diff --git a/README.md b/README.md
index 07753aa..d947cd5 100644
--- a/README.md
+++ b/README.md
@@ -81,13 +81,14 @@ In some cases, attributes in a JSON response can by dynamic (e.g unique id's, da
 ```json
 {
   "defaults": {
+    "Etag": "default-etag-value",
     "updated_at": 0,
     "foo": "foobar"
   }
 }
 ```
 
-When used with `AssertHTTPResponse`, for any response with `Content-Type: application/json`, the key-value pairs in `defaults` will be used to override the JSON response, allowing for consistent snapshot testing.
+When used with `AssertHTTPResponse`, for any response with `Content-Type: application/json`, the key-value pairs in `defaults` will be used to override the JSON response, allowing for consistent snapshot testing. Any HTTP headers will also be override for key matches in `defaults`.
 
 
 ## Using custom `__snapshot__` directory
diff --git a/assert.go b/assert.go
index 355aace..aa18c6f 100644
--- a/assert.go
+++ b/assert.go
@@ -66,10 +66,22 @@ func assertHTTP(t *testing.T, id string, body []byte, isJSON bool) {
 	}
 
 	data := string(body)
+	lines := strings.Split(strings.TrimSpace(data), "\n")
+
+	// empty line identifies the end of the HTTP header
+	for i, line := range lines {
+		if line == "" {
+			break
+		}
+
+		headerItem := strings.Split(line, ":")
+		if def, ok := config.Defaults[headerItem[0]]; ok {
+			lines[i] = fmt.Sprintf("%s: %s", headerItem[0], def)
+		}
+	}
 
 	// If the response body is JSON, indent.
 	if isJSON {
-		lines := strings.Split(strings.TrimSpace(data), "\n")
 		jsonStr := lines[len(lines)-1]
 
 		var jsonIface map[string]interface{}
@@ -90,9 +102,9 @@ func assertHTTP(t *testing.T, id string, body []byte, isJSON bool) {
 			t.Fatal(err)
 		}
 		lines[len(lines)-1] = string(out)
-		data = strings.Join(lines, "\n")
 	}
 
+	data = strings.Join(lines, "\n")
 	createOrUpdateSnapshot(t, id, data)
 }
 
diff --git a/example/__snapshots__/example.snapshot b/example/__snapshots__/example.snapshot
index e9991f2..5a1b26f 100755
--- a/example/__snapshots__/example.snapshot
+++ b/example/__snapshots__/example.snapshot
@@ -2,6 +2,7 @@
 HTTP/1.1 200 OK
 Connection: close
 Content-Type: application/json
+Etag: default-etag-value
 
 {
   "foo": "foobar"
@@ -38,6 +39,7 @@ Hello World.
 HTTP/1.1 200 OK
 Connection: close
 Content-Type: application/json
+Etag: default-etag-value
 
 {
   "post": {
diff --git a/example/abide.json b/example/abide.json
index 4c7fa09..4b428ff 100644
--- a/example/abide.json
+++ b/example/abide.json
@@ -1,5 +1,6 @@
 {
   "defaults": {
+    "Etag": "default-etag-value",
     "updated_at": 0,
     "foo": "foobar"
   }
diff --git a/example/main.go b/example/main.go
index c579635..c3f76eb 100644
--- a/example/main.go
+++ b/example/main.go
@@ -3,6 +3,7 @@ package main
 import (
 	"encoding/json"
 	"net/http"
+	"strconv"
 	"time"
 
 	"github.com/beme/abide/example/models"
@@ -20,6 +21,7 @@ func firstHandler(w http.ResponseWriter, r *http.Request) {
 	}
 
 	w.Header().Set("Content-Type", "application/json")
+	w.Header().Set("Etag", strconv.FormatInt(time.Now().UnixNano(), 10))
 	w.Write(body)
 }
 
@@ -47,6 +49,7 @@ func secondHandler(w http.ResponseWriter, r *http.Request) {
 	}
 
 	w.Header().Set("Content-Type", "application/json")
+	w.Header().Set("Etag", strconv.FormatInt(time.Now().UnixNano(), 10))
 	w.Write(body)
 }