diff --git a/server.ss b/server.ss
index 03f265d..184c7f7 100755
--- a/server.ss
+++ b/server.ss
@@ -2,8 +2,11 @@
 
 (export main)
 
-(import :std/getopt
+(import :std/format
+	:std/getopt
 	:std/iter
+	:std/logger
+	:std/net/address
 	:std/net/httpd
 	:std/srfi/19
 	:std/sugar
@@ -19,54 +22,70 @@
 
   (try
    (let (opt (getopt-parse gopt args))
-     (run (hash-get opt 'address)))
+     (parameterize ((current-logger-options 'DEBUG))
+       (start-logger!)
+       (run (hash-get opt 'address))))
    (catch (getopt-error? exn)
      (getopt-display-help exn "server" (current-error-port))
      (exit 1))))
 
 (def (run address)
+  (infof "Starting HTTP server on ~a" (inet-address->string address))
   (let (httpd (start-http-server! address mux: (make-default-http-mux default-handler)))
     (http-register-handler httpd "/" departures-handler)
     (thread-join! httpd)))
 
 ;; /
 (def (departures-handler req res)
-  (def sncf-key (getenv "SNCF_AUTH_KEY" #f))
-  (unless sncf-key
-    (display "No SNCF API authentication key found. Set the SNCF_AUTH_KEY environment variable.\n"
-	     (current-error-port))
-    (exit 1))
-  (def headers (http-request-headers req))
-  (def accept-header (assoc "Accept" headers))
-  (when accept-header (set! accept-header (cdr accept-header)))
-  (def params (parse-request-params (http-request-params req)))
-  (def station (assoc "station" params))
-  (when station (set! station (cdr station)))
-  (def datetime-str (assoc "datetime" params))
-  (def datetime (if datetime-str
-		  (string->date (cdr datetime-str) "~Y~m~dT~H~M~S")
-		  #f))
-  (define-values (station-name station-id)
-    (if station
-      (get-station-id sncf-key station)
-      (values "Vernon - Giverny (Vernon)" "stop_area:SNCF:87415604")))
-  (define-values (departures disruptions) (get-departures sncf-key station-id datetime))
-  (def content
-    (cond
-     ((or (assoc "markdown" params) (string-prefix? "text/markdown" accept-header))
-      (with-output-to-string
-	(lambda () (display-all departures disruptions station-name datetime
-			   style: 'markdown))))
-     ((string-prefix? "text/html" accept-header) ; TODO
-      (with-output-to-string
-	(lambda () (display-all departures disruptions station-name datetime
-			   style: 'markdown))))
-     (#t
-      (with-output-to-string
-	(lambda () (display-all departures disruptions station-name datetime
-			   style: 'unicode))))))
-  (http-response-write res 200 '(("Content-Type" . "text/plain; charset=utf-8"))
-		       content))
+  (let/cc return
+    (infof "~a ~a ~a"
+	   (http-request-method req)
+	   (http-request-path req)
+	   (inet-address->string (http-request-client req)))
+    (def sncf-key (getenv "SNCF_AUTH_KEY" #f))
+    (unless sncf-key
+      (errorf "No SNCF API authentication key found. Set the SNCF_AUTH_KEY environment variable.")
+      (http-response-write res 500 '(("Content-Type" . "text/plain; charset=utf-8"))
+			   "Missing SNCF API authentication key\n")
+      (return))
+    (def headers (http-request-headers req))
+    (def accept-header (assoc "Accept" headers))
+    (when accept-header (set! accept-header (cdr accept-header)))
+    (def params (parse-request-params (http-request-params req)))
+    (def station (assoc "station" params))
+    (when station (set! station (cdr station)))
+    (def datetime-str (assoc "datetime" params))
+    (def datetime (if datetime-str
+		    (try
+		     (string->date (cdr datetime-str) "~Y~m~dT~H~M~S")
+		     (catch _
+		       (warnf "Badly formatted date string: ~a" (cdr datetime-str))
+		       (http-response-write res 400 '(("Content-Type" . "text/plain; charset=utf-8"))
+					    (format "Badly formatted date string, expected %Y%m%dT%H%M%S: ~a\n"
+						    (cdr datetime-str)))
+		       (return)))
+		    #f))
+    (define-values (station-name station-id)
+      (if (string? station)
+	(get-station-id sncf-key station)
+	(values "Vernon - Giverny (Vernon)" "stop_area:SNCF:87415604")))
+    (define-values (departures disruptions) (get-departures sncf-key station-id datetime))
+    (def content
+      (cond
+       ((or (assoc "markdown" params) (string-prefix? "text/markdown" accept-header))
+	(with-output-to-string
+	  (lambda () (display-all departures disruptions station-name datetime
+			     style: 'markdown))))
+       ((string-prefix? "text/html" accept-header) ; TODO
+	(with-output-to-string
+	  (lambda () (display-all departures disruptions station-name datetime
+			     style: 'markdown))))
+       (#t
+	(with-output-to-string
+	  (lambda () (display-all departures disruptions station-name datetime
+			     style: 'unicode))))))
+    (http-response-write res 200 '(("Content-Type" . "text/plain; charset=utf-8"))
+			 content)))
 
 (def (parse-request-params params)
   (if params