diff --git a/cmd/proxy/actions/app.go b/cmd/proxy/actions/app.go
index 74df44abf..acc686710 100644
--- a/cmd/proxy/actions/app.go
+++ b/cmd/proxy/actions/app.go
@@ -52,7 +52,6 @@ func App(logger *log.Logger, conf *config.Config) (http.Handler, error) {
 			SSLRedirect:     conf.ForceSSL,
 			SSLProxyHeaders: map[string]string{"X-Forwarded-Proto": "https"},
 		}).Handler,
-		mw.ContentType,
 	)
 
 	var subRouter *mux.Router
diff --git a/cmd/proxy/actions/catalog.go b/cmd/proxy/actions/catalog.go
index 769208f1e..96847b7c6 100644
--- a/cmd/proxy/actions/catalog.go
+++ b/cmd/proxy/actions/catalog.go
@@ -23,6 +23,7 @@ func catalogHandler(s storage.Backend) http.HandlerFunc {
 	const op errors.Op = "actions.CatalogHandler"
 	cs, isCataloger := s.(storage.Cataloger)
 	f := func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json; charset=utf-8")
 		if !isCataloger {
 			w.WriteHeader(errors.KindNotImplemented)
 			return
diff --git a/cmd/proxy/actions/health.go b/cmd/proxy/actions/health.go
index 8c34b33ca..53fc5f25e 100644
--- a/cmd/proxy/actions/health.go
+++ b/cmd/proxy/actions/health.go
@@ -5,5 +5,6 @@ import (
 )
 
 func healthHandler(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Type", "application/json")
 	w.WriteHeader(http.StatusOK)
 }
diff --git a/cmd/proxy/actions/home.go b/cmd/proxy/actions/home.go
index 8f41b979e..f73815444 100644
--- a/cmd/proxy/actions/home.go
+++ b/cmd/proxy/actions/home.go
@@ -125,7 +125,7 @@ func proxyHomeHandler(c *config.Config) http.HandlerFunc {
 			w.WriteHeader(http.StatusInternalServerError)
 		}
 
-		w.Header().Add("Content-Type", "text/html")
+		w.Header().Set("Content-Type", "text/html")
 		w.WriteHeader(http.StatusOK)
 
 		err = tmp.ExecuteTemplate(w, "home", templateData)
diff --git a/cmd/proxy/actions/index.go b/cmd/proxy/actions/index.go
index e747a7abb..1e4744e8d 100644
--- a/cmd/proxy/actions/index.go
+++ b/cmd/proxy/actions/index.go
@@ -23,6 +23,8 @@ func indexHandler(index index.Indexer) http.HandlerFunc {
 			http.Error(w, err.Error(), errors.Kind(err))
 			return
 		}
+
+		w.Header().Set("Content-Type", "application/json; charset=utf-8")
 		enc := json.NewEncoder(w)
 		for _, meta := range list {
 			if err = enc.Encode(meta); err != nil {
diff --git a/cmd/proxy/actions/readiness.go b/cmd/proxy/actions/readiness.go
index 48a900d53..515a603bf 100644
--- a/cmd/proxy/actions/readiness.go
+++ b/cmd/proxy/actions/readiness.go
@@ -9,6 +9,7 @@ import (
 func getReadinessHandler(s storage.Backend) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		if _, err := s.List(r.Context(), "github.com/gomods/athens"); err != nil {
+			w.Header().Set("Content-Type", "application/json; charset=utf-8")
 			w.WriteHeader(http.StatusInternalServerError)
 		}
 	}
diff --git a/cmd/proxy/actions/robots.go b/cmd/proxy/actions/robots.go
index b7edb1358..67ad8e3cf 100644
--- a/cmd/proxy/actions/robots.go
+++ b/cmd/proxy/actions/robots.go
@@ -9,6 +9,7 @@ import (
 // robotsHandler implements GET baseURL/robots.txt.
 func robotsHandler(c *config.Config) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "text/plain; charset=utf-8")
 		http.ServeFile(w, r, c.RobotsFile)
 	}
 }
diff --git a/cmd/proxy/actions/version.go b/cmd/proxy/actions/version.go
index a0cba0120..7ca732203 100644
--- a/cmd/proxy/actions/version.go
+++ b/cmd/proxy/actions/version.go
@@ -9,4 +9,6 @@ import (
 
 func versionHandler(w http.ResponseWriter, r *http.Request) {
 	_ = json.NewEncoder(w).Encode(build.Data())
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	w.WriteHeader(http.StatusOK)
 }
diff --git a/pkg/download/latest.go b/pkg/download/latest.go
index 6e5aad194..357f00054 100644
--- a/pkg/download/latest.go
+++ b/pkg/download/latest.go
@@ -17,6 +17,7 @@ const PathLatest = "/{module:.+}/@latest"
 func LatestHandler(dp Protocol, lggr log.Entry, df *mode.DownloadFile) http.Handler {
 	const op errors.Op = "download.LatestHandler"
 	f := func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "text/plain; charset=utf-8")
 		mod, err := paths.GetModule(r)
 		if err != nil {
 			lggr.SystemErr(errors.E(op, err))
diff --git a/pkg/download/list.go b/pkg/download/list.go
index 405fbca47..dd94e8c92 100644
--- a/pkg/download/list.go
+++ b/pkg/download/list.go
@@ -18,6 +18,7 @@ const PathList = "/{module:.+}/@v/list"
 func ListHandler(dp Protocol, lggr log.Entry, df *mode.DownloadFile) http.Handler {
 	const op errors.Op = "download.ListHandler"
 	f := func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json; charset=utf-8")
 		mod, err := paths.GetModule(r)
 		if err != nil {
 			lggr.SystemErr(errors.E(op, err))
diff --git a/pkg/download/version_info.go b/pkg/download/version_info.go
index 3a6c96035..d68adb523 100644
--- a/pkg/download/version_info.go
+++ b/pkg/download/version_info.go
@@ -15,6 +15,7 @@ const PathVersionInfo = "/{module:.+}/@v/{version}.info"
 func InfoHandler(dp Protocol, lggr log.Entry, df *mode.DownloadFile) http.Handler {
 	const op errors.Op = "download.InfoHandler"
 	f := func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json; charset=utf-8")
 		mod, ver, err := getModuleParams(r, op)
 		if err != nil {
 			lggr.SystemErr(err)
diff --git a/pkg/download/version_module.go b/pkg/download/version_module.go
index 1a1002308..08b423da7 100644
--- a/pkg/download/version_module.go
+++ b/pkg/download/version_module.go
@@ -15,6 +15,7 @@ const PathVersionModule = "/{module:.+}/@v/{version}.mod"
 func ModuleHandler(dp Protocol, lggr log.Entry, df *mode.DownloadFile) http.Handler {
 	const op errors.Op = "download.VersionModuleHandler"
 	f := func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "text/plain; charset=utf-8")
 		mod, ver, err := getModuleParams(r, op)
 		if err != nil {
 			err = errors.E(op, errors.M(mod), errors.V(ver), err)