diff --git a/promql/engine.go b/promql/engine.go
index 72f019e00b..1cdac0828e 100644
--- a/promql/engine.go
+++ b/promql/engine.go
@@ -59,7 +59,7 @@ var (
 			Namespace:   namespace,
 			Subsystem:   subsystem,
 			Name:        "query_duration_seconds",
-			Help:        "Query timmings",
+			Help:        "Query timings",
 			ConstLabels: prometheus.Labels{"slice": "prepare_time"},
 		},
 	)
@@ -68,7 +68,7 @@ var (
 			Namespace:   namespace,
 			Subsystem:   subsystem,
 			Name:        "query_duration_seconds",
-			Help:        "Query timmings",
+			Help:        "Query timings",
 			ConstLabels: prometheus.Labels{"slice": "inner_eval"},
 		},
 	)
@@ -77,7 +77,7 @@ var (
 			Namespace:   namespace,
 			Subsystem:   subsystem,
 			Name:        "query_duration_seconds",
-			Help:        "Query timmings",
+			Help:        "Query timings",
 			ConstLabels: prometheus.Labels{"slice": "result_append"},
 		},
 	)
@@ -86,7 +86,7 @@ var (
 			Namespace:   namespace,
 			Subsystem:   subsystem,
 			Name:        "query_duration_seconds",
-			Help:        "Query timmings",
+			Help:        "Query timings",
 			ConstLabels: prometheus.Labels{"slice": "result_sort"},
 		},
 	)
diff --git a/web/api/v1/api.go b/web/api/v1/api.go
index 9a2e2361be..b7e9512f8b 100644
--- a/web/api/v1/api.go
+++ b/web/api/v1/api.go
@@ -169,12 +169,24 @@ func (api *API) query(r *http.Request) (interface{}, *apiError) {
 		ts = api.now()
 	}
 
+	ctx := api.context(r)
+	if to := r.FormValue("timeout"); to != "" {
+		var cancel context.CancelFunc
+		timeout, err := parseDuration(to)
+		if err != nil {
+			return nil, &apiError{errorBadData, err}
+		}
+
+		ctx, cancel = context.WithTimeout(ctx, timeout)
+		defer cancel()
+	}
+
 	qry, err := api.QueryEngine.NewInstantQuery(r.FormValue("query"), ts)
 	if err != nil {
 		return nil, &apiError{errorBadData, err}
 	}
 
-	res := qry.Exec(api.context(r))
+	res := qry.Exec(ctx)
 	if res.Err != nil {
 		switch res.Err.(type) {
 		case promql.ErrQueryCanceled:
@@ -221,12 +233,24 @@ func (api *API) queryRange(r *http.Request) (interface{}, *apiError) {
 		return nil, &apiError{errorBadData, err}
 	}
 
+	ctx := api.context(r)
+	if to := r.FormValue("timeout"); to != "" {
+		var cancel context.CancelFunc
+		timeout, err := parseDuration(to)
+		if err != nil {
+			return nil, &apiError{errorBadData, err}
+		}
+
+		ctx, cancel = context.WithTimeout(ctx, timeout)
+		defer cancel()
+	}
+
 	qry, err := api.QueryEngine.NewRangeQuery(r.FormValue("query"), start, end, step)
 	if err != nil {
 		return nil, &apiError{errorBadData, err}
 	}
 
-	res := qry.Exec(api.context(r))
+	res := qry.Exec(ctx)
 	if res.Err != nil {
 		switch res.Err.(type) {
 		case promql.ErrQueryCanceled:
@@ -345,6 +369,7 @@ func (api *API) dropSeries(r *http.Request) (interface{}, *apiError) {
 	return res, nil
 }
 
+// Target has the information for one target.
 type Target struct {
 	// Labels before any processing.
 	DiscoveredLabels model.LabelSet `json:"discoveredLabels"`
@@ -358,6 +383,7 @@ type Target struct {
 	Health     retrieval.TargetHealth `json:"health"`
 }
 
+// TargetDiscovery has all the active targets.
 type TargetDiscovery struct {
 	ActiveTargets []*Target `json:"activeTargets"`
 }
@@ -386,10 +412,12 @@ func (api *API) targets(r *http.Request) (interface{}, *apiError) {
 	return res, nil
 }
 
+// AlertmanagerDiscovery has all the active Alertmanagers.
 type AlertmanagerDiscovery struct {
 	ActiveAlertmanagers []*AlertmanagerTarget `json:"activeAlertmanagers"`
 }
 
+// AlertmanagerTarget has info on one AM.
 type AlertmanagerTarget struct {
 	URL string `json:"url"`
 }