diff --git a/api/client.go b/api/client.go
new file mode 100644
index 0000000..de21dc5
--- /dev/null
+++ b/api/client.go
@@ -0,0 +1,89 @@
+package api
+
+import (
+	"sync"
+
+	"github.com/eosswedenorg/thalos/api/message"
+)
+
+type handler func([]byte)
+
+// Client reads and decodes messages from a reader and provides callback functions.
+type Client struct {
+	reader  Reader
+	decoder message.Decoder
+
+	wg sync.WaitGroup
+
+	OnError     func(error)
+	OnAction    func(message.ActionTrace)
+	OnHeartbeat func(message.HeartBeat)
+}
+
+func NewClient(reader Reader, decoder message.Decoder) *Client {
+	return &Client{
+		reader:  reader,
+		decoder: decoder,
+	}
+}
+
+func (c *Client) worker(channel Channel, h handler) {
+	for {
+		payload, err := c.reader.Read(channel)
+		if err != nil {
+			if c.OnError != nil {
+				c.OnError(err)
+			}
+			return
+		}
+
+		h(payload)
+	}
+}
+
+func (c *Client) actHandler(payload []byte) {
+	var act message.ActionTrace
+	if err := c.decoder(payload, &act); err != nil {
+		if c.OnError != nil {
+			c.OnError(err)
+		}
+		return
+	}
+	c.OnAction(act)
+}
+
+func (c *Client) hbHandler(payload []byte) {
+	var hb message.HeartBeat
+	if err := c.decoder(payload, &hb); err != nil {
+		if c.OnError != nil {
+			c.OnError(err)
+		}
+		return
+	}
+	c.OnHeartbeat(hb)
+}
+
+func (c *Client) Subscribe(channel Channel) {
+	var handler handler
+
+	if HeartbeatChannel.Is(channel) {
+		handler = c.hbHandler
+	} else {
+		handler = c.actHandler
+	}
+
+	// Start a worker for this channel.
+	c.wg.Add(1)
+	go func() {
+		defer c.wg.Done()
+		c.worker(channel, handler)
+	}()
+}
+
+func (c *Client) Run() {
+	c.wg.Wait()
+}
+
+func (c *Client) Close() error {
+	return c.reader.Close()
+}