diff --git a/cmd/crawl/main.go b/cmd/crawl/main.go
index 9762ff8..83177e7 100644
--- a/cmd/crawl/main.go
+++ b/cmd/crawl/main.go
@@ -39,8 +39,9 @@ func main() {
 		panic(err)
 	}
 
-	events := make(chan *nostr.Event, config.EventsCapacity)
-	pubkeys := make(chan string, config.PubkeysCapacity)
+	db := redb.New(&redis.Options{
+		Addr: config.RedisAddress,
+	})
 
 	store, err := store.New(
 		config.SQLiteURL,
@@ -50,86 +51,96 @@ func main() {
 		panic(err)
 	}
 
-	db := redb.New(&redis.Options{Addr: config.RedisAddress})
+	recorderQueue := make(chan *nostr.Event, config.EventsCapacity)
+	engineQueue := make(chan *nostr.Event, config.EventsCapacity)
+	fetcherQueue := make(chan string, config.PubkeysCapacity)
+
 	nodes, err := db.NodeCount(ctx)
 	if err != nil {
 		panic(err)
 	}
 
 	if nodes == 0 {
-		if len(config.InitPubkeys) == 0 {
-			panic("init pubkeys are empty: impossible to initialize")
+		if err := initGraph(ctx, db, config.InitPubkeys); err != nil {
+			panic(err)
 		}
 
-		log.Println("initialize from empty database...")
-
-		initNodes := make([]graph.ID, len(config.InitPubkeys))
-		for i, pk := range config.InitPubkeys {
-			initNodes[i], err = db.AddNode(ctx, pk)
-			if err != nil {
-				panic(err)
-			}
-
-			pubkeys <- pk // add to queue
+		for _, pk := range config.InitPubkeys {
+			fetcherQueue <- pk
 		}
-
-		for _, node := range initNodes {
-			if err := pipe.Promote(db, node); err != nil {
-				panic(err)
-			}
-		}
-		log.Printf("correctly added %d init pubkeys", len(config.InitPubkeys))
 	}
 
 	if config.PrintStats {
-		go printStats(ctx, events, pubkeys)
+		go printStats(ctx, recorderQueue, engineQueue, fetcherQueue)
 	}
 
 	var producers sync.WaitGroup
 	var consumers sync.WaitGroup
 
-	producers.Add(3)
+	producers.Add(4)
 	go func() {
 		defer producers.Done()
-		pipe.Firehose(ctx, config.Firehose, db, enqueue(events))
+		pipe.Firehose(ctx, config.Firehose, db, pipe.Send(recorderQueue))
 	}()
 
 	go func() {
 		defer producers.Done()
-		pipe.Fetcher(ctx, config.Fetcher, pubkeys, enqueue(events))
+		pipe.Recorder(ctx, db, recorderQueue, pipe.Send(engineQueue))
 	}()
 
 	go func() {
 		defer producers.Done()
-		pipe.Arbiter(ctx, config.Arbiter, db, enqueue(pubkeys))
-		close(pubkeys) // Arbiter is the only pubkey producer
+		pipe.Fetcher(ctx, config.Fetcher, fetcherQueue, pipe.Send(engineQueue))
+	}()
+
+	go func() {
+		defer producers.Done()
+		pipe.Arbiter(ctx, config.Arbiter, db, pipe.Send(fetcherQueue))
+		close(fetcherQueue) // Arbiter is the only pubkey producer
 	}()
 
 	consumers.Add(1)
 	go func() {
 		defer consumers.Done()
-		pipe.Engine(ctx, config.Engine, store, db, events)
+		pipe.Engine(ctx, config.Engine, store, db, engineQueue)
 	}()
 
 	producers.Wait()
-	close(events)
-
+	close(engineQueue)
 	consumers.Wait()
 }
 
-// enqueue things into the specified channel or return an error if full.
-func enqueue[T any](queue chan T) func(t T) error {
-	return func(t T) error {
-		select {
-		case queue <- t:
-			return nil
-		default:
-			return fmt.Errorf("channel is full, dropping %v", t)
+func initGraph(ctx context.Context, db redb.RedisDB, pubkeys []string) error {
+	if len(pubkeys) == 0 {
+		panic("init pubkeys are empty: impossible to initialize")
+	}
+	log.Println("initialize from empty database...")
+
+	var initNodes = make([]graph.ID, len(pubkeys))
+	var err error
+
+	for i, pk := range pubkeys {
+		initNodes[i], err = db.AddNode(ctx, pk)
+		if err != nil {
+			panic(err)
 		}
 	}
+
+	for _, node := range initNodes {
+		if err := pipe.Promote(db, node); err != nil {
+			panic(err)
+		}
+	}
+
+	log.Printf("correctly added %d init pubkeys", len(pubkeys))
+	return nil
 }
 
-func printStats(ctx context.Context, events chan *nostr.Event, pubkeys chan string) {
+func printStats(
+	ctx context.Context,
+	recorderQueue, engineQueue chan *nostr.Event,
+	fetcherQueue chan string,
+) {
 	filename := "stats.log"
 	file, err := os.OpenFile(filename, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0644)
 	if err != nil {
@@ -153,8 +164,9 @@ func printStats(ctx context.Context, events chan *nostr.Event, pubkeys chan stri
 			runtime.ReadMemStats(memStats)
 
 			log.Println("---------------------------------------")
-			log.Printf("events queue: %d/%d\n", len(events), cap(events))
-			log.Printf("pubkeys queue: %d/%d\n", len(pubkeys), cap(pubkeys))
+			log.Printf("Recorder queue: %d/%d\n", len(recorderQueue), cap(recorderQueue))
+			log.Printf("Engine queue: %d/%d\n", len(engineQueue), cap(engineQueue))
+			log.Printf("Fetcher queue: %d/%d\n", len(fetcherQueue), cap(fetcherQueue))
 			log.Printf("walks tracker: %v\n", pipe.WalksTracker.Load())
 			log.Printf("goroutines: %d\n", goroutines)
 			log.Printf("memory usage: %.2f MB\n", float64(memStats.Alloc)/(1024*1024))