diff --git a/jsontime/jsontime.go b/jsontime/jsontime.go
new file mode 100644
index 0000000..51aa8a3
--- /dev/null
+++ b/jsontime/jsontime.go
@@ -0,0 +1,25 @@
+package jsontime
+
+import (
+	"time"
+)
+
+const TimeFormat = "2006-01-02T15:04:05"
+
+type Time time.Time
+
+func Now() Time {
+	return Time(time.Now())
+}
+
+func (t Time) MarshalJSON() ([]byte, error) {
+	stamp := `"` + time.Time(t).Format(TimeFormat) + `"`
+	return []byte(stamp), nil
+}
+
+func (t Time) UnmarshalJSON(data []byte) (err error) {
+	if nativeTime, err := time.Parse(TimeFormat, string(data)); err == nil {
+		t = Time(nativeTime)
+	}
+	return
+}
diff --git a/jsontime/jsontime_test.go b/jsontime/jsontime_test.go
new file mode 100644
index 0000000..040089d
--- /dev/null
+++ b/jsontime/jsontime_test.go
@@ -0,0 +1,29 @@
+package jsontime
+
+import (
+	"encoding/json"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestMarshalTime(t *testing.T) {
+	assert := assert.New(t)
+
+	nativeTime, err := time.Parse(time.RFC3339, "2012-11-01T22:08:41+00:00")
+	assert.Nil(err)
+
+	json, err := Time(nativeTime).MarshalJSON()
+	assert.Nil(err)
+
+	assert.Equal(`"2012-11-01T22:08:41"`, string(json))
+}
+
+func TestUnmarshalTime(t *testing.T) {
+	assert := assert.New(t)
+	jsonTime := Time{}
+
+	err := json.Unmarshal([]byte(`"2012-11-01T22:08:41"`), &jsonTime)
+	assert.Nil(err)
+}
diff --git a/models/nodes.go b/models/nodes.go
index f9e636b..03b862c 100644
--- a/models/nodes.go
+++ b/models/nodes.go
@@ -9,12 +9,13 @@ import (
 	"time"
 
 	"github.com/FreifunkBremen/respond-collector/data"
+	"github.com/FreifunkBremen/respond-collector/jsontime"
 )
 
 // Node struct
 type Node struct {
-	Firstseen  time.Time        `json:"firstseen"`
-	Lastseen   time.Time        `json:"lastseen"`
+	Firstseen  jsontime.Time    `json:"firstseen"`
+	Lastseen   jsontime.Time    `json:"lastseen"`
 	Statistics *data.Statistics `json:"statistics"`
 	Nodeinfo   *data.NodeInfo   `json:"nodeinfo"`
 	Neighbours *data.Neighbours `json:"-"`
@@ -27,7 +28,7 @@ type NodeElement struct {
 // Nodes struct: cache DB of Node's structs
 type Nodes struct {
 	Version   int              `json:"version"`
-	Timestamp time.Time        `json:"timestamp"`
+	Timestamp jsontime.Time    `json:"timestamp"`
 	List      map[string]*Node `json:"nodes"` // the current nodemap, indexed by node ID
 	sync.Mutex
 }
@@ -44,7 +45,7 @@ func NewNodes() *Nodes {
 
 // Update a Node
 func (nodes *Nodes) Update(nodeID string, res *data.ResponseData) {
-	now := time.Now()
+	now := jsontime.Now()
 
 	nodes.Lock()
 	node, _ := nodes.List[nodeID]