diff --git a/src/main/java/com/onthegomap/flatmap/CommonParams.java b/src/main/java/com/onthegomap/flatmap/CommonParams.java
index 36633329..57204432 100644
--- a/src/main/java/com/onthegomap/flatmap/CommonParams.java
+++ b/src/main/java/com/onthegomap/flatmap/CommonParams.java
@@ -25,6 +25,10 @@ public record CommonParams(
     }
   }
 
+  public static CommonParams defaultParams() {
+    return from(new Arguments(new String[]{}));
+  }
+
   public static CommonParams from(Arguments arguments) {
     return from(arguments, BoundsProvider.WORLD);
   }
diff --git a/src/main/java/com/onthegomap/flatmap/OpenMapTilesMain.java b/src/main/java/com/onthegomap/flatmap/OpenMapTilesMain.java
index 8f2d7b38..007a68cc 100644
--- a/src/main/java/com/onthegomap/flatmap/OpenMapTilesMain.java
+++ b/src/main/java/com/onthegomap/flatmap/OpenMapTilesMain.java
@@ -13,7 +13,6 @@ import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.List;
-import java.util.concurrent.atomic.AtomicLong;
 import org.apache.commons.io.FileUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -85,10 +84,9 @@ public class OpenMapTilesMain {
         .process("natural_earth", renderer, featureMap, config)
     );
 
-    AtomicLong featureCount = new AtomicLong(0);
     try (var osmReader = new OpenStreetMapReader(osmInputFile, nodeLocations, profile, stats)) {
       stats.time("osm_pass1", () -> osmReader.pass1(config));
-      stats.time("osm_pass2", () -> featureCount.set(osmReader.pass2(renderer, featureMap, config)));
+      stats.time("osm_pass2", () -> osmReader.pass2(renderer, featureMap, config));
     }
 
     LOGGER.info("Deleting node.db to make room for mbtiles");
@@ -96,8 +94,7 @@ public class OpenMapTilesMain {
     Files.delete(nodeDb);
 
     stats.time("sort", featureDb::sort);
-    stats
-      .time("mbtiles", () -> MbtilesWriter.writeOutput(featureCount.get(), featureMap, output, profile, config, stats));
+    stats.time("mbtiles", () -> MbtilesWriter.writeOutput(featureMap, output, profile, config, stats));
 
     stats.stopTimer("import");
 
diff --git a/src/main/java/com/onthegomap/flatmap/collections/ExternalMergeSort.java b/src/main/java/com/onthegomap/flatmap/collections/ExternalMergeSort.java
index 273e5706..e03b943d 100644
--- a/src/main/java/com/onthegomap/flatmap/collections/ExternalMergeSort.java
+++ b/src/main/java/com/onthegomap/flatmap/collections/ExternalMergeSort.java
@@ -37,6 +37,7 @@ class ExternalMergeSort implements FeatureSort {
   private final Stats stats;
   private final int chunkSizeLimit;
   private final int workers;
+  private final AtomicLong features = new AtomicLong(0);
 
   private final List<Chunk> chunks = new ArrayList<>();
   private Chunk current;
@@ -78,6 +79,7 @@ class ExternalMergeSort implements FeatureSort {
   public void add(Entry item) {
     try {
       assert !sorted;
+      features.incrementAndGet();
       current.add(item);
       if (current.bytesInMemory > chunkSizeLimit) {
         newChunk();
@@ -148,6 +150,11 @@ class ExternalMergeSort implements FeatureSort {
       "s sort:" + Duration.ofNanos(sorting.get()).toSeconds() + "s");
   }
 
+  @Override
+  public long size() {
+    return features.get();
+  }
+
   @NotNull
   @Override
   public Iterator<Entry> iterator() {
@@ -187,7 +194,7 @@ class ExternalMergeSort implements FeatureSort {
     chunks.add(current = new Chunk(chunkPath));
   }
 
-  class Chunk implements Closeable {
+  private static class Chunk implements Closeable {
 
     private final Path path;
     private final DataOutputStream outputStream;
@@ -273,7 +280,7 @@ class ExternalMergeSort implements FeatureSort {
     }
   }
 
-  class PeekableScanner implements Closeable, Comparable<PeekableScanner>, Iterator<Entry> {
+  private static class PeekableScanner implements Closeable, Comparable<PeekableScanner>, Iterator<Entry> {
 
     private final int count;
     private int read = 0;
diff --git a/src/main/java/com/onthegomap/flatmap/collections/FeatureGroup.java b/src/main/java/com/onthegomap/flatmap/collections/FeatureGroup.java
index 0a504395..23d344c1 100644
--- a/src/main/java/com/onthegomap/flatmap/collections/FeatureGroup.java
+++ b/src/main/java/com/onthegomap/flatmap/collections/FeatureGroup.java
@@ -71,6 +71,10 @@ public record FeatureGroup(FeatureSort sorter, Profile profile, CommonStringEnco
     }
   }
 
+  public long numFeatures() {
+    return sorter.size();
+  }
+
   public FeatureSort.Entry encode(RenderedFeature feature) {
     return new FeatureSort.Entry(
       encodeSortKey(feature),
@@ -235,7 +239,7 @@ public record FeatureGroup(FeatureSort sorter, Profile profile, CommonStringEnco
     }
 
     public long getNumFeatures() {
-      return 0;
+      return entries.size();
     }
 
     public TileCoord coord() {
diff --git a/src/main/java/com/onthegomap/flatmap/collections/FeatureSort.java b/src/main/java/com/onthegomap/flatmap/collections/FeatureSort.java
index 09f2b886..be012197 100644
--- a/src/main/java/com/onthegomap/flatmap/collections/FeatureSort.java
+++ b/src/main/java/com/onthegomap/flatmap/collections/FeatureSort.java
@@ -4,6 +4,8 @@ import com.onthegomap.flatmap.monitoring.Stats;
 import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Comparator;
+import java.util.Iterator;
 import java.util.List;
 import org.jetbrains.annotations.NotNull;
 
@@ -17,8 +19,41 @@ public interface FeatureSort extends Iterable<FeatureSort.Entry> {
     return new ExternalMergeSort(dir, workers, chunkSizeLimit, stats);
   }
 
+  static FeatureSort newInMemory() {
+    List<Entry> list = new ArrayList<>();
+    return new FeatureSort() {
+      @Override
+      public void sort() {
+        list.sort(Comparator.naturalOrder());
+      }
+
+      @Override
+      public long size() {
+        return list.size();
+      }
+
+      @Override
+      public void add(Entry newEntry) {
+        list.add(newEntry);
+      }
+
+      @Override
+      public long getStorageSize() {
+        return 0;
+      }
+
+      @NotNull
+      @Override
+      public Iterator<Entry> iterator() {
+        return list.iterator();
+      }
+    };
+  }
+
   void sort();
 
+  long size();
+
   default List<Entry> toList() {
     List<Entry> list = new ArrayList<>();
     for (Entry entry : this) {
diff --git a/src/main/java/com/onthegomap/flatmap/read/OpenStreetMapReader.java b/src/main/java/com/onthegomap/flatmap/read/OpenStreetMapReader.java
index 3ddf7446..e56aa69e 100644
--- a/src/main/java/com/onthegomap/flatmap/read/OpenStreetMapReader.java
+++ b/src/main/java/com/onthegomap/flatmap/read/OpenStreetMapReader.java
@@ -107,13 +107,12 @@ public class OpenStreetMapReader implements Closeable {
     topology.awaitAndLog(loggers, config.logInterval());
   }
 
-  public long pass2(FeatureRenderer renderer, FeatureGroup writer, CommonParams config) {
+  public void pass2(FeatureRenderer renderer, FeatureGroup writer, CommonParams config) {
     int readerThreads = Math.max(config.threads() / 4, 1);
     int processThreads = config.threads() - 1;
     AtomicLong nodesProcessed = new AtomicLong(0);
     AtomicLong waysProcessed = new AtomicLong(0);
     AtomicLong relsProcessed = new AtomicLong(0);
-    AtomicLong featuresWritten = new AtomicLong(0);
     CountDownLatch waysDone = new CountDownLatch(processThreads);
 
     var topology = Topology.start("osm_pass2", stats)
@@ -153,17 +152,14 @@ public class OpenStreetMapReader implements Closeable {
         // just in case a worker skipped over all relations
         waysDone.countDown();
       }).addBuffer("feature_queue", 50_000, 1_000)
-      .sinkToConsumer("write", 1, (item) -> {
-        featuresWritten.incrementAndGet();
-        writer.accept(item);
-      });
+      .sinkToConsumer("write", 1, writer);
 
     var logger = new ProgressLoggers("osm_pass2")
       .addRatePercentCounter("nodes", TOTAL_NODES.get(), nodesProcessed)
       .addFileSize(nodeDb.filePath())
       .addRatePercentCounter("ways", TOTAL_WAYS.get(), waysProcessed)
       .addRatePercentCounter("rels", TOTAL_RELATIONS.get(), relsProcessed)
-      .addRateCounter("features", featuresWritten)
+      .addRateCounter("features", () -> writer.sorter().size())
       .addFileSize(writer::getStorageSize)
       .addProcessStats()
       .addInMemoryObject("hppc", this::getBigObjectSizeBytes)
@@ -171,8 +167,6 @@ public class OpenStreetMapReader implements Closeable {
       .addTopologyStats(topology);
 
     topology.awaitAndLog(logger, config.logInterval());
-
-    return featuresWritten.get();
   }
 
   private long getBigObjectSizeBytes() {
diff --git a/src/main/java/com/onthegomap/flatmap/write/Mbtiles.java b/src/main/java/com/onthegomap/flatmap/write/Mbtiles.java
index 0c080ca0..4ebbb1bf 100644
--- a/src/main/java/com/onthegomap/flatmap/write/Mbtiles.java
+++ b/src/main/java/com/onthegomap/flatmap/write/Mbtiles.java
@@ -26,6 +26,7 @@ import java.util.OptionalInt;
 import java.util.TreeMap;
 import java.util.stream.Collectors;
 import java.util.stream.DoubleStream;
+import org.jetbrains.annotations.NotNull;
 import org.locationtech.jts.geom.Coordinate;
 import org.locationtech.jts.geom.Envelope;
 import org.slf4j.Logger;
@@ -377,7 +378,7 @@ public record Mbtiles(Connection connection) implements Closeable {
     }
   }
 
-  public static record TileEntry(TileCoord tile, byte[] bytes) {
+  public static record TileEntry(TileCoord tile, byte[] bytes) implements Comparable<TileEntry> {
 
     @Override
     public boolean equals(Object o) {
@@ -410,5 +411,10 @@ public record Mbtiles(Connection connection) implements Closeable {
         ", bytes=" + Arrays.toString(bytes) +
         '}';
     }
+
+    @Override
+    public int compareTo(@NotNull TileEntry o) {
+      return tile.compareTo(o.tile);
+    }
   }
 }
diff --git a/src/main/java/com/onthegomap/flatmap/write/MbtilesWriter.java b/src/main/java/com/onthegomap/flatmap/write/MbtilesWriter.java
index 9b3875b6..0d54df53 100644
--- a/src/main/java/com/onthegomap/flatmap/write/MbtilesWriter.java
+++ b/src/main/java/com/onthegomap/flatmap/write/MbtilesWriter.java
@@ -4,7 +4,6 @@ import com.onthegomap.flatmap.CommonParams;
 import com.onthegomap.flatmap.Profile;
 import com.onthegomap.flatmap.VectorTileEncoder;
 import com.onthegomap.flatmap.collections.FeatureGroup;
-import com.onthegomap.flatmap.geo.TileCoord;
 import com.onthegomap.flatmap.monitoring.ProgressLoggers;
 import com.onthegomap.flatmap.monitoring.Stats;
 import com.onthegomap.flatmap.worker.Topology;
@@ -31,19 +30,15 @@ public class MbtilesWriter {
   private final Profile profile;
   private final Stats stats;
 
-  private MbtilesWriter(Path path, CommonParams config, Profile profile, Stats stats) {
+  MbtilesWriter(Path path, CommonParams config, Profile profile, Stats stats) {
     this.path = path;
     this.config = config;
     this.profile = profile;
     this.stats = stats;
   }
 
-  private static record RenderedTile(TileCoord tile, byte[] contents) {
-
-  }
-
-  public static void writeOutput(long featureCount, FeatureGroup features, Path output, Profile profile,
-    CommonParams config, Stats stats) {
+  public static void writeOutput(FeatureGroup features, Path output, Profile profile, CommonParams config,
+    Stats stats) {
     try {
       Files.deleteIfExists(output);
     } catch (IOException e) {
@@ -59,7 +54,7 @@ public class MbtilesWriter {
       .sinkTo("writer", 1, writer::tileWriter);
 
     var loggers = new ProgressLoggers("mbtiles")
-      .addRatePercentCounter("features", featureCount, writer.featuresProcessed)
+      .addRatePercentCounter("features", features.numFeatures(), writer.featuresProcessed)
       .addRateCounter("tiles", writer.tiles)
       .addFileSize(output)
       .add(" features ").addFileSize(features::getStorageSize)
@@ -69,7 +64,7 @@ public class MbtilesWriter {
     topology.awaitAndLog(loggers, config.logInterval());
   }
 
-  public void tileEncoder(Supplier<FeatureGroup.TileFeatures> prev, Consumer<RenderedTile> next) throws Exception {
+  void tileEncoder(Supplier<FeatureGroup.TileFeatures> prev, Consumer<Mbtiles.TileEntry> next) throws IOException {
     FeatureGroup.TileFeatures tileFeatures, last = null;
     byte[] lastBytes = null, lastEncoded = null;
     while ((tileFeatures = prev.get()) != null) {
@@ -91,11 +86,11 @@ public class MbtilesWriter {
         }
       }
       stats.encodedTile(tileFeatures.coord().z(), encoded.length);
-      next.accept(new RenderedTile(tileFeatures.coord(), bytes));
+      next.accept(new Mbtiles.TileEntry(tileFeatures.coord(), bytes));
     }
   }
 
-  private void tileWriter(Supplier<RenderedTile> tiles) throws Exception {
+  private void tileWriter(Supplier<Mbtiles.TileEntry> tiles) throws Exception {
     try (Mbtiles db = Mbtiles.newFileDatabase(path)) {
       db.setupSchema();
       db.tuneForWrites();
@@ -118,9 +113,9 @@ public class MbtilesWriter {
         .setJson(stats.getTileStats());
 
       try (var batchedWriter = db.newBatchedTileWriter()) {
-        RenderedTile tile;
+        Mbtiles.TileEntry tile;
         while ((tile = tiles.get()) != null) {
-          batchedWriter.write(tile.tile(), tile.contents);
+          batchedWriter.write(tile.tile(), tile.bytes());
         }
       }
 
diff --git a/src/test/java/com/onthegomap/flatmap/collections/FeatureGroupTest.java b/src/test/java/com/onthegomap/flatmap/collections/FeatureGroupTest.java
index e44bb358..4d123b37 100644
--- a/src/test/java/com/onthegomap/flatmap/collections/FeatureGroupTest.java
+++ b/src/test/java/com/onthegomap/flatmap/collections/FeatureGroupTest.java
@@ -12,13 +12,10 @@ import com.onthegomap.flatmap.VectorTileEncoder;
 import com.onthegomap.flatmap.geo.TileCoord;
 import java.util.ArrayList;
 import java.util.Collections;
-import java.util.Comparator;
-import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.TreeMap;
-import org.jetbrains.annotations.NotNull;
 import org.junit.jupiter.api.DynamicTest;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.TestFactory;
@@ -28,29 +25,7 @@ import org.locationtech.jts.geom.Geometry;
 
 public class FeatureGroupTest {
 
-  private final List<FeatureSort.Entry> list = new ArrayList<>();
-  private final FeatureSort sorter = new FeatureSort() {
-    @Override
-    public void sort() {
-      list.sort(Comparator.naturalOrder());
-    }
-
-    @Override
-    public void add(Entry newEntry) {
-      list.add(newEntry);
-    }
-
-    @Override
-    public long getStorageSize() {
-      return 0;
-    }
-
-    @NotNull
-    @Override
-    public Iterator<Entry> iterator() {
-      return list.iterator();
-    }
-  };
+  private final FeatureSort sorter = FeatureSort.newInMemory();
   private FeatureGroup features = new FeatureGroup(sorter, new Profile.NullProfile());
 
   @Test
diff --git a/src/test/java/com/onthegomap/flatmap/write/MbtilesTest.java b/src/test/java/com/onthegomap/flatmap/write/MbtilesTest.java
index 28243ae2..33cac55a 100644
--- a/src/test/java/com/onthegomap/flatmap/write/MbtilesTest.java
+++ b/src/test/java/com/onthegomap/flatmap/write/MbtilesTest.java
@@ -6,13 +6,11 @@ import com.fasterxml.jackson.databind.ObjectMapper;
 import com.onthegomap.flatmap.geo.GeoUtils;
 import com.onthegomap.flatmap.geo.TileCoord;
 import java.io.IOException;
-import java.sql.ResultSet;
 import java.sql.SQLException;
-import java.sql.Statement;
-import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;
 import java.util.TreeMap;
+import java.util.TreeSet;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.ValueSource;
@@ -31,7 +29,7 @@ public class MbtilesTest {
       if (!deferIndexCreation) {
         db.addIndex();
       }
-      Set<Mbtiles.TileEntry> expected = new HashSet<>();
+      Set<Mbtiles.TileEntry> expected = new TreeSet<>();
       try (var writer = db.newBatchedTileWriter()) {
         for (int i = 0; i < howMany; i++) {
           var entry = new Mbtiles.TileEntry(TileCoord.ofXYZ(i, i, 14), new byte[]{
@@ -50,7 +48,7 @@ public class MbtilesTest {
       if (optimize) {
         db.vacuumAnalyze();
       }
-      var all = getAll(db);
+      var all = MbtilesTestUtils.getAll(db);
       assertEquals(howMany, all.size());
       assertEquals(expected, all);
     }
@@ -196,22 +194,4 @@ public class MbtilesTest {
       }
       """);
   }
-
-  private static Set<Mbtiles.TileEntry> getAll(Mbtiles db) throws SQLException {
-    Set<Mbtiles.TileEntry> result = new HashSet<>();
-    try (Statement statement = db.connection().createStatement()) {
-      ResultSet rs = statement.executeQuery("select zoom_level, tile_column, tile_row, tile_data from tiles");
-      while (rs.next()) {
-        result.add(new Mbtiles.TileEntry(
-          TileCoord.ofXYZ(
-            rs.getInt("tile_column"),
-            rs.getInt("tile_row"),
-            rs.getInt("zoom_level")
-          ),
-          rs.getBytes("tile_data")
-        ));
-      }
-    }
-    return result;
-  }
 }
diff --git a/src/test/java/com/onthegomap/flatmap/write/MbtilesTestUtils.java b/src/test/java/com/onthegomap/flatmap/write/MbtilesTestUtils.java
new file mode 100644
index 00000000..4b2a2101
--- /dev/null
+++ b/src/test/java/com/onthegomap/flatmap/write/MbtilesTestUtils.java
@@ -0,0 +1,29 @@
+package com.onthegomap.flatmap.write;
+
+import com.onthegomap.flatmap.geo.TileCoord;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.HashSet;
+import java.util.Set;
+
+public class MbtilesTestUtils {
+
+  static Set<Mbtiles.TileEntry> getAll(Mbtiles db) throws SQLException {
+    Set<Mbtiles.TileEntry> result = new HashSet<>();
+    try (Statement statement = db.connection().createStatement()) {
+      ResultSet rs = statement.executeQuery("select zoom_level, tile_column, tile_row, tile_data from tiles");
+      while (rs.next()) {
+        result.add(new Mbtiles.TileEntry(
+          TileCoord.ofXYZ(
+            rs.getInt("tile_column"),
+            rs.getInt("tile_row"),
+            rs.getInt("zoom_level")
+          ),
+          rs.getBytes("tile_data")
+        ));
+      }
+    }
+    return result;
+  }
+}
diff --git a/src/test/java/com/onthegomap/flatmap/write/MbtilesWriterTest.java b/src/test/java/com/onthegomap/flatmap/write/MbtilesWriterTest.java
deleted file mode 100644
index 1c84f9df..00000000
--- a/src/test/java/com/onthegomap/flatmap/write/MbtilesWriterTest.java
+++ /dev/null
@@ -1,5 +0,0 @@
-package com.onthegomap.flatmap.write;
-
-public class MbtilesWriterTest {
-
-}