diff --git i/whisper/whisperv6/doc.go w/whisper/whisperv6/doc.go
index 066a9766d..4bbf5546b 100644
--- i/whisper/whisperv6/doc.go
+++ w/whisper/whisperv6/doc.go
@@ -95,3 +95,40 @@ type MailServer interface {
 	Archive(env *Envelope)
 	DeliverMail(whisperPeer *Peer, request *Envelope)
 }
+
+type envelopeSource int
+
+const (
+	_ = iota
+	// peerSource indicates a source as a regular peer.
+	peerSource envelopeSource = iota
+	// p2pSource indicates that envelop was received from a trusted peer.
+	p2pSource
+)
+
+// EnvelopeMeta keeps metadata of received envelopes.
+type EnvelopeMeta struct {
+	Hash   string
+	Topic  TopicType
+	Size   uint32
+	Source envelopeSource
+	IsNew  bool
+	Peer   string
+}
+
+// SourceString converts source to string.
+func (m *EnvelopeMeta) SourceString() string {
+	switch m.Source {
+	case peerSource:
+		return "peer"
+	case p2pSource:
+		return "p2p"
+	default:
+		return "unknown"
+	}
+}
+
+// EnvelopeTracer tracks received envelopes.
+type EnvelopeTracer interface {
+	Trace(*EnvelopeMeta)
+}
diff --git i/whisper/whisperv6/whisper.go w/whisper/whisperv6/whisper.go
index 702556079..9aaf5687c 100644
--- i/whisper/whisperv6/whisper.go
+++ w/whisper/whisperv6/whisper.go
@@ -87,7 +87,8 @@ type Whisper struct {
 	statsMu sync.Mutex // guard stats
 	stats   Statistics // Statistics of whisper node
 
-	mailServer MailServer // MailServer interface
+	mailServer     MailServer     // MailServer interface
+	envelopeTracer EnvelopeTracer // Service collecting envelopes metadata
 }
 
 // New creates a Whisper client ready to communicate through the Ethereum P2P network.
@@ -211,6 +212,12 @@ func (whisper *Whisper) RegisterServer(server MailServer) {
 	whisper.mailServer = server
 }
 
+// RegisterEnvelopeTracer registers an EnveloperTracer to collect information
+// about received envelopes.
+func (whisper *Whisper) RegisterEnvelopeTracer(tracer EnvelopeTracer) {
+	whisper.envelopeTracer = tracer
+}
+
 // Protocols returns the whisper sub-protocols ran by this particular client.
 func (whisper *Whisper) Protocols() []p2p.Protocol {
 	return []p2p.Protocol{whisper.protocol}
@@ -736,6 +743,7 @@ func (whisper *Whisper) runMessageLoop(p *Peer, rw p2p.MsgReadWriter) error {
 
 			trouble := false
 			for _, env := range envelopes {
+				whisper.traceEnvelope(env, !whisper.isEnvelopeCached(env.Hash()), peerSource, p)
 				cached, err := whisper.add(env, whisper.lightClient)
 				if err != nil {
 					trouble = true
@@ -786,6 +794,7 @@ func (whisper *Whisper) runMessageLoop(p *Peer, rw p2p.MsgReadWriter) error {
 					return errors.New("invalid direct message")
 				}
 				whisper.postEvent(&envelope, true)
+				whisper.traceEnvelope(&envelope, false, p2pSource, p)
 			}
 		case p2pRequestCode:
 			// Must be processed if mail server is implemented. Otherwise ignore.
@@ -883,6 +892,22 @@ func (whisper *Whisper) add(envelope *Envelope, isP2P bool) (bool, error) {
 	return true, nil
 }
 
+// traceEnvelope collects basic metadata about an envelope and sender peer.
+func (whisper *Whisper) traceEnvelope(envelope *Envelope, isNew bool, source envelopeSource, peer *Peer) {
+	if whisper.envelopeTracer == nil {
+		return
+	}
+
+	whisper.envelopeTracer.Trace(&EnvelopeMeta{
+		Hash:   envelope.Hash().String(),
+		Topic:  BytesToTopic(envelope.Topic[:]),
+		Size:   uint32(envelope.size()),
+		Source: source,
+		IsNew:  isNew,
+		Peer:   peer.peer.Info().ID,
+	})
+}
+
 // postEvent queues the message for further processing.
 func (whisper *Whisper) postEvent(envelope *Envelope, isP2P bool) {
 	if isP2P {