diff --git a/http/handler.go b/http/handler.go
index 58fdcb8b6..a079ae479 100644
--- a/http/handler.go
+++ b/http/handler.go
@@ -283,24 +283,24 @@ func (h *Handler) handleHome(w http.ResponseWriter, r *http.Request) {
 	http.Error(w, "Welcome. Pilosa is running. Visit https://www.pilosa.com/docs/ for more information.", http.StatusNotFound)
 }
 
-func checkHeaderAcceptJSON(header http.Header) bool {
-	v, found := header["Accept"]
-	sendError := false
-	if found {
-		sendError = true
+// validHeaderAcceptJSON returns false if one or more Accept
+// headers are present, but none of them are "application/json"
+// (or any matching wildcard). Otherwise returns true.
+func validHeaderAcceptJSON(header http.Header) bool {
+	if v, found := header["Accept"]; found {
 		for _, v := range v {
-			if v == "application/json" {
-				sendError = false
-
+			if v == "application/json" || v == "*/*" || v == "*/json" || v == "application/*" {
+				return true
 			}
 		}
+		return false
 	}
-	return sendError
+	return true
 }
 
 // handleGetSchema handles GET /schema requests.
 func (h *Handler) handleGetSchema(w http.ResponseWriter, r *http.Request) {
-	if checkHeaderAcceptJSON(r.Header) {
+	if !validHeaderAcceptJSON(r.Header) {
 		http.Error(w, "JSON only acceptable response", http.StatusNotAcceptable)
 		return
 	}
@@ -315,7 +315,7 @@ func (h *Handler) handleGetSchema(w http.ResponseWriter, r *http.Request) {
 
 // handleGetStatus handles GET /status requests.
 func (h *Handler) handleGetStatus(w http.ResponseWriter, r *http.Request) {
-	if checkHeaderAcceptJSON(r.Header) {
+	if !validHeaderAcceptJSON(r.Header) {
 		http.Error(w, "JSON only acceptable response", http.StatusNotAcceptable)
 		return
 	}
@@ -330,7 +330,7 @@ func (h *Handler) handleGetStatus(w http.ResponseWriter, r *http.Request) {
 }
 
 func (h *Handler) handleGetInfo(w http.ResponseWriter, r *http.Request) {
-	if checkHeaderAcceptJSON(r.Header) {
+	if !validHeaderAcceptJSON(r.Header) {
 		http.Error(w, "JSON only acceptable response", http.StatusNotAcceptable)
 		return
 	}
@@ -387,7 +387,7 @@ func (h *Handler) handlePostQuery(w http.ResponseWriter, r *http.Request) {
 
 // handleGetSlicesMax handles GET /schema requests.
 func (h *Handler) handleGetSlicesMax(w http.ResponseWriter, r *http.Request) {
-	if checkHeaderAcceptJSON(r.Header) {
+	if !validHeaderAcceptJSON(r.Header) {
 		http.Error(w, "JSON only acceptable response", http.StatusNotAcceptable)
 		return
 	}
@@ -409,7 +409,7 @@ func (h *Handler) handleGetIndexes(w http.ResponseWriter, r *http.Request) {
 
 // handleGetIndex handles GET /index/<indexname> requests.
 func (h *Handler) handleGetIndex(w http.ResponseWriter, r *http.Request) {
-	if checkHeaderAcceptJSON(r.Header) {
+	if !validHeaderAcceptJSON(r.Header) {
 		http.Error(w, "JSON only acceptable response", http.StatusNotAcceptable)
 		return
 	}
@@ -491,7 +491,7 @@ type postIndexResponse struct{}
 
 // handleDeleteIndex handles DELETE /index request.
 func (h *Handler) handleDeleteIndex(w http.ResponseWriter, r *http.Request) {
-	if checkHeaderAcceptJSON(r.Header) {
+	if !validHeaderAcceptJSON(r.Header) {
 		http.Error(w, "JSON only acceptable response", http.StatusNotAcceptable)
 		return
 	}
@@ -513,7 +513,7 @@ type deleteIndexResponse struct{}
 
 // handlePostIndex handles POST /index request.
 func (h *Handler) handlePostIndex(w http.ResponseWriter, r *http.Request) {
-	if checkHeaderAcceptJSON(r.Header) {
+	if !validHeaderAcceptJSON(r.Header) {
 		http.Error(w, "JSON only acceptable response", http.StatusNotAcceptable)
 		return
 	}
@@ -547,7 +547,7 @@ func (h *Handler) handlePostIndex(w http.ResponseWriter, r *http.Request) {
 
 // handlePostIndexAttrDiff handles POST /index/attr/diff requests.
 func (h *Handler) handlePostIndexAttrDiff(w http.ResponseWriter, r *http.Request) {
-	if checkHeaderAcceptJSON(r.Header) {
+	if !validHeaderAcceptJSON(r.Header) {
 		http.Error(w, "JSON only acceptable response", http.StatusNotAcceptable)
 		return
 	}
@@ -588,7 +588,7 @@ type postIndexAttrDiffResponse struct {
 
 // handlePostField handles POST /field request.
 func (h *Handler) handlePostField(w http.ResponseWriter, r *http.Request) {
-	if checkHeaderAcceptJSON(r.Header) {
+	if !validHeaderAcceptJSON(r.Header) {
 		http.Error(w, "JSON only acceptable response", http.StatusNotAcceptable)
 		return
 	}
@@ -670,7 +670,7 @@ type postFieldResponse struct{}
 
 // handleDeleteField handles DELETE /field request.
 func (h *Handler) handleDeleteField(w http.ResponseWriter, r *http.Request) {
-	if checkHeaderAcceptJSON(r.Header) {
+	if !validHeaderAcceptJSON(r.Header) {
 		http.Error(w, "JSON only acceptable response", http.StatusNotAcceptable)
 		return
 	}
@@ -700,7 +700,7 @@ type deleteFieldResponse struct{}
 
 // handlePostFieldAttrDiff handles POST /field/attr/diff requests.
 func (h *Handler) handlePostFieldAttrDiff(w http.ResponseWriter, r *http.Request) {
-	if checkHeaderAcceptJSON(r.Header) {
+	if !validHeaderAcceptJSON(r.Header) {
 		http.Error(w, "JSON only acceptable response", http.StatusNotAcceptable)
 		return
 	}
@@ -796,7 +796,7 @@ func (h *Handler) readURLQueryRequest(r *http.Request) (*pilosa.QueryRequest, er
 
 // writeQueryResponse writes the response from the executor to w.
 func (h *Handler) writeQueryResponse(w http.ResponseWriter, r *http.Request, resp *pilosa.QueryResponse) error {
-	if checkHeaderAcceptJSON(r.Header) {
+	if !validHeaderAcceptJSON(r.Header) {
 		return h.writeProtobufQueryResponse(w, resp)
 	}
 	return h.writeJSONQueryResponse(w, resp)
@@ -959,7 +959,7 @@ func (h *Handler) handleGetExportCSV(w http.ResponseWriter, r *http.Request) {
 
 // handleGetFragmentNodes handles /fragment/nodes requests.
 func (h *Handler) handleGetFragmentNodes(w http.ResponseWriter, r *http.Request) {
-	if checkHeaderAcceptJSON(r.Header) {
+	if !validHeaderAcceptJSON(r.Header) {
 		http.Error(w, "JSON only acceptable response", http.StatusNotAcceptable)
 		return
 	}
@@ -1008,7 +1008,7 @@ func (h *Handler) handleGetFragmentBlockData(w http.ResponseWriter, r *http.Requ
 
 // handleGetFragmentBlocks handles GET /fragment/blocks requests.
 func (h *Handler) handleGetFragmentBlocks(w http.ResponseWriter, r *http.Request) {
-	if checkHeaderAcceptJSON(r.Header) {
+	if !validHeaderAcceptJSON(r.Header) {
 		http.Error(w, "JSON only acceptable response", http.StatusNotAcceptable)
 		return
 	}
@@ -1044,7 +1044,7 @@ type getFragmentBlocksResponse struct {
 
 // handleGetVersion handles /version requests.
 func (h *Handler) handleGetVersion(w http.ResponseWriter, r *http.Request) {
-	if checkHeaderAcceptJSON(r.Header) {
+	if !validHeaderAcceptJSON(r.Header) {
 		http.Error(w, "JSON only acceptable response", http.StatusNotAcceptable)
 		return
 	}
@@ -1146,7 +1146,7 @@ func errorString(err error) string {
 }
 
 func (h *Handler) handlePostClusterResizeSetCoordinator(w http.ResponseWriter, r *http.Request) {
-	if checkHeaderAcceptJSON(r.Header) {
+	if !validHeaderAcceptJSON(r.Header) {
 		http.Error(w, "JSON only acceptable response", http.StatusNotAcceptable)
 		return
 	}
@@ -1187,7 +1187,7 @@ type setCoordinatorResponse struct {
 
 // handlePostClusterResizeRemoveNode handles POST /cluster/resize/remove-node request.
 func (h *Handler) handlePostClusterResizeRemoveNode(w http.ResponseWriter, r *http.Request) {
-	if checkHeaderAcceptJSON(r.Header) {
+	if !validHeaderAcceptJSON(r.Header) {
 		http.Error(w, "JSON only acceptable response", http.StatusNotAcceptable)
 		return
 	}
@@ -1227,7 +1227,7 @@ type removeNodeResponse struct {
 
 // handlePostClusterResizeAbort handles POST /cluster/resize/abort request.
 func (h *Handler) handlePostClusterResizeAbort(w http.ResponseWriter, r *http.Request) {
-	if checkHeaderAcceptJSON(r.Header) {
+	if !validHeaderAcceptJSON(r.Header) {
 		http.Error(w, "JSON only acceptable response", http.StatusNotAcceptable)
 		return
 	}
@@ -1268,7 +1268,7 @@ func (h *Handler) handleRecalculateCaches(w http.ResponseWriter, r *http.Request
 }
 
 func (h *Handler) handlePostClusterMessage(w http.ResponseWriter, r *http.Request) {
-	if checkHeaderAcceptJSON(r.Header) {
+	if !validHeaderAcceptJSON(r.Header) {
 		http.Error(w, "JSON only acceptable response", http.StatusNotAcceptable)
 		return
 	}