curl --request POST \
  --url https://prod-auth.tktchurch.com/oauth/par \
  --header 'Authorization: Basic <encoded-value>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "response_type": "code",
  "client_id": "<string>",
  "redirect_uri": "<string>"
}
'

import Foundation

let parameters = [
  "response_type": "code",
  "client_id": "<string>",
  "redirect_uri": "<string>"
] as [String : Any?]

let postData = try JSONSerialization.data(withJSONObject: parameters, options: [])

let url = URL(string: "https://prod-auth.tktchurch.com/oauth/par")!
var request = URLRequest(url: url)
request.httpMethod = "POST"
request.timeoutInterval = 10
request.allHTTPHeaderFields = [
  "Authorization": "Basic <encoded-value>",
  "Content-Type": "application/json"
]
request.httpBody = postData

let (data, _) = try await URLSession.shared.data(for: request)
print(String(decoding: data, as: UTF8.self))

const options = {
  method: 'POST',
  headers: {Authorization: 'Basic <encoded-value>', 'Content-Type': 'application/json'},
  body: JSON.stringify({response_type: 'code', client_id: '<string>', redirect_uri: '<string>'})
};

fetch('https://prod-auth.tktchurch.com/oauth/par', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

import requests

url = "https://prod-auth.tktchurch.com/oauth/par"

payload = {
    "response_type": "code",
    "client_id": "<string>",
    "redirect_uri": "<string>"
}
headers = {
    "Authorization": "Basic <encoded-value>",
    "Content-Type": "application/json"
}

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

print(response.text)

{
  "request_uri": "urn:ietf:params:oauth:request_uri:AbC12xYz04QwErTyUiOpAsDfGhJkLzXcVbNm",
  "expires_in": 90
}

{
  "error": "invalid_request",
  "error_description": "Redirect URI not registered for this client"
}

{
  "error": "invalid_client",
  "error_description": "Client authentication failed"
}