diff --git a/README.md b/README.md
index 20c0b3e..2439b91 100644
--- a/README.md
+++ b/README.md
@@ -38,6 +38,7 @@ Name | Value | Example value
 `username` | Username of the BOT | `JIRA`
 `icon` | Icon emoji or URL of the BOT | `:speech_baloon:` or `http://.../jira.png`
 `dialect` | Slack API dialect (Default to `slack`) | `slack` or `mattermost`
+`debug` | Dump JIRA and Slack messages to console (Default to `0`) | `0` or `1`
 
 For example:
 
diff --git a/formatter/formatter.go b/formatter/formatter.go
index 8ff1344..5875816 100644
--- a/formatter/formatter.go
+++ b/formatter/formatter.go
@@ -90,7 +90,7 @@ func (f *Formatter) JIRAEventToSlackMessage(event *jira.Event) *message.Message
 // title returns a message title for the JIRA event.
 func (f *Formatter) title(event *jira.Event, verb string, additionalMentions string) string {
 	switch {
-	case event.Issue.Fields.Assignee == nil:
+	case event.Issue.Fields.Assignee.Name == "":
 		return fmt.Sprintf("%s %s the issue: %s",
 			f.Dialect.Mention(event.User.Name),
 			verb,
diff --git a/jira/jira.go b/jira/jira.go
index b9b730f..b1f7757 100644
--- a/jira/jira.go
+++ b/jira/jira.go
@@ -7,13 +7,13 @@ import (
 
 // Event is a JIRA event sent from a JIRA webhook.
 type Event struct {
-	WebhookEvent   string     `json:"webhookEvent"`
-	IssueEventType string     `json:"issue_event_type_name"`
-	Timestamp      int64      `json:"timestamp"`
-	User           *User      `json:"user"`
-	Issue          *Issue     `json:"issue"`
-	Comment        *Comment   `json:"comment"`
-	Changelog      *Changelog `json:"changelog"`
+	WebhookEvent   string    `json:"webhookEvent"`
+	IssueEventType string    `json:"issue_event_type_name"`
+	Timestamp      int64     `json:"timestamp"`
+	User           User      `json:"user"`
+	Issue          Issue     `json:"issue"`
+	Comment        Comment   `json:"comment"`
+	Changelog      Changelog `json:"changelog"`
 }
 
 // IsIssueCreated returns true when an issue is created
@@ -33,7 +33,7 @@ func (s *Event) IsIssueAssigned() bool {
 
 // IsIssueFieldUpdated is sent when the issue is updated
 func (s *Event) IsIssueFieldUpdated(fields ...string) bool {
-	return s.WebhookEvent == "jira:issue_updated" && s.Changelog != nil && s.Changelog.ContainsField(fields...)
+	return s.WebhookEvent == "jira:issue_updated" && s.Changelog.ContainsField(fields...)
 }
 
 // IsIssueDeleted is sent when an issue is deleted
@@ -55,10 +55,10 @@ type User struct {
 type Issue struct {
 	Key    string `json:"key"`
 	Self   string `json:"self"`
-	Fields *struct {
+	Fields struct {
 		Summary     string `json:"summary"`
 		Description string `json:"description"`
-		Assignee    *User  `json:"assignee"`
+		Assignee    User   `json:"assignee"`
 	} `json:"fields"`
 }
 
diff --git a/server/webhook.go b/server/webhook.go
index a6cdf42..03b6917 100644
--- a/server/webhook.go
+++ b/server/webhook.go
@@ -20,6 +20,7 @@ type requestParams struct {
 	username string
 	icon     string
 	dialect  message.Dialect
+	debug    bool
 }
 
 func parseRequestParams(r *http.Request) (*requestParams, error) {
@@ -41,19 +42,21 @@ func parseRequestParams(r *http.Request) (*requestParams, error) {
 	default:
 		return nil, fmt.Errorf("dialect must be slack (default) or mattermost")
 	}
+	switch q.Get("debug") {
+	case "1":
+		p.debug = true
+	}
 	return p, nil
 }
 
 func (h *WebhookHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	defer r.Body.Close()
-
 	p, err := parseRequestParams(r)
 	if err != nil {
 		log.Print(err)
 		http.Error(w, err.Error(), http.StatusBadRequest)
 		return
 	}
-
 	var event jira.Event
 	if err := json.NewDecoder(r.Body).Decode(&event); err != nil {
 		e := fmt.Sprintf("Could not decode the request body: %s", err)
@@ -61,6 +64,10 @@ func (h *WebhookHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, e, http.StatusBadRequest)
 		return
 	}
+	if p.debug {
+		log.Printf("Received parameters %+v", p)
+		log.Printf("Received event %+v", &event)
+	}
 
 	f := formatter.New(p.dialect)
 	m := f.JIRAEventToSlackMessage(&event)
@@ -75,6 +82,9 @@ func (h *WebhookHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	} else {
 		m.IconEmoji = p.icon
 	}
+	if p.debug {
+		log.Printf("Sending %+v", m)
+	}
 	if err := message.Send(p.webhook, m); err != nil {
 		e := fmt.Sprintf("Could not send the message to Slack: %s", err)
 		log.Print(e)
diff --git a/testdata/post_jira_events.sh b/testdata/post_jira_events.sh
index 6f2bb23..f2f2636 100755
--- a/testdata/post_jira_events.sh
+++ b/testdata/post_jira_events.sh
@@ -1,4 +1,7 @@
-#!/bin/sh -xe -o pipefail
+#!/bin/bash
+set -x
+set -e
+set -o pipefail
 
 base_dir="`dirname $0`"