diff --git a/succbone/succd/http.go b/succbone/succd/http.go
index fd39c87..d32d274 100644
--- a/succbone/succd/http.go
+++ b/succbone/succd/http.go
@@ -50,6 +50,90 @@ func formatMbar(v float32) template.HTML {
 	return template.HTML(res)
 }
 
+// apiData is the data model served to the user via HTTP/WebSockets
+type apiData struct {
+	// Safety interlocks.
+	Safety struct {
+		// Failsafe mode enabled - pirani gauge seems disconnected.
+		Failsafe bool
+		// HighPressure interlock enabled - pressure too high to run diffusion
+		// pump.
+		HighPressure bool
+	}
+	// Pirani gauge data.
+	Pirani struct {
+		// Volts read from the gauge (0-10).
+		Volts string
+		// Mbar read from the gauge, formatted as HTML.
+		Mbar template.HTML
+		// MbarFloat read from the gauge.
+		MbarFloat float32
+	}
+	// Pump state.
+	Pumps struct {
+		// RPOn means the roughing pump is turned on.
+		RPOn bool
+		// DPOn means the diffusion pump is turned on.
+		DPOn bool
+	}
+	// Pressure feedback into evacuation board.
+	Feedback struct {
+		// RoughReached is true when the system has reached a rough vacuum
+		// stage.
+		RoughReached bool
+		// HighReached is true when the system has reached a high vacuum stage.
+		HighReached bool
+	}
+	// System junk.
+	System struct {
+		// Load of the system.
+		Load string
+		// Hostname of the system.
+		Hostname string
+	}
+}
+
+// apiData returns the user data model for the current state of the system. If
+// skipSystem is set, the System subset is ignored (saves system load, and is
+// not being served via websockets).
+func (d *daemon) apiData(skipSystem bool) *apiData {
+	volts, mbar := d.pirani()
+	rp := d.rpGet()
+	dp := d.dpGet()
+	rough, high := d.vacuumStatusGet()
+	safety := d.safetyStatusGet()
+
+	var hostname, load string
+	var err error
+
+	if !skipSystem {
+		hostname, err = os.Hostname()
+		if err != nil {
+			hostname = "unknown"
+		}
+		loadB, err := os.ReadFile("/proc/loadavg")
+		load = "unknown"
+		if err == nil {
+			parts := strings.Fields(string(loadB))
+			load = strings.Join(parts[:3], " ")
+		}
+	}
+
+	ad := apiData{}
+	ad.Safety.Failsafe = safety.failsafe
+	ad.Safety.HighPressure = safety.highPressure
+	ad.Pirani.Volts = formatVolts(volts)
+	ad.Pirani.Mbar = formatMbar(mbar)
+	ad.Pirani.MbarFloat = mbar
+	ad.Pumps.RPOn = rp
+	ad.Pumps.DPOn = dp
+	ad.Feedback.RoughReached = rough
+	ad.Feedback.HighReached = high
+	ad.System.Load = load
+	ad.System.Hostname = hostname
+	return &ad
+}
+
 // httpIndex is the / view.
 func (d *daemon) httpIndex(w http.ResponseWriter, r *http.Request) {
 	if r.URL.Path != "/" {
@@ -57,33 +141,9 @@ func (d *daemon) httpIndex(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	volts, mbar := d.pirani()
-	rp := d.rpGet()
-	dp := d.dpGet()
-	safety := d.safetyStatusGet()
-
-	loadB, err := os.ReadFile("/proc/loadavg")
-	load := "unknown"
-	if err == nil {
-		parts := strings.Fields(string(loadB))
-		load = strings.Join(parts[:3], " ")
-	}
-
-	hostname, err := os.Hostname()
-	if err != nil {
-		hostname = "unknown"
-	}
-
-	templateIndex.Execute(w, map[string]any{
-		"failsafe":     safety.failsafe,
-		"highpressure": safety.highPressure,
-		"volts":        formatVolts(volts),
-		"mbar":         formatMbar(mbar),
-		"rp":           rp,
-		"dp":           dp,
-		"hostname":     hostname,
-		"load":         load,
-	})
+	data := d.apiData(false)
+	//data.Pirani.Mbar = html.St
+	templateIndex.Execute(w, data)
 }
 
 // httpStream is the websocket clientwards data hose, returning a 10Hz update
@@ -105,33 +165,7 @@ func (d *daemon) httpStream(w http.ResponseWriter, r *http.Request) {
 			c.Close(websocket.StatusNormalClosure, "")
 			return
 		case <-t.C:
-			// TODO(q3k): don't poll, get notified when new ADC readout is available.
-			volts, mbar := d.pirani()
-			rp := d.rpGet()
-			dp := d.dpGet()
-			rough, high := d.vacuumStatusGet()
-			safety := d.safetyStatusGet()
-			v := struct {
-				Failsafe     bool
-				HighPressure bool
-				Volts        string
-				Mbar         string
-				MbarFloat    float32
-				RPOn         bool
-				DPOn         bool
-				RoughReached bool
-				HighReached  bool
-			}{
-				Failsafe:     safety.failsafe,
-				HighPressure: safety.highPressure,
-				Volts:        formatVolts(volts),
-				Mbar:         string(formatMbar(mbar)),
-				MbarFloat:    mbar,
-				RPOn:         rp,
-				DPOn:         dp,
-				RoughReached: rough,
-				HighReached:  high,
-			}
+			v := d.apiData(true)
 			if err := wsjson.Write(ctx, c, v); err != nil {
 				klog.Errorf("Websocket write failed: %v", err)
 				return
diff --git a/succbone/succd/index.html b/succbone/succd/index.html
index 4d758be..e12c73a 100644
--- a/succbone/succd/index.html
+++ b/succbone/succd/index.html
@@ -59,25 +59,25 @@ td > span {
     <table>
         <tr>
             <th>Voltage</th>
-            <td id="volts" colspan="4">{{.volts}}</td>
+            <td id="volts" colspan="4">{{ .Pirani.Volts }}</td>
         </tr>
         <tr>
             <th>Pressure</th>
-            <td id="mbar" colspan="4">{{.mbar}}</td>
+            <td id="mbar" colspan="4">{{ .Pirani.Mbar }}</td>
         </tr>
         <tr>
             <th>Thresholds</th>
             <td>Rough:</td>
-            <td id="trough">...</td>
+            <td id="trough">{{ if .Feedback.RoughReached }}OK{{ else }}NOK{{ end }}</td>
             <td>High:</td>
-            <td id="thigh">...</td>
+            <td id="thigh">{{ if .Feedback.HighReached }}OK{{ else }}NOK{{ end }}</td>
         </tr>
         <tr>
             <th>Pumps</th>
             <td>RP:</td>
-            <td id="rp">{{ if .rp }}ON{{ else }}OFF{{ end }}</td>
+            <td id="rp">{{ if .Pumps.RPOn }}ON{{ else }}OFF{{ end }}</td>
             <td>DP:</td>
-            <td id="dp">{{ if .dp }}ON{{ else }}OFF{{ end }}</td>
+            <td id="dp">{{ if .Pumps.DPOn }}ON{{ else }}OFF{{ end }}</td>
         </tr>
         <tr>
             <th>Evac Control</th>
@@ -96,11 +96,11 @@ td > span {
         </tr>
         <tr>
             <th>Failsafe</th>
-            <td id="failsafe" colspan="4">OK</td>
+            <td id="failsafe" colspan="4">{{ if .Safety.Failsafe }}ON{{ else }}OFF{{ end }}</td>
         </tr>
         <tr>
             <th>Diffusion Pump Lockout</th>
-            <td id="highpressure" colspan="4">OK</td>
+            <td id="highpressure" colspan="4">{{ if .Safety.HighPressure }}ON{{ else }}OFF{{ end }}</td>
         </tr>
     </table>
 </p>
@@ -109,7 +109,7 @@ td > span {
 </p>
 
 <p style="font-style: italic; font-size: 12px; margin-top: 5em;">
-    {{.hostname}} | load: {{.load}} | <a href="/debug/pprof">pprof</a> | <a href="/metrics">metrics</a> | ws ping: <span id="ping">…</span>
+    {{ .System.Hostname }} | load: {{ .System.Load }} | <a href="/debug/pprof">pprof</a> | <a href="/metrics">metrics</a> | ws ping: <span id="ping">…</span>
 </p>
 
 <script>
@@ -288,50 +288,53 @@ window.addEventListener("load", (_) => {
         });
         socket.addEventListener("message", (event) => {
             const data = JSON.parse(event.data);
-            volts.innerHTML = data.Volts;
-            mbar.innerHTML = data.Mbar;
-            failsafe.innerHTML = data.Failsafe ? "ON" : "OFF";
-            if (data.Failsafe) {
-              failsafe.style = "background-color: #f06060";
+            volts.innerHTML = data.Pirani.Volts;
+            mbar.innerHTML = data.Pirani.Mbar;
+            if (data.Safety.Failsafe) {
+                failsafe.innerHTML = "ON";
+                failsafe.style = "background-color: #f06060";
             } else {
-              failsafe.style = "background-color: #60f060";
+                failsafe.innerHTML = "OFF";
+                failsafe.style = "background-color: #60f060";
             }
-            if (data.HighPressure) {
-              highpressure.innerHTML = "ON";
-              highpressure.style =  "background-color: #f06060";
+            if (data.Safety.HighPressure) {
+                highpressure.innerHTML = "ON";
+                highpressure.style =  "background-color: #f06060";
             } else {
-              highpressure.innerHTML = "OFF";
-              highpressure.style = "background-color: #60f060";
+                highpressure.innerHTML = "OFF";
+                highpressure.style = "background-color: #60f060";
             }
-            rp.innerHTML = data.RPOn ? "ON" : "OFF";
-            if (data.RPOn) {
+            if (data.Pumps.RPOn) {
+                rp.innerHTML = "ON";
                 rp.style = "background-color: #60f060";
             } else {
+                rp.innerHTML = "OFF";
                 rp.style = "background-color: #f06060";
             }
-            dp.innerHTML = data.DPOn ? "ON" : "OFF";
-            if (data.DPOn) {
+            if (data.Pumps.DPOn) {
+                dp.innerHTML = "ON";
                 dp.style = "background-color: #60f060";
             } else {
+                dp.innerHTML = "OFF";
                 dp.style = "background-color: #f06060";
             }
 
             let t = [];
-            if (data.RoughReached) {
+            if (data.Feedback.RoughReached) {
                 trough.innerHTML = "OK";
                 trough.style = "background-color: #60f060";
             } else {
                 trough.innerHTML = "NOK";
                 trough.style = "background-color: #f06060";
             }
-            if (data.HighReached) {
+            if (data.Feedback.HighReached) {
                 thigh.innerHTML = "OK";
                 thigh.style = "background-color: #60f060";
             } else {
                 thigh.innerHTML = "NOK";
                 thigh.style = "background-color: #f06060";
             }
-            historicalPush(data.MbarFloat);
+            historicalPush(data.Pirani.MbarFloat);
             ping.innerHTML = Date.now();
         });
         socket.addEventListener("close", (event) => {