Could you please tryout in Postman to see if it works for you? Here is a collection you can use as a template for the requests (it is not possible to upload a .json file here, so please copy the text into a textfile and change the file format to .json)
Let me know if it works for you. Otherwise I am happy to send you the Postman collection via mail.
{
"info": {
"_postman_id": "64e6ad3a-b1dd-4fef-995b-a23972fc3fab",
"name": "VIessmann API - Authentication",
"description": "This is a Postman collection for the Viessmann API. It contains the following section:\n\n* Authentication\n \n\nFor general steps to get started, please go to the API documentation page 'getting started': [https://documentation.viessmann.com/static/get-started](https://documentation.viessmann.com/static/g...)",
"schema": "https://schema.getpostman.com/json/collection/v2.1.0/collection.json"
},
"item": [
{
"name": "Authorization request",
"request": {
"method": "GET",
"header": [
{
"key": "Content-Type",
"name": "Content-Type",
"value": "application/x-www-form-urlencoded",
"type": "text"
}
],
"url": {
"raw": "https://iam.viessmann.com/idp/v2/authorize?client_id={{client_id}}&redirect_uri=http://localhost:420... User offline_access",
"protocol": "https",
"host": [
"iam",
"viessmann",
"com"
],
"path": [
"idp",
"v2",
"authorize"
],
"query": [
{
"key": "client_id",
"value": "{{client_id}}"
},
{
"key": "redirect_uri",
"value": "http://localhost:4200/"
},
{
"key": "response_type",
"value": "code"
},
{
"key": "code_challenge",
"value": "{{code_challenge}}"
},
{
"key": "scope",
"value": "IoT User offline_access"
}
]
},
"description": "The /authorize endpoint of our IAM platform is used to request an authorization code."
},
"response": []
},
{
"name": "Authorization code exchange",
"request": {
"method": "POST",
"header": [
{
"key": "Content-Type",
"name": "Content-Type",
"value": "application/x-www-form-urlencoded",
"type": "text"
}
],
"body": {
"mode": "urlencoded",
"urlencoded": []
},
"url": {
"raw": "https://iam.viessmann.com/idp/v2/token?grant_type=authorization_code&client_id={{client_id}}&redirec...}}",
"protocol": "https",
"host": [
"iam",
"viessmann",
"com"
],
"path": [
"idp",
"v2",
"token"
],
"query": [
{
"key": "grant_type",
"value": "authorization_code"
},
{
"key": "client_id",
"value": "{{client_id}}"
},
{
"key": "redirect_uri",
"value": "http://localhost:4200/"
},
{
"key": "code_verifier",
"value": "{{code_challenge}}"
},
{
"key": "code",
"value": "{{code}}"
}
]
},
"description": "With the authorization code you can request an access token."
},
"response": []
},
{
"name": "Authorization code exchange - with Refresh Token",
"request": {
"method": "POST",
"header": [
{
"key": "Content-Type",
"name": "Content-Type",
"value": "application/x-www-form-urlencoded",
"type": "text"
}
],
"body": {
"mode": "urlencoded",
"urlencoded": []
},
"url": {
"raw": "https://iam.viessmann.com/idp/v2/token?client_id={{client_id}}&grant_type=refresh_token&refresh_toke...}}",
"protocol": "https",
"host": [
"iam",
"viessmann",
"com"
],
"path": [
"idp",
"v2",
"token"
],
"query": [
{
"key": "client_id",
"value": "{{client_id}}"
},
{
"key": "grant_type",
"value": "refresh_token"
},
{
"key": "refresh_token",
"value": "{{refresh_token}}"
}
]
},
"description": "With the authorization code you can request an access token."
},
"response": []
}
],
"event": [
{
"listen": "prerequest",
"script": {
"type": "text/javascript",
"exec": [
""
]
}
},
{
"listen": "test",
"script": {
"type": "text/javascript",
"exec": [
""
]
}
}
]
}
