diff --git a/app/mf/mention.go b/app/mf/mention.go
index 03a8f98..9e1a0a8 100644
--- a/app/mf/mention.go
+++ b/app/mf/mention.go
@@ -31,6 +31,8 @@ func (wm Mention) Domain() string {
 	return rest.Domain(wm.Target)
 }
 
+// Key returns a unique string representation of the mention for use in storage.
+// TODO Profiling indicated that md5() consumes a lot of CPU power, so this could be replaced with db migration.
 func (wm Mention) Key() string {
 	return fmt.Sprintf("%x", md5.Sum([]byte("source="+wm.Source+",target="+wm.Target)))
 }
diff --git a/app/mf/microformats.go b/app/mf/microformats.go
index a8de66a..cfcd18d 100644
--- a/app/mf/microformats.go
+++ b/app/mf/microformats.go
@@ -18,7 +18,7 @@ type IndiewebAuthor struct {
 	Picture string `json:"picture"`
 }
 
-func (ia IndiewebAuthor) Anonymize() {
+func (ia *IndiewebAuthor) Anonymize() {
 	ia.Picture = fmt.Sprintf("/pictures/%s", Anonymous)
 }
 
diff --git a/app/webmention/handler_test.go b/app/webmention/handler_test.go
new file mode 100644
index 0000000..350e8a2
--- /dev/null
+++ b/app/webmention/handler_test.go
@@ -0,0 +1,64 @@
+package webmention
+
+import (
+	"brainbaking.com/go-jamming/common"
+	"brainbaking.com/go-jamming/db"
+	"github.com/stretchr/testify/assert"
+	"io/ioutil"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"sync"
+	"testing"
+)
+
+func postWm(source string, target string) url.Values {
+	values := url.Values{}
+	values.Set("source", source)
+	values.Set("target", target)
+	return values
+}
+
+var (
+	cnf  = common.Configure()
+	repo db.MentionRepo
+)
+
+func init() {
+	cnf.ConString = ":memory:"
+	repo = db.NewMentionRepo(cnf)
+}
+
+func TestHandlePostWithInvalidUrlsShouldReturnBadRequest(t *testing.T) {
+	ts := httptest.NewServer(HandlePost(cnf, repo))
+	defer ts.Close()
+	res, err := http.PostForm(ts.URL, postWm("https://haha.be/woof/said/the/dog.txt", "https://pussies.nl/mycatjustthrewup/gottacleanup.html"))
+	assert.NoError(t, err)
+
+	content, err := ioutil.ReadAll(res.Body)
+	defer res.Body.Close()
+	assert.NoError(t, err)
+	assert.Contains(t, string(content), "Bad Request")
+}
+
+// Explicitly tests using actual live data, so this could fail if URLs are unreachable.
+func TestHandlePostWithTestServer_Parallel(t *testing.T) {
+	ts := httptest.NewServer(HandlePost(cnf, repo))
+	defer ts.Close()
+	var wg sync.WaitGroup
+
+	for i := 0; i < 5; i++ {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			res, err := http.PostForm(ts.URL, postWm("https://jefklakscodex.com/articles/retrospectives/raven-shield-17-years-later/", "https://brainbaking.com/post/2020/10/building-a-core2duo-winxp-retro-pc/"))
+			assert.NoError(t, err)
+
+			content, err := ioutil.ReadAll(res.Body)
+			defer res.Body.Close()
+			assert.NoError(t, err)
+			assert.Contains(t, string(content), "Thanks, bro. Will process this soon, pinky swear")
+		}()
+	}
+	wg.Wait()
+}
diff --git a/app/webmention/recv/receive_test.go b/app/webmention/recv/receive_test.go
index e4aa070..42f0d05 100644
--- a/app/webmention/recv/receive_test.go
+++ b/app/webmention/recv/receive_test.go
@@ -76,7 +76,7 @@ func TestSaveAuthorPictureLocally(t *testing.T) {
 	}
 }
 
-func BenchmarkReceive(b *testing.B) {
+func BenchmarkReceiveWithoutRestCalls(b *testing.B) {
 	origLog := zerolog.GlobalLevel()
 	zerolog.SetGlobalLevel(zerolog.Disabled)
 	defer zerolog.SetGlobalLevel(origLog)