diff --git a/src/core/pay_request.rs b/src/core/pay_request.rs
index cdd8974..dc35737 100644
--- a/src/core/pay_request.rs
+++ b/src/core/pay_request.rs
@@ -180,6 +180,17 @@ impl std::str::FromStr for CallbackResponse {
     }
 }
 
+impl std::fmt::Display for CallbackResponse {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let cr = ser::CallbackResponse {
+            disposable: self.disposable,
+            pr: &self.pr,
+        };
+
+        f.write_str(&miniserde::json::to_string(&cr))
+    }
+}
+
 mod ser {
     use crate::serde::Url;
     use miniserde::Serialize;
@@ -199,6 +210,12 @@ mod ser {
         #[serde(rename = "successAction")]
         pub success_action: Option<BTreeMap<&'static str, std::borrow::Cow<'a, str>>>,
     }
+
+    #[derive(Serialize)]
+    pub(super) struct CallbackResponse<'a> {
+        pub pr: &'a str,
+        pub disposable: bool,
+    }
 }
 
 mod de {
diff --git a/src/server.rs b/src/server.rs
index 9529e45..10bf2a5 100644
--- a/src/server.rs
+++ b/src/server.rs
@@ -1,33 +1,86 @@
 use axum::{http::StatusCode, routing::get, Router};
 use std::future::Future;
 
-#[must_use]
-pub fn builder<P>() -> Server<P> {
-    Server { pay_request: None }
+pub struct Server<PQ, PC> {
+    pay_request_query: PQ,
+    pay_request_callback: PC,
 }
 
-pub struct Server<P> {
-    pub pay_request: Option<P>,
+impl Default
+    for Server<
+        unimplemented::Handler<crate::core::pay_request::PayRequest>,
+        unimplemented::Handler<crate::core::pay_request::CallbackResponse>,
+    >
+{
+    fn default() -> Self {
+        Server {
+            pay_request_query: unimplemented::handler,
+            pay_request_callback: unimplemented::handler,
+        }
+    }
 }
 
-impl<P, PFut> Server<P>
+impl<PQ, PC> Server<PQ, PC> {
+    pub fn pay_request<PQ2, PC2>(
+        self,
+        pay_request_query: PQ2,
+        pay_request_callback: PC2,
+    ) -> Server<PQ2, PC2> {
+        Server {
+            pay_request_query,
+            pay_request_callback,
+        }
+    }
+}
+
+impl<PQ, PQFut, PC, PCFut> Server<PQ, PC>
 where
-    P: 'static + Send + Clone + Fn() -> PFut,
-    PFut: Send + Future<Output = Result<crate::core::pay_request::PayRequest, StatusCode>>,
+    PQ: 'static + Send + Clone + Fn() -> PQFut,
+    PQFut: Send + Future<Output = Result<crate::core::pay_request::PayRequest, StatusCode>>,
+    PC: 'static + Send + Clone + Fn() -> PCFut,
+    PCFut: Send + Future<Output = Result<crate::core::pay_request::CallbackResponse, StatusCode>>,
 {
     pub fn build(self) -> Router<()> {
-        let mut router = Router::new();
-
-        if let Some(p) = self.pay_request {
-            router = router.route(
+        Router::new()
+            .route(
                 "/lnurlp",
                 get(move || {
-                    let p = p.clone();
-                    async move { p().await.map(|a| a.to_string()) }
+                    let pq = self.pay_request_query.clone();
+                    async move { pq().await.map(|a| a.to_string()) }
+                }),
+            )
+            .route(
+                "/lnurlp/callback",
+                get(move || {
+                    let pc = self.pay_request_callback.clone();
+                    async move { pc().await.map(|a| a.to_string()) }
                 }),
-            );
+            )
+    }
+}
+
+mod unimplemented {
+    use axum::http::StatusCode;
+    use std::{
+        future::Future,
+        marker::PhantomData,
+        pin::Pin,
+        task::{Context, Poll},
+    };
+
+    pub(super) type Handler<T> = fn() -> Unimplemented<T>;
+
+    pub struct Unimplemented<T>(PhantomData<T>);
+
+    impl<T> Future for Unimplemented<T> {
+        type Output = Result<T, StatusCode>;
+
+        fn poll(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Result<T, StatusCode>> {
+            Poll::Ready(Err(StatusCode::NOT_IMPLEMENTED))
         }
+    }
 
-        router
+    pub(super) fn handler<T>() -> Unimplemented<T> {
+        Unimplemented(PhantomData)
     }
 }
diff --git a/tests/lud06.rs b/tests/lud06.rs
index b4ba913..d8b23a1 100644
--- a/tests/lud06.rs
+++ b/tests/lud06.rs
@@ -9,29 +9,32 @@ async fn test() {
     let query_url = format!("http://{addr}/lnurlp");
     let callback_url = url::Url::parse(&format!("http://{addr}/lnurlp/callback")).expect("url");
 
-    let router = {
-        let mut router = lnurlkit::server::builder();
-
-        router.pay_request = Some(move || {
-            let callback = callback_url.clone();
-
-            async {
-                Ok(lnurlkit::core::pay_request::PayRequest {
-                    callback,
-                    short_description: String::from("today i become death"),
-                    long_description: Some(String::from("the destroyer of worlds")),
-                    success_action: None,
-                    jpeg: None,
-                    png: None,
-                    comment_size: 0,
-                    min: 314,
-                    max: 315,
+    let router = lnurlkit::server::Server::default()
+        .pay_request(
+            move || {
+                let callback = callback_url.clone();
+                async {
+                    Ok(lnurlkit::core::pay_request::PayRequest {
+                        callback,
+                        short_description: String::from("today i become death"),
+                        long_description: Some(String::from("the destroyer of worlds")),
+                        success_action: None,
+                        jpeg: None,
+                        png: None,
+                        comment_size: 0,
+                        min: 314,
+                        max: 315,
+                    })
+                }
+            },
+            move || async {
+                Ok(lnurlkit::core::pay_request::CallbackResponse {
+                    pr: String::from("pierre"),
+                    disposable: false,
                 })
-            }
-        });
-
-        router.build()
-    };
+            },
+        )
+        .build();
 
     tokio::spawn(async move {
         axum::serve(listener, router).await.expect("serve");
@@ -57,9 +60,13 @@ async fn test() {
     assert_eq!(pr.core.min, 314);
     assert_eq!(pr.core.max, 315);
     assert_eq!(pr.core.short_description, "today i become death");
-    assert_eq!(pr.core.long_description.unwrap(), "the destroyer of worlds");
+    assert_eq!(
+        pr.core.long_description.as_ref().unwrap(),
+        "the destroyer of worlds"
+    );
 
-    // let invoice = pr.callback("comment", 123000).await.expect("callback");
+    let invoice = pr.callback("comment", 314).await.expect("callback");
 
-    // println!("{invoice:?}");
+    assert_eq!(invoice.pr, "pierre");
+    assert!(!invoice.disposable);
 }