diff --git a/endpoints/openrtb2/amp_auction.go b/endpoints/openrtb2/amp_auction.go
index bfd8fb3fe60..ebcb5e577b2 100644
--- a/endpoints/openrtb2/amp_auction.go
+++ b/endpoints/openrtb2/amp_auction.go
@@ -226,7 +226,7 @@ func enforceAMPCache(req *openrtb.BidRequest) (errs []error) {
 
 	// Ensure Targeting and caching is on
 	if extRequest.Prebid.Targeting == nil || extRequest.Prebid.Cache == nil || extRequest.Prebid.Cache.Bids == nil {
-		errs = []error{fmt.Errorf("AMP requests require Trageting and Caching to be set")}
+		errs = []error{fmt.Errorf("AMP requests require Targeting and Caching to be set")}
 	}
 
 	return
diff --git a/pbs_light.go b/pbs_light.go
index 148f7caa746..38a7a3b94bd 100644
--- a/pbs_light.go
+++ b/pbs_light.go
@@ -211,7 +211,8 @@ func (deps *cookieSyncDeps) CookieSync(w http.ResponseWriter, r *http.Request, _
 	defer r.Body.Close()
 
 	csReq := &cookieSyncRequest{}
-	err := json.NewDecoder(r.Body).Decode(&csReq)
+	csReqRaw := map[string]json.RawMessage{}
+	err := json.NewDecoder(r.Body).Decode(&csReqRaw)
 	if err != nil {
 		if glog.V(2) {
 			glog.Infof("Failed to parse /cookie_sync request body: %v", err)
@@ -219,6 +220,28 @@ func (deps *cookieSyncDeps) CookieSync(w http.ResponseWriter, r *http.Request, _
 		http.Error(w, "JSON parse failed", http.StatusBadRequest)
 		return
 	}
+	if UUID, ok := csReqRaw["uuid"]; ok {
+		err := json.Unmarshal(UUID, &csReq.UUID)
+		if err != nil {
+			if glog.V(2) {
+				glog.Infof("Failed to parse /cookie_sync request body (UUID): %v", err)
+			}
+			http.Error(w, "JSON parse failed (uuid)", http.StatusBadRequest)
+			return
+		}
+	}
+	biddersOmitted := true
+	if biddersRaw, ok := csReqRaw["bidders"]; ok {
+		biddersOmitted = false
+		err := json.Unmarshal(biddersRaw, &csReq.Bidders)
+		if err != nil {
+			if glog.V(2) {
+				glog.Infof("Failed to parse /cookie_sync request body (bidders list): %v", err)
+			}
+			http.Error(w, "JSON parse failed (bidders)", http.StatusBadRequest)
+			return
+		}
+	}
 
 	csResp := cookieSyncResponse{
 		UUID:         csReq.UUID,
@@ -231,6 +254,14 @@ func (deps *cookieSyncDeps) CookieSync(w http.ResponseWriter, r *http.Request, _
 		csResp.Status = "ok"
 	}
 
+	// If at the end (After possibly reading stored bidder lists) there still are no bidders,
+	// and "bidders" is not found in the JSON, sync all bidders
+	if len(csReq.Bidders) == 0 && biddersOmitted {
+		for bidder, _ := range deps.syncers {
+			csReq.Bidders = append(csReq.Bidders, string(bidder))
+		}
+	}
+
 	for _, bidder := range csReq.Bidders {
 		if syncer, ok := deps.syncers[openrtb_ext.BidderName(bidder)]; ok {
 			if !userSyncCookie.HasLiveSync(syncer.FamilyName()) {
diff --git a/pbs_light_test.go b/pbs_light_test.go
index 915e00cab70..70795292406 100644
--- a/pbs_light_test.go
+++ b/pbs_light_test.go
@@ -43,7 +43,7 @@ func TestCookieSyncNoCookies(t *testing.T) {
 	rr := httptest.NewRecorder()
 	router.ServeHTTP(rr, req)
 	if rr.Code != http.StatusOK {
-		t.Fatalf("Wrong status: %d", rr.Code)
+		t.Fatalf("Wrong status: %d (%s)", rr.Code, rr.Body)
 	}
 
 	csresp := cookieSyncResponse{}
@@ -53,7 +53,7 @@ func TestCookieSyncNoCookies(t *testing.T) {
 	}
 
 	if csresp.UUID != csreq.UUID {
-		t.Error("UUIDs didn't match")
+		t.Errorf("UUIDs didn't match (expected: %s   found: %s)", csreq.UUID, csresp.UUID)
 	}
 
 	if csresp.Status != "no_cookie" {
@@ -113,10 +113,78 @@ func TestCookieSyncHasCookies(t *testing.T) {
 	}
 }
 
+func TestCookieSyncNoBidders(t *testing.T) {
+	endpoint := testableEndpoint()
+
+	router := httprouter.New()
+	router.POST("/cookie_sync", endpoint)
+
+	// First test a declared empty bidders returns no syncs
+	csreq := []byte("{\"uuid\": \"abcdefg\", \"bidders\": []}")
+	csbuf := bytes.NewBuffer(csreq)
+
+	req, _ := http.NewRequest("POST", "/cookie_sync", csbuf)
+	rr := httptest.NewRecorder()
+	router.ServeHTTP(rr, req)
+	if rr.Code != http.StatusOK {
+		t.Fatalf("Wrong status: %d (%s)", rr.Code, rr.Body)
+	}
+
+	csresp := cookieSyncResponse{}
+	err := json.Unmarshal(rr.Body.Bytes(), &csresp)
+	if err != nil {
+		t.Fatalf("Unmarshal response failed: %v", err)
+	}
+
+	if csresp.UUID != "abcdefg" {
+		t.Errorf("UUIDs didn't match (expected: abcdefg   found: %s)", csresp.UUID)
+	}
+
+	if csresp.Status != "no_cookie" {
+		t.Errorf("Expected status = no_cookie; got %s", csresp.Status)
+	}
+
+	if len(csresp.BidderStatus) != 0 {
+		t.Errorf("Expected 0 bidder status rows; got %d", len(csresp.BidderStatus))
+	}
+
+	// Now test a missing bidders returns all syncs
+	csreq = []byte("{\"uuid\": \"abcdefg\"}")
+	csbuf = bytes.NewBuffer(csreq)
+
+	req, _ = http.NewRequest("POST", "/cookie_sync", csbuf)
+	rr = httptest.NewRecorder()
+	router.ServeHTTP(rr, req)
+	if rr.Code != http.StatusOK {
+		t.Fatalf("Wrong status: %d (%s)", rr.Code, rr.Body)
+	}
+
+	csresp = cookieSyncResponse{}
+	err = json.Unmarshal(rr.Body.Bytes(), &csresp)
+	if err != nil {
+		t.Fatalf("Unmarshal response failed: %v", err)
+	}
+
+	if csresp.UUID != "abcdefg" {
+		t.Errorf("UUIDs didn't match (expected: abcdefg   found: %s)", csresp.UUID)
+	}
+
+	if csresp.Status != "no_cookie" {
+		t.Errorf("Expected status = no_cookie; got %s", csresp.Status)
+	}
+
+	if len(csresp.BidderStatus) != 4 {
+		t.Errorf("Expected %d bidder status rows; got %d", 4, len(csresp.BidderStatus))
+	}
+
+}
+
 func testableEndpoint() httprouter.Handle {
 	knownSyncers := map[openrtb_ext.BidderName]usersyncers.Usersyncer{
-		openrtb_ext.BidderAppnexus: usersyncers.NewAppnexusSyncer("someurl.com"),
-		openrtb_ext.BidderFacebook: usersyncers.NewFacebookSyncer("facebookurl.com"),
+		openrtb_ext.BidderAppnexus:   usersyncers.NewAppnexusSyncer("someurl.com"),
+		openrtb_ext.BidderFacebook:   usersyncers.NewFacebookSyncer("facebookurl.com"),
+		openrtb_ext.BidderLifestreet: usersyncers.NewLifestreetSyncer("anotherurl.com"),
+		openrtb_ext.BidderPubmatic:   usersyncers.NewPubmaticSyncer("thaturl.com"),
 	}
 	return (&cookieSyncDeps{knownSyncers, &config.Cookie{}, metrics.NewMeter()}).CookieSync
 }