Users can connect to OpenRouter in one click using Proof Key for Code Exchange (PKCE). Here's an example, and here's a step-by-step:

  1. Send your user to https://openrouter.ai/auth?callback_url=YOUR_SITE_URL

    • You can optionally include a code_challenge (random password up to 256 digits) for extra security.
    • For maximum security, we recommend also setting code_challenge_method to S256, and then setting code_challenge to the base64 encoding of the sha256 hash of code_verifier, which you will submit in Step 2. More info in Auth0's docs.
  2. Once logged in, they'll be redirected back to your site with a code in the URL. Make an API call (can be frontend or backend) to exchange the code for a user-controlled API key. And that's it for PKCE!

    • Look for the code query parameter, e.g. ?code=....
fetch('https://openrouter.ai/api/v1/auth/keys', {
  method: 'POST',
  body: JSON.stringify({
    code_verifier: $CODE_VERIFIER, // Only needed if you sent a code_challenge in Step 1
  1. A fresh API key will be in the result under "key". Store it securely and make OpenAI-style requests (supports streaming as well):
fetch("https://openrouter.ai/api/v1/chat/completions", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${OPENROUTER_API_KEY}`,
    "HTTP-Referer": `${YOUR_SITE_URL}`, // Optional, for including your app on openrouter.ai rankings.
    "X-Title": `${YOUR_SITE_NAME}`, // Optional. Shows in rankings on openrouter.ai.
    "Content-Type": "application/json"
  body: JSON.stringify({
    "model": "mistralai/mixtral-8x7b-instruct",
    "messages": [
      {"role": "system", "content": "You are a helpful assistant."},
      {"role": "user", "content": "Hello!"},

You can use JavaScript or any server-side framework, like Streamlit. The linked example shows multiple models and file Q&A.