diff --git a/src/digid_api.rs b/src/digid_api.rs
index 824dbd1..d2d320c 100644
--- a/src/digid_api.rs
+++ b/src/digid_api.rs
@@ -64,10 +64,18 @@ pub struct PolyDataResponse {
     pub result: String,
 }
 
-pub async fn wid_init(session_id: &str) -> Option<ClientContext> {
+pub async fn wid_init(host: &str, session_id: &str) -> Option<ClientContext> {
+    let app_host = if host == "digid.nl" {
+        String::from("app.digid.nl")
+    } else {
+        String::from("app-") + host
+    };
+
+    println!("host: {:?}", app_host);
+
     let client = reqwest::Client::new();
     let init_req = client
-        .post("https://app.digid.nl/apps/wid/new")
+        .post(format!("https://{}/apps/wid/new", app_host))
         .json(&serde_json::json!({"app_session_id": session_id.to_owned() }))
         .header("API-Version", "3")
         .header("App-Version", "6.16.3")
@@ -87,7 +95,7 @@ pub async fn wid_init(session_id: &str) -> Option<ClientContext> {
     }
 
     client
-        .post("https://app.digid.nl/apps/wid/confirm")
+        .post(format!("https://{}/apps/wid/confirm", app_host))
         .json(&serde_json::json!({"app_session_id": session_id.to_owned() }))
         .header("API-Version", "3")
         .header("App-Version", "6.16.3")
diff --git a/src/main.rs b/src/main.rs
index 39d2287..497a168 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,4 +1,4 @@
-use std::{env::args, thread, time::Duration};
+use std::{collections::HashMap, env::args, thread, time::Duration};
 
 use der::{Any, Decode, asn1::SetOfVec, oid::ObjectIdentifier};
 use openssl::{bn::BigNumContext, ec::PointConversionForm, pkey::PKey};
@@ -94,6 +94,7 @@ pub trait Card {
 }
 
 async fn run_auth(
+    host: String,
     session_id: String,
     ctg_pipe: async_channel::Sender<crate::pipe::CardToGUI>,
     gtc_pipe: async_channel::Receiver<crate::pipe::GUIToCard>,
@@ -105,7 +106,7 @@ async fn run_auth(
             service: String::from("UI Test"),
         }
     } else {
-        let Some(ctx) = digid_api::wid_init(&session_id).await else {
+        let Some(ctx) = digid_api::wid_init(&host, &session_id).await else {
             ctg_pipe.send(pipe::CardToGUI::ProcessingMessage { message: "Failed to initialize DigiD session.".to_owned() }).await;
             return Ok(());
         };
@@ -497,17 +498,10 @@ fn main() {
     let (gtc_pipe_s, gtc_pipe_r) = async_channel::unbounded();
 
     let s = args().nth(1).unwrap();
-    let session_id = s
-        .split('&')
-        .next()
-        .unwrap()
-        .split('=')
-        .last()
-        .unwrap()
-        .to_owned();
+    let mut parsed_url = url::form_urlencoded::parse(s.split(':').last().unwrap().as_bytes()).into_owned().collect::<HashMap<String, String>>();
 
     let rt = Runtime::new().unwrap();
-    rt.spawn(async { run_auth(session_id, ctg_pipe_s, gtc_pipe_r).await.unwrap() });
+    rt.spawn(async move { run_auth(parsed_url.remove("host").unwrap_or_else(|| String::from("test")), parsed_url.remove("app_session_id").unwrap_or_else(|| String::from("test")), ctg_pipe_s, gtc_pipe_r).await.unwrap() });
 
     gui::run_gui(ctg_pipe_r, gtc_pipe_s);
 }