diff --git a/src/middleware.rs b/src/middleware.rs
index 452add9..2d991de 100644
--- a/src/middleware.rs
+++ b/src/middleware.rs
@@ -1,10 +1,10 @@
+mod deadline;
 mod metrics;
 mod payload;
 
 use actix_web::{
     dev::{Service, ServiceRequest, Transform},
     http::StatusCode,
-    rt::time::Timeout,
     HttpResponse, ResponseError,
 };
 use std::{
@@ -13,41 +13,10 @@ use std::{
     task::{Context, Poll},
 };
 
-use crate::future::WithTimeout;
-
+pub(crate) use self::deadline::Deadline;
 pub(crate) use self::metrics::Metrics;
 pub(crate) use self::payload::Payload;
 
-pub(crate) struct Deadline;
-pub(crate) struct DeadlineMiddleware<S> {
-    inner: S,
-}
-
-#[derive(Debug)]
-struct DeadlineExceeded;
-
-pin_project_lite::pin_project! {
-    pub(crate) struct DeadlineFuture<F> {
-        #[pin]
-        inner: DeadlineFutureInner<F>,
-    }
-}
-
-pin_project_lite::pin_project! {
-    #[project = DeadlineFutureInnerProj]
-    #[project_replace = DeadlineFutureInnerProjReplace]
-    enum DeadlineFutureInner<F> {
-        Timed {
-            #[pin]
-            timeout: Timeout<F>,
-        },
-        Untimed {
-            #[pin]
-            future: F,
-        },
-    }
-}
-
 pub(crate) struct Internal(pub(crate) Option<String>);
 pub(crate) struct InternalMiddleware<S>(Option<String>, S);
 #[derive(Clone, Debug, thiserror::Error)]
@@ -83,124 +52,6 @@ impl ResponseError for ApiError {
     }
 }
 
-impl<S> Transform<S, ServiceRequest> for Deadline
-where
-    S: Service<ServiceRequest>,
-    S::Future: 'static,
-    actix_web::Error: From<S::Error>,
-{
-    type Response = S::Response;
-    type Error = actix_web::Error;
-    type InitError = ();
-    type Transform = DeadlineMiddleware<S>;
-    type Future = Ready<Result<Self::Transform, Self::InitError>>;
-
-    fn new_transform(&self, service: S) -> Self::Future {
-        ready(Ok(DeadlineMiddleware { inner: service }))
-    }
-}
-
-impl<S> Service<ServiceRequest> for DeadlineMiddleware<S>
-where
-    S: Service<ServiceRequest>,
-    S::Future: 'static,
-    actix_web::Error: From<S::Error>,
-{
-    type Response = S::Response;
-    type Error = actix_web::Error;
-    type Future = DeadlineFuture<S::Future>;
-
-    fn poll_ready(&self, cx: &mut core::task::Context<'_>) -> Poll<Result<(), Self::Error>> {
-        self.inner
-            .poll_ready(cx)
-            .map(|res| res.map_err(actix_web::Error::from))
-    }
-
-    fn call(&self, req: ServiceRequest) -> Self::Future {
-        let duration = req
-            .headers()
-            .get("X-Request-Deadline")
-            .and_then(|deadline| {
-                let deadline = time::OffsetDateTime::from_unix_timestamp_nanos(
-                    deadline.to_str().ok()?.parse().ok()?,
-                )
-                .ok()?;
-                let now = time::OffsetDateTime::now_utc();
-
-                if now < deadline {
-                    Some((deadline - now).try_into().ok()?)
-                } else {
-                    Some(std::time::Duration::from_secs(0))
-                }
-            });
-        DeadlineFuture::new(self.inner.call(req), duration)
-    }
-}
-
-impl std::fmt::Display for DeadlineExceeded {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "Deadline exceeded")
-    }
-}
-
-impl std::error::Error for DeadlineExceeded {}
-impl actix_web::error::ResponseError for DeadlineExceeded {
-    fn status_code(&self) -> StatusCode {
-        StatusCode::REQUEST_TIMEOUT
-    }
-
-    fn error_response(&self) -> HttpResponse {
-        HttpResponse::build(self.status_code())
-            .content_type("application/json")
-            .body(
-                serde_json::to_string(
-                    &serde_json::json!({ "msg": self.to_string(), "code": "request-timeout" }),
-                )
-                .unwrap_or_else(|_| {
-                    r#"{"msg":"request timeout","code":"request-timeout"}"#.to_string()
-                }),
-            )
-    }
-}
-
-impl<F> DeadlineFuture<F>
-where
-    F: Future,
-{
-    fn new(future: F, timeout: Option<std::time::Duration>) -> Self {
-        DeadlineFuture {
-            inner: match timeout {
-                Some(duration) => DeadlineFutureInner::Timed {
-                    timeout: future.with_timeout(duration),
-                },
-                None => DeadlineFutureInner::Untimed { future },
-            },
-        }
-    }
-}
-
-impl<F, R, E> Future for DeadlineFuture<F>
-where
-    F: Future<Output = Result<R, E>>,
-    actix_web::Error: From<E>,
-{
-    type Output = Result<R, actix_web::Error>;
-
-    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
-        let this = self.as_mut().project();
-
-        match this.inner.project() {
-            DeadlineFutureInnerProj::Timed { timeout } => timeout.poll(cx).map(|res| match res {
-                Ok(res) => res.map_err(actix_web::Error::from),
-                Err(_) => Err(DeadlineExceeded.into()),
-            }),
-            DeadlineFutureInnerProj::Untimed { future } => future
-                .poll(cx)
-                .map(|res| res.map_err(actix_web::Error::from)),
-        }
-    }
-}
-
 impl<S> Transform<S, ServiceRequest> for Internal
 where
     S: Service<ServiceRequest, Error = actix_web::Error>,
diff --git a/src/middleware/deadline.rs b/src/middleware/deadline.rs
new file mode 100644
index 0000000..c6ddb43
--- /dev/null
+++ b/src/middleware/deadline.rs
@@ -0,0 +1,195 @@
+use actix_web::{
+    dev::{Service, ServiceRequest, Transform},
+    http::StatusCode,
+    rt::time::Timeout,
+    HttpResponse, ResponseError,
+};
+use std::{
+    future::{ready, Future, Ready},
+    pin::Pin,
+    task::{Context, Poll},
+    time::Duration,
+};
+
+use crate::future::WithTimeout;
+
+pub(crate) struct Deadline;
+pub(crate) struct DeadlineMiddleware<S> {
+    inner: S,
+}
+
+#[derive(Debug, thiserror::Error)]
+#[error("Deadline exceeded")]
+struct DeadlineExceeded;
+
+#[derive(Debug, thiserror::Error)]
+enum ParseDeadlineError {
+    #[error("Invalid header string")]
+    HeaderString,
+
+    #[error("Invalid deadline format")]
+    HeaderFormat,
+
+    #[error("Invalid deadline timestmap")]
+    Timestamp,
+
+    #[error("Invalid deadline duration")]
+    Duration,
+}
+
+pin_project_lite::pin_project! {
+    pub(crate) struct DeadlineFuture<F> {
+        #[pin]
+        inner: DeadlineFutureInner<F>,
+    }
+}
+
+pin_project_lite::pin_project! {
+    #[project = DeadlineFutureInnerProj]
+    #[project_replace = DeadlineFutureInnerProjReplace]
+    enum DeadlineFutureInner<F> {
+        Timed {
+            #[pin]
+            timeout: Timeout<F>,
+        },
+        Untimed {
+            #[pin]
+            future: F,
+        },
+        Error {
+            error: Option<ParseDeadlineError>,
+        },
+    }
+}
+
+impl<S> Transform<S, ServiceRequest> for Deadline
+where
+    S: Service<ServiceRequest>,
+    S::Future: 'static,
+    actix_web::Error: From<S::Error>,
+{
+    type Response = S::Response;
+    type Error = actix_web::Error;
+    type InitError = ();
+    type Transform = DeadlineMiddleware<S>;
+    type Future = Ready<Result<Self::Transform, Self::InitError>>;
+
+    fn new_transform(&self, service: S) -> Self::Future {
+        ready(Ok(DeadlineMiddleware { inner: service }))
+    }
+}
+
+impl<S> Service<ServiceRequest> for DeadlineMiddleware<S>
+where
+    S: Service<ServiceRequest>,
+    S::Future: 'static,
+    actix_web::Error: From<S::Error>,
+{
+    type Response = S::Response;
+    type Error = actix_web::Error;
+    type Future = DeadlineFuture<S::Future>;
+
+    fn poll_ready(&self, cx: &mut core::task::Context<'_>) -> Poll<Result<(), Self::Error>> {
+        self.inner
+            .poll_ready(cx)
+            .map(|res| res.map_err(actix_web::Error::from))
+    }
+
+    fn call(&self, req: ServiceRequest) -> Self::Future {
+        let duration: Result<Option<Duration>, ParseDeadlineError> = req
+            .headers()
+            .get("X-Request-Deadline")
+            .map(|deadline| {
+                let deadline_str = deadline
+                    .to_str()
+                    .map_err(|_| ParseDeadlineError::HeaderString)?;
+
+                let deadline_i128 = deadline_str
+                    .parse()
+                    .map_err(|_| ParseDeadlineError::HeaderFormat)?;
+
+                let deadline = time::OffsetDateTime::from_unix_timestamp_nanos(deadline_i128)
+                    .map_err(|_| ParseDeadlineError::Timestamp)?;
+
+                let now = time::OffsetDateTime::now_utc();
+
+                if now < deadline {
+                    (deadline - now)
+                        .try_into()
+                        .map_err(|_| ParseDeadlineError::Duration)
+                } else {
+                    Ok(Duration::from_secs(0))
+                }
+            })
+            .transpose();
+        DeadlineFuture::new(self.inner.call(req), duration)
+    }
+}
+
+impl ResponseError for DeadlineExceeded {
+    fn status_code(&self) -> StatusCode {
+        StatusCode::REQUEST_TIMEOUT
+    }
+
+    fn error_response(&self) -> HttpResponse {
+        HttpResponse::build(self.status_code()).json(serde_json::json!({
+            "msg": self.to_string(),
+            "code": "request-timeout"
+        }))
+    }
+}
+
+impl ResponseError for ParseDeadlineError {
+    fn status_code(&self) -> StatusCode {
+        StatusCode::BAD_REQUEST
+    }
+
+    fn error_response(&self) -> HttpResponse<actix_web::body::BoxBody> {
+        HttpResponse::build(self.status_code()).json(serde_json::json!({
+            "msg": self.to_string(),
+            "code": "parse-deadline"
+        }))
+    }
+}
+
+impl<F> DeadlineFuture<F>
+where
+    F: Future,
+{
+    fn new(future: F, timeout: Result<Option<Duration>, ParseDeadlineError>) -> Self {
+        DeadlineFuture {
+            inner: match timeout {
+                Ok(Some(duration)) => DeadlineFutureInner::Timed {
+                    timeout: future.with_timeout(duration),
+                },
+                Ok(None) => DeadlineFutureInner::Untimed { future },
+                Err(e) => DeadlineFutureInner::Error { error: Some(e) },
+            },
+        }
+    }
+}
+
+impl<F, R, E> Future for DeadlineFuture<F>
+where
+    F: Future<Output = Result<R, E>>,
+    actix_web::Error: From<E>,
+{
+    type Output = Result<R, actix_web::Error>;
+
+    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+        let this = self.as_mut().project();
+
+        match this.inner.project() {
+            DeadlineFutureInnerProj::Timed { timeout } => timeout.poll(cx).map(|res| match res {
+                Ok(res) => res.map_err(actix_web::Error::from),
+                Err(_) => Err(DeadlineExceeded.into()),
+            }),
+            DeadlineFutureInnerProj::Untimed { future } => future
+                .poll(cx)
+                .map(|res| res.map_err(actix_web::Error::from)),
+            DeadlineFutureInnerProj::Error { error } => {
+                Poll::Ready(Err(error.take().expect("Polled after completion").into()))
+            }
+        }
+    }
+}