diff --git a/src/main/java/com/datadoghq/trace/Example.java b/src/main/java/com/datadoghq/trace/Example.java
new file mode 100644
index 0000000000..f712655fed
--- /dev/null
+++ b/src/main/java/com/datadoghq/trace/Example.java
@@ -0,0 +1,38 @@
+package com.datadoghq.trace;
+
+
+import com.datadoghq.trace.impl.DDTags;
+import com.datadoghq.trace.writer.impl.DDAgentWriter;
+import io.opentracing.Span;
+import io.opentracing.Tracer;
+
+public class Example {
+
+    public static void main(String[] args) {
+
+
+        Tracer tracer = new com.datadoghq.trace.impl.Tracer();
+        Writer writer = new DDAgentWriter();
+
+        Span parent = tracer
+                .buildSpan("hello-world")
+                .withTag(DDTags.SERVICE.getKey(), "service-name")
+                .start();
+
+        parent.setBaggageItem("a-baggage", "value");
+        parent.finish();
+
+        Span child = tracer
+                .buildSpan("hello-world")
+                .asChildOf(parent)
+                .start();
+
+        child.finish();
+
+        writer.write(parent);
+        writer.write(child);
+
+        writer.close();
+
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/com/datadoghq/trace/impl/DDSpan.java b/src/main/java/com/datadoghq/trace/impl/DDSpan.java
index 409a3ec908..38c931c294 100644
--- a/src/main/java/com/datadoghq/trace/impl/DDSpan.java
+++ b/src/main/java/com/datadoghq/trace/impl/DDSpan.java
@@ -12,7 +12,7 @@ public class DDSpan implements io.opentracing.Span {
     private final String operationName;
     private Map<String, Object> tags;
     private long startTime;
-    private long durationMilliseconds;
+    private long durationNano;
     private final DDSpanContext context;
 
     DDSpan(
@@ -24,7 +24,7 @@ public class DDSpan implements io.opentracing.Span {
         this.tracer = tracer;
         this.operationName = operationName;
         this.tags = tags;
-        this.startTime = timestamp.orElse(System.currentTimeMillis());
+        this.startTime = timestamp.orElse(System.nanoTime());
         this.context = context;
     }
 
@@ -33,27 +33,32 @@ public class DDSpan implements io.opentracing.Span {
     }
 
     public void finish() {
-
+        this.durationNano = System.nanoTime() - startTime;
     }
 
-    public void finish(long l) {
-
+    public void finish(long nano) {
+        this.durationNano = nano;
     }
 
     public void close() {
-
+        this.finish();
     }
 
-    public io.opentracing.Span setTag(String s, String s1) {
-        return null;
+    public io.opentracing.Span setTag(String tag, String value) {
+        return this.setTag(tag, value);
     }
 
-    public io.opentracing.Span setTag(String s, boolean b) {
-        return null;
+    public io.opentracing.Span setTag(String tag, boolean value) {
+        return this.setTag(tag, value);
     }
 
-    public io.opentracing.Span setTag(String s, Number number) {
-        return null;
+    public io.opentracing.Span setTag(String tag, Number value) {
+        return this.setTag(tag, (Object) value);
+    }
+
+    private io.opentracing.Span setTag(String tag, Object value) {
+        this.tags.put(tag, value);
+        return this;
     }
 
     public io.opentracing.Span log(Map<String, ?> map) {
@@ -105,8 +110,8 @@ public class DDSpan implements io.opentracing.Span {
         return startTime;
     }
 
-    public DDSpanContext getContext(){
-    	return context;
+    public DDSpanContext getContext() {
+        return context;
     }
 
     public DDSpanContext DDContext() {
diff --git a/src/main/java/com/datadoghq/trace/writer/impl/DDAgentWriter.java b/src/main/java/com/datadoghq/trace/writer/impl/DDAgentWriter.java
index 5e407e2761..71e1fa453a 100644
--- a/src/main/java/com/datadoghq/trace/writer/impl/DDAgentWriter.java
+++ b/src/main/java/com/datadoghq/trace/writer/impl/DDAgentWriter.java
@@ -59,6 +59,7 @@ public class DDAgentWriter implements Writer {
 					commandQueue.drainTo(spans, DEFAULT_BATCH_SIZE);
 					
 					//Then write to the agent
+					System.out.println(spans);
 				} catch (InterruptedException e) {
 					// TODO Auto-generated catch block
 					// FIXME proper logging
diff --git a/src/test/java/com/datadoghq/trace/impl/DDSpanBuilderTest.java b/src/test/java/com/datadoghq/trace/impl/DDSpanBuilderTest.java
index e6e1aa8145..be55751853 100644
--- a/src/test/java/com/datadoghq/trace/impl/DDSpanBuilderTest.java
+++ b/src/test/java/com/datadoghq/trace/impl/DDSpanBuilderTest.java
@@ -14,7 +14,7 @@ import static org.mockito.Mockito.when;
 
 public class DDSpanBuilderTest {
 
-    Tracer tracer;
+    private Tracer tracer;
 
     @Before
     public void setUp() throws Exception {
@@ -72,7 +72,7 @@ public class DDSpanBuilderTest {
     @Test
     public void shouldBuildSpanTimestampInMilli() {
 
-        final long expectedTimestamp = 487517802L * 1000;
+        final long expectedTimestamp = 487517802L;
         final String expectedName = "fakeName";
 
         DDSpan span = (DDSpan) tracer
@@ -83,13 +83,13 @@ public class DDSpanBuilderTest {
         assertThat(span.getStartTime()).isEqualTo(expectedTimestamp);
 
         // auto-timestamp in nanoseconds
-        long tick = System.currentTimeMillis();
+        long tick = System.nanoTime();
         span = (DDSpan) tracer
                 .buildSpan(expectedName)
                 .start();
 
         // between now and now + 100ms
-        assertThat(span.getStartTime()).isBetween(tick, tick + 100);
+        assertThat(span.getStartTime()).isBetween(tick, tick + 100 * 1000);
 
     }
 
@@ -172,10 +172,6 @@ public class DDSpanBuilderTest {
         final String expectedBaggageItemKey = "fakeKey";
         final String expectedBaggageItemValue = "fakeValue";
 
-        Map<String, String> baggage = new HashMap<String, String>() {{
-            put("service", expectedServiceName);
-        }};
-
         DDSpan parent = (DDSpan) tracer
                 .buildSpan(expectedName)
                 .withTag(DDTags.SERVICE.getKey(), expectedServiceName)