_KEY>" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "openai/gpt-4o",
    "messages": [{ "role": "user", "content": "What is the meaning of life?" }]
  }'

If you want to use a different LLM model, simply change the model parameter.

Here are TLDR version of what are all the other things that you get from it as well:

• Unified Billing & Analytics
• Automatic Fallback
• OpenAI-Compatible Tooling
• Key Provisioning & Rotation
• Bring Your Own Key - BYOK—with a 5% markup charged from your credits.

Integrate with OpenAI-Compatible SDK

Integration is straightforward

Just change the base URL in your SDK configuration:

from openai import OpenAI

client = OpenAI(
  base_url="https://openrouter.ai/api/v1",
  api_key="<OPENROUTER_API_KEY>",
)

completion = client.chat.completions.create(
  model="openai/gpt-4o",
  messages=[
    {
      "role": "user",
      "content": "What is the meaning of life?"
    }
  ]
)

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

For more features and detailed information, check out OpenRouter’s official documentation.

Happy building apps!