diff --git a/common/httpapi.go b/common/httpapi.go
index 843336f5b..e5324bd17 100644
--- a/common/httpapi.go
+++ b/common/httpapi.go
@@ -1,7 +1,12 @@
 package common
 
 import (
+	"io"
 	"net/http"
+	"net/http/httptest"
+	"net/http/httputil"
+	"os"
+	"strings"
 	"time"
 
 	"github.com/matrix-org/dendrite/clientapi/auth"
@@ -46,12 +51,60 @@ func MakeAuthAPI(
 // MakeExternalAPI turns a util.JSONRequestHandler function into an http.Handler.
 // This is used for APIs that are called from the internet.
 func MakeExternalAPI(metricsName string, f func(*http.Request) util.JSONResponse) http.Handler {
+	// TODO: We shouldn't be directly reading env vars here, inject it in instead.
+	// Refactor this when we split out config structs.
+	verbose := false
+	if os.Getenv("DENDRITE_TRACE_HTTP") == "1" {
+		verbose = true
+	}
 	h := util.MakeJSONAPI(util.NewJSONRequestHandler(f))
 	withSpan := func(w http.ResponseWriter, req *http.Request) {
+		nextWriter := w
+		if verbose {
+			logger := logrus.NewEntry(logrus.StandardLogger())
+			// Log outgoing response
+			rec := httptest.NewRecorder()
+			nextWriter = rec
+			defer func() {
+				resp := rec.Result()
+				dump, err := httputil.DumpResponse(resp, true)
+				if err != nil {
+					logger.Debugf("Failed to dump outgoing response: %s", err)
+				} else {
+					strSlice := strings.Split(string(dump), "\n")
+					for _, s := range strSlice {
+						logger.Debug(s)
+					}
+				}
+				// copy the response to the client
+				for hdr, vals := range resp.Header {
+					for _, val := range vals {
+						w.Header().Add(hdr, val)
+					}
+				}
+				w.WriteHeader(resp.StatusCode)
+				// discard errors as this is for debugging
+				_, _ = io.Copy(w, resp.Body)
+				_ = resp.Body.Close()
+			}()
+
+			// Log incoming request
+			dump, err := httputil.DumpRequest(req, true)
+			if err != nil {
+				logger.Debugf("Failed to dump incoming request: %s", err)
+			} else {
+				strSlice := strings.Split(string(dump), "\n")
+				for _, s := range strSlice {
+					logger.Debug(s)
+				}
+			}
+		}
+
 		span := opentracing.StartSpan(metricsName)
 		defer span.Finish()
 		req = req.WithContext(opentracing.ContextWithSpan(req.Context(), span))
-		h.ServeHTTP(w, req)
+		h.ServeHTTP(nextWriter, req)
+
 	}
 
 	return http.HandlerFunc(withSpan)
diff --git a/go.mod b/go.mod
index 3d72aa86b..953b49d32 100644
--- a/go.mod
+++ b/go.mod
@@ -17,7 +17,7 @@ require (
 	github.com/matrix-org/go-http-js-libp2p v0.0.0-20200318135427-31631a9ef51f
 	github.com/matrix-org/go-sqlite3-js v0.0.0-20200325174927-327088cdef10
 	github.com/matrix-org/gomatrix v0.0.0-20190528120928-7df988a63f26
-	github.com/matrix-org/gomatrixserverlib v0.0.0-20200409140603-8b9a51fe9b89
+	github.com/matrix-org/gomatrixserverlib v0.0.0-20200415145257-d492cd4be836
 	github.com/matrix-org/naffka v0.0.0-20200127221512-0716baaabaf1
 	github.com/matrix-org/util v0.0.0-20190711121626-527ce5ddefc7
 	github.com/mattn/go-sqlite3 v2.0.3+incompatible
diff --git a/go.sum b/go.sum
index 70faff757..f7295c38b 100644
--- a/go.sum
+++ b/go.sum
@@ -364,8 +364,8 @@ github.com/matrix-org/gomatrix v0.0.0-20190528120928-7df988a63f26 h1:Hr3zjRsq2bh
 github.com/matrix-org/gomatrix v0.0.0-20190528120928-7df988a63f26/go.mod h1:3fxX6gUjWyI/2Bt7J1OLhpCzOfO/bB3AiX0cJtEKud0=
 github.com/matrix-org/gomatrixserverlib v0.0.0-20200124100636-0c2ec91d1df5 h1:kmRjpmFOenVpOaV/DRlo9p6z/IbOKlUC+hhKsAAh8Qg=
 github.com/matrix-org/gomatrixserverlib v0.0.0-20200124100636-0c2ec91d1df5/go.mod h1:FsKa2pWE/bpQql9H7U4boOPXFoJX/QcqaZZ6ijLkaZI=
-github.com/matrix-org/gomatrixserverlib v0.0.0-20200409140603-8b9a51fe9b89 h1:YAlUJK/Ty2ZrP/DL41CiR0Cp3pteshnyIS420KVs220=
-github.com/matrix-org/gomatrixserverlib v0.0.0-20200409140603-8b9a51fe9b89/go.mod h1:FsKa2pWE/bpQql9H7U4boOPXFoJX/QcqaZZ6ijLkaZI=
+github.com/matrix-org/gomatrixserverlib v0.0.0-20200415145257-d492cd4be836 h1:YiXBJ/0ZeBzuh9Ym0iYaJgDBlFdz7nIVKArqkkEgPzM=
+github.com/matrix-org/gomatrixserverlib v0.0.0-20200415145257-d492cd4be836/go.mod h1:FsKa2pWE/bpQql9H7U4boOPXFoJX/QcqaZZ6ijLkaZI=
 github.com/matrix-org/naffka v0.0.0-20200127221512-0716baaabaf1 h1:osLoFdOy+ChQqVUn2PeTDETFftVkl4w9t/OW18g3lnk=
 github.com/matrix-org/naffka v0.0.0-20200127221512-0716baaabaf1/go.mod h1:cXoYQIENbdWIQHt1SyCo6Bl3C3raHwJ0wgVrXHSqf+A=
 github.com/matrix-org/util v0.0.0-20171127121716-2e2df66af2f5 h1:W7l5CP4V7wPyPb4tYE11dbmeAOwtFQBTW0rf4OonOS8=
diff --git a/syncapi/routing/messages.go b/syncapi/routing/messages.go
index c9d62477d..873ee9366 100644
--- a/syncapi/routing/messages.go
+++ b/syncapi/routing/messages.go
@@ -209,18 +209,12 @@ func (r *messagesReq) retrieveEvents() (
 		return []gomatrixserverlib.ClientEvent{}, r.from, r.to, nil
 	}
 
-	// Sort the events to ensure we send them in the right order. We currently
-	// do that based on the event's timestamp.
+	// Sort the events to ensure we send them in the right order.
+	events = gomatrixserverlib.HeaderedReverseTopologicalOrdering(events)
 	if r.backwardOrdering {
-		sort.SliceStable(events, func(i int, j int) bool {
-			// Backward ordering is antichronological (latest event to oldest
-			// one).
-			return sortEvents(&(events[j]), &(events[i]))
-		})
-	} else {
-		sort.SliceStable(events, func(i int, j int) bool {
-			// Forward ordering is chronological (oldest event to latest one).
-			return sortEvents(&(events[i]), &(events[j]))
+		// This reverses the array from old->new to new->old
+		sort.SliceStable(events, func(i, j int) bool {
+			return true
 		})
 	}
 
@@ -493,12 +487,3 @@ func setToDefault(
 
 	return
 }
-
-// sortEvents is a function to give to sort.SliceStable, and compares the
-// timestamp of two Matrix events.
-// Returns true if the first event happened before the second one, false
-// otherwise.
-func sortEvents(e1 *gomatrixserverlib.HeaderedEvent, e2 *gomatrixserverlib.HeaderedEvent) bool {
-	t := e1.OriginServerTS().Time()
-	return e2.OriginServerTS().Time().After(t)
-}