curl --request POST \
  --url https://openrouter.ai/api/v1/oauth/token \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/x-www-form-urlencoded' \
  --data federation_policy_id=4b2f7d1e-8c3a-4e5f-9a6b-1c2d3e4f5a6b \
  --data grant_type=urn:ietf:params:oauth:grant-type:token-exchange \
  --data 'subject_token=<jwt from your identity provider>' \
  --data subject_token_type=urn:ietf:params:oauth:token-type:jwt

import requests

url = "https://openrouter.ai/api/v1/oauth/token"

payload = {
    "federation_policy_id": "4b2f7d1e-8c3a-4e5f-9a6b-1c2d3e4f5a6b",
    "grant_type": "urn:ietf:params:oauth:grant-type:token-exchange",
    "subject_token": "<jwt from your identity provider>",
    "subject_token_type": "urn:ietf:params:oauth:token-type:jwt"
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/x-www-form-urlencoded"
}

response = requests.post(url, data=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {
    Authorization: 'Bearer <token>',
    'Content-Type': 'application/x-www-form-urlencoded'
  },
  body: new URLSearchParams({
    federation_policy_id: '4b2f7d1e-8c3a-4e5f-9a6b-1c2d3e4f5a6b',
    grant_type: 'urn:ietf:params:oauth:grant-type:token-exchange',
    subject_token: '<jwt from your identity provider>',
    subject_token_type: 'urn:ietf:params:oauth:token-type:jwt'
  })
};

fetch('https://openrouter.ai/api/v1/oauth/token', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://openrouter.ai/api/v1/oauth/token",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => "federation_policy_id=4b2f7d1e-8c3a-4e5f-9a6b-1c2d3e4f5a6b&grant_type=urn%3Aietf%3Aparams%3Aoauth%3Agrant-type%3Atoken-exchange&subject_token=%3Cjwt%20from%20your%20identity%20provider%3E&subject_token_type=urn%3Aietf%3Aparams%3Aoauth%3Atoken-type%3Ajwt",
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/x-www-form-urlencoded"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://openrouter.ai/api/v1/oauth/token"

	payload := strings.NewReader("federation_policy_id=4b2f7d1e-8c3a-4e5f-9a6b-1c2d3e4f5a6b&grant_type=urn%3Aietf%3Aparams%3Aoauth%3Agrant-type%3Atoken-exchange&subject_token=%3Cjwt%20from%20your%20identity%20provider%3E&subject_token_type=urn%3Aietf%3Aparams%3Aoauth%3Atoken-type%3Ajwt")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/x-www-form-urlencoded")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://openrouter.ai/api/v1/oauth/token")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/x-www-form-urlencoded")
  .body("federation_policy_id=4b2f7d1e-8c3a-4e5f-9a6b-1c2d3e4f5a6b&grant_type=urn%3Aietf%3Aparams%3Aoauth%3Agrant-type%3Atoken-exchange&subject_token=%3Cjwt%20from%20your%20identity%20provider%3E&subject_token_type=urn%3Aietf%3Aparams%3Aoauth%3Atoken-type%3Ajwt")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://openrouter.ai/api/v1/oauth/token")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/x-www-form-urlencoded'
request.body = "federation_policy_id=4b2f7d1e-8c3a-4e5f-9a6b-1c2d3e4f5a6b&grant_type=urn%3Aietf%3Aparams%3Aoauth%3Agrant-type%3Atoken-exchange&subject_token=%3Cjwt%20from%20your%20identity%20provider%3E&subject_token_type=urn%3Aietf%3Aparams%3Aoauth%3Atoken-type%3Ajwt"

response = http.request(request)
puts response.read_body

{
  "access_token": "<short-lived openrouter access token jwt>",
  "expires_in": 900,
  "issued_token_type": "urn:ietf:params:oauth:token-type:access_token",
  "scope": "inference",
  "token_type": "Bearer"
}

{
  "error": "invalid_grant",
  "error_description": "The subject token was not accepted."
}

{
  "error": "invalid_grant",
  "error_description": "The subject token was not accepted."
}

{
  "error": "invalid_grant",
  "error_description": "The subject token was not accepted."
}

{
  "error": "invalid_grant",
  "error_description": "The subject token was not accepted."
}