diff --git a/api/server/src/main/java/org/softwareheritage/graph/Graph.java b/api/server/src/main/java/org/softwareheritage/graph/Graph.java
--- a/api/server/src/main/java/org/softwareheritage/graph/Graph.java
+++ b/api/server/src/main/java/org/softwareheritage/graph/Graph.java
@@ -3,7 +3,6 @@
 import java.io.IOException;
 
 import it.unimi.dsi.big.webgraph.BVGraph;
-import it.unimi.dsi.big.webgraph.LazyLongIterator;
 
 import org.softwareheritage.graph.SwhId;
 import org.softwareheritage.graph.backend.NodeIdMap;
@@ -45,16 +44,16 @@
     return graph.numArcs();
   }
 
-  public LazyLongIterator successors(long nodeId) {
-    return graph.successors(nodeId);
+  public long[][] successors(long nodeId) {
+    return graph.successorBigArray(nodeId);
   }
 
   public long outdegree(long nodeId) {
     return graph.outdegree(nodeId);
   }
 
-  public LazyLongIterator predecessors(long nodeId) {
-    return graphTransposed.successors(nodeId);
+  public long[][] predecessors(long nodeId) {
+    return graphTransposed.successorBigArray(nodeId);
   }
 
   public long indegree(long nodeId) {
@@ -65,7 +64,7 @@
     return (useTransposed) ? indegree(nodeId) : outdegree(nodeId);
   }
 
-  public LazyLongIterator neighbors(long nodeId, boolean useTransposed) {
+  public long[][] neighbors(long nodeId, boolean useTransposed) {
     return (useTransposed) ? predecessors(nodeId) : successors(nodeId);
   }
 }
diff --git a/api/server/src/main/java/org/softwareheritage/graph/Neighbors.java b/api/server/src/main/java/org/softwareheritage/graph/Neighbors.java
new file mode 100644
--- /dev/null
+++ b/api/server/src/main/java/org/softwareheritage/graph/Neighbors.java
@@ -0,0 +1,60 @@
+package org.softwareheritage.graph;
+
+import java.util.Iterator;
+
+import it.unimi.dsi.fastutil.longs.LongBigArrays;
+
+import org.softwareheritage.graph.AllowedEdges;
+import org.softwareheritage.graph.Graph;
+import org.softwareheritage.graph.SwhId;
+
+public class Neighbors implements Iterable<Long> {
+  Graph graph;
+  boolean useTransposed;
+  AllowedEdges edges;
+  SwhId src;
+
+  public Neighbors(Graph graph, boolean useTransposed, AllowedEdges edges, SwhId src) {
+    this.graph = graph;
+    this.useTransposed = useTransposed;
+    this.edges = edges;
+    this.src = src;
+  }
+
+  @Override
+  public Iterator<Long> iterator() {
+    return new NeighborsIterator();
+  }
+
+  public class NeighborsIterator implements Iterator<Long> {
+    long nextNeighborIdx;
+    long nbNeighbors;
+    long[][] neighbors;
+
+    public NeighborsIterator() {
+      long srcNodeId = graph.getNodeId(src);
+
+      this.nextNeighborIdx = -1;
+      this.nbNeighbors = graph.degree(srcNodeId, useTransposed);
+      this.neighbors = graph.neighbors(srcNodeId, useTransposed);
+    }
+
+    // Look ahead because with edge restriction not all neighbors are considered
+    public boolean hasNext() {
+      for (long lookAheadIdx = nextNeighborIdx + 1; lookAheadIdx < nbNeighbors; lookAheadIdx++) {
+        long nextNodeId = LongBigArrays.get(neighbors, lookAheadIdx);
+        SwhId nextSwhId = graph.getSwhId(nextNodeId);
+        if (edges.isAllowed(src.getType(), nextSwhId.getType())) {
+          nextNeighborIdx = lookAheadIdx;
+          return true;
+        }
+      }
+      return false;
+    }
+
+    public Long next() {
+      long nextNodeId = LongBigArrays.get(neighbors, nextNeighborIdx);
+      return nextNodeId;
+    }
+  }
+}
diff --git a/api/server/src/main/java/org/softwareheritage/graph/algo/Leaves.java b/api/server/src/main/java/org/softwareheritage/graph/algo/Leaves.java
--- a/api/server/src/main/java/org/softwareheritage/graph/algo/Leaves.java
+++ b/api/server/src/main/java/org/softwareheritage/graph/algo/Leaves.java
@@ -2,12 +2,11 @@
 
 import java.util.ArrayList;
 
-import it.unimi.dsi.big.webgraph.LazyLongIterator;
 import it.unimi.dsi.bits.LongArrayBitVector;
 
 import org.softwareheritage.graph.AllowedEdges;
 import org.softwareheritage.graph.Graph;
-import org.softwareheritage.graph.Node;
+import org.softwareheritage.graph.Neighbors;
 import org.softwareheritage.graph.SwhId;
 
 public class Leaves {
@@ -41,19 +40,11 @@
     visited.set(currentNodeId);
     SwhId currentSwhId = graph.getSwhId(currentNodeId);
 
-    long degree = graph.degree(currentNodeId, useTransposed);
-    LazyLongIterator neighbors = graph.neighbors(currentNodeId, useTransposed);
     long neighborsCnt = 0;
-
-    while (degree-- > 0) {
-      long neighborNodeId = neighbors.nextLong();
-      Node.Type currentNodeType = currentSwhId.getType();
-      Node.Type neighborNodeType = graph.getSwhId(neighborNodeId).getType();
-      if (edges.isAllowed(currentNodeType, neighborNodeType)) {
-        neighborsCnt++;
-        if (!visited.getBoolean(neighborNodeId)) {
-          dfs(neighborNodeId);
-        }
+    for (long neighborNodeId : new Neighbors(graph, useTransposed, edges, currentSwhId)) {
+      neighborsCnt++;
+      if (!visited.getBoolean(neighborNodeId)) {
+        dfs(neighborNodeId);
       }
     }
 
diff --git a/api/server/src/main/java/org/softwareheritage/graph/algo/Neighbors.java b/api/server/src/main/java/org/softwareheritage/graph/algo/Neighbors.java
--- a/api/server/src/main/java/org/softwareheritage/graph/algo/Neighbors.java
+++ b/api/server/src/main/java/org/softwareheritage/graph/algo/Neighbors.java
@@ -2,8 +2,6 @@
 
 import java.util.ArrayList;
 
-import it.unimi.dsi.big.webgraph.LazyLongIterator;
-
 import org.softwareheritage.graph.AllowedEdges;
 import org.softwareheritage.graph.Graph;
 import org.softwareheritage.graph.SwhId;
@@ -33,17 +31,9 @@
   }
 
   private void iterateNeighbors(SwhId swhId) {
-    long nodeId = graph.getNodeId(swhId);
-    long degree = graph.degree(nodeId, useTransposed);
-    LazyLongIterator neighborsNodeIds = graph.neighbors(nodeId, useTransposed);
-
-    while (degree-- > 0) {
-      long neighborNodeId = neighborsNodeIds.nextLong();
-      SwhId neighborSwhId = graph.getSwhId(neighborNodeId);
-      if (edges.isAllowed(swhId.getType(), neighborSwhId.getType())) {
-        neighbors.add(neighborSwhId);
-      }
+    // TEMPORARY FIX: Avoid import naming problem with Neighbors
+    for (long neighborNodeId : new org.softwareheritage.graph.Neighbors(graph, useTransposed, edges, swhId)) {
+      neighbors.add(graph.getSwhId(neighborNodeId));
     }
   }
 }
-
diff --git a/api/server/src/main/java/org/softwareheritage/graph/algo/Visit.java b/api/server/src/main/java/org/softwareheritage/graph/algo/Visit.java
--- a/api/server/src/main/java/org/softwareheritage/graph/algo/Visit.java
+++ b/api/server/src/main/java/org/softwareheritage/graph/algo/Visit.java
@@ -4,12 +4,11 @@
 import java.util.LinkedHashSet;
 import java.util.Stack;
 
-import it.unimi.dsi.big.webgraph.LazyLongIterator;
 import it.unimi.dsi.bits.LongArrayBitVector;
 
 import org.softwareheritage.graph.AllowedEdges;
 import org.softwareheritage.graph.Graph;
-import org.softwareheritage.graph.Node;
+import org.softwareheritage.graph.Neighbors;
 import org.softwareheritage.graph.SwhId;
 import org.softwareheritage.graph.SwhPath;
 
@@ -56,21 +55,14 @@
   }
 
   private void dfs(long currentNodeId) {
-    nodes.add(graph.getSwhId(currentNodeId));
+    SwhId currentSwhId = graph.getSwhId(currentNodeId);
+    nodes.add(currentSwhId);
     currentPath.push(currentNodeId);
 
-    long degree = graph.degree(currentNodeId, useTransposed);
-    LazyLongIterator neighbors = graph.neighbors(currentNodeId, useTransposed);
     long visitedNeighbors = 0;
-
-    while (degree-- > 0) {
-      long neighborNodeId = neighbors.nextLong();
-      Node.Type currentNodeType = graph.getSwhId(currentNodeId).getType();
-      Node.Type neighborNodeType = graph.getSwhId(neighborNodeId).getType();
-      if (edges.isAllowed(currentNodeType, neighborNodeType)) {
+    for (long neighborNodeId : new Neighbors(graph, useTransposed, edges, currentSwhId)) {
         dfs(neighborNodeId);
         visitedNeighbors++;
-      }
     }
 
     if (visitedNeighbors == 0) {
@@ -85,18 +77,12 @@
   }
 
   private void dfsOutputOnlyNodes(long currentNodeId) {
-    nodes.add(graph.getSwhId(currentNodeId));
+    SwhId currentSwhId = graph.getSwhId(currentNodeId);
+    nodes.add(currentSwhId);
     visited.set(currentNodeId);
 
-    long degree = graph.degree(currentNodeId, useTransposed);
-    LazyLongIterator neighbors = graph.neighbors(currentNodeId, useTransposed);
-
-    while (degree-- > 0) {
-      long neighborNodeId = neighbors.nextLong();
-      Node.Type currentNodeType = graph.getSwhId(currentNodeId).getType();
-      Node.Type neighborNodeType = graph.getSwhId(neighborNodeId).getType();
-      if (!visited.getBoolean(neighborNodeId)
-          && edges.isAllowed(currentNodeType, neighborNodeType)) {
+    for (long neighborNodeId : new Neighbors(graph, useTransposed, edges, currentSwhId)) {
+      if (!visited.getBoolean(neighborNodeId)) {
         dfsOutputOnlyNodes(neighborNodeId);
       }
     }
diff --git a/api/server/src/main/java/org/softwareheritage/graph/algo/Walk.java b/api/server/src/main/java/org/softwareheritage/graph/algo/Walk.java
--- a/api/server/src/main/java/org/softwareheritage/graph/algo/Walk.java
+++ b/api/server/src/main/java/org/softwareheritage/graph/algo/Walk.java
@@ -4,12 +4,12 @@
 import java.util.Queue;
 import java.util.LinkedList;
 
-import it.unimi.dsi.big.webgraph.LazyLongIterator;
 import it.unimi.dsi.bits.LongArrayBitVector;
 import it.unimi.dsi.fastutil.longs.LongBigArrays;
 
 import org.softwareheritage.graph.AllowedEdges;
 import org.softwareheritage.graph.Graph;
+import org.softwareheritage.graph.Neighbors;
 import org.softwareheritage.graph.Node;
 import org.softwareheritage.graph.SwhId;
 import org.softwareheritage.graph.SwhPath;
@@ -81,14 +81,8 @@
         return currentNodeId;
       }
 
-      long degree = graph.degree(currentNodeId, useTransposed);
-      LazyLongIterator neighbors = graph.neighbors(currentNodeId, useTransposed);
-
-      while (degree-- > 0) {
-        long neighborNodeId = neighbors.nextLong();
-        SwhId neighborSwhId = graph.getSwhId(neighborNodeId);
-        if (!visited.getBoolean(neighborNodeId)
-            && edges.isAllowed(currentSwhId.getType(), neighborSwhId.getType())) {
+      for (long neighborNodeId : new Neighbors(graph, useTransposed, edges, currentSwhId)) {
+        if (!visited.getBoolean(neighborNodeId)) {
           stack.push(neighborNodeId);
           visited.set(neighborNodeId);
           LongBigArrays.set(nodeParent, neighborNodeId, currentNodeId);
@@ -113,14 +107,8 @@
         return currentNodeId;
       }
 
-      long degree = graph.degree(currentNodeId, useTransposed);
-      LazyLongIterator neighbors = graph.neighbors(currentNodeId, useTransposed);
-
-      while (degree-- > 0) {
-        long neighborNodeId = neighbors.nextLong();
-        SwhId neighborSwhId = graph.getSwhId(neighborNodeId);
-        if (!visited.getBoolean(neighborNodeId)
-            && edges.isAllowed(currentSwhId.getType(), neighborSwhId.getType())) {
+      for (long neighborNodeId : new Neighbors(graph, useTransposed, edges, currentSwhId)) {
+        if (!visited.getBoolean(neighborNodeId)) {
           queue.add(neighborNodeId);
           visited.set(neighborNodeId);
           LongBigArrays.set(nodeParent, neighborNodeId, currentNodeId);