diff --git a/arbiter/arbiter-ui/src/main/java/org/deeplearning4j/arbiter/ui/module/ArbiterModule.java b/arbiter/arbiter-ui/src/main/java/org/deeplearning4j/arbiter/ui/module/ArbiterModule.java
index 6bcf3acbd..dab0174df 100644
--- a/arbiter/arbiter-ui/src/main/java/org/deeplearning4j/arbiter/ui/module/ArbiterModule.java
+++ b/arbiter/arbiter-ui/src/main/java/org/deeplearning4j/arbiter/ui/module/ArbiterModule.java
@@ -51,6 +51,7 @@ import org.deeplearning4j.ui.components.text.style.StyleText;
 import org.deeplearning4j.ui.i18n.I18NResource;
 import org.joda.time.format.DateTimeFormat;
 import org.joda.time.format.DateTimeFormatter;
+import org.nd4j.common.function.Function;
 import org.nd4j.common.primitives.Pair;
 import org.nd4j.shade.jackson.core.JsonProcessingException;
 
@@ -140,29 +141,89 @@ public class ArbiterModule implements UIModule {
                 (path, rc) -> rc.response().end(multiSession ? "true" : "false")));
         if (multiSession) {
             r.add(new Route("/arbiter", HttpMethod.GET, (path, rc) -> this.listSessions(rc)));
+            r.add(new Route("/arbiter/:sessionId", HttpMethod.GET, (path, rc) -> rc.response()
+                    .putHeader("content-type", "text/html; charset=utf-8")
+                    .sendFile("templates/ArbiterUI.html")));
+
+            r.add(new Route("/arbiter/:sessionId/lastUpdate", HttpMethod.GET, (path, rc) -> {
+                if (knownSessionIDs.containsKey(path.get(0))) {
+                    this.getLastUpdateTime(path.get(0), rc);
+                } else {
+                    sessionNotFound(path.get(0), rc.request().path(), rc);
+                }
+            }));
+            r.add(new Route("/arbiter/:sessionId/candidateInfo/:id", HttpMethod.GET, (path, rc) -> {
+                if (knownSessionIDs.containsKey(path.get(0))) {
+                    this.getCandidateInfo(path.get(0), path.get(1), rc);
+                } else {
+                    sessionNotFound(path.get(0), rc.request().path(), rc);
+                }
+            }));
+            r.add(new Route("/arbiter/:sessionId/config", HttpMethod.GET, (path, rc) -> {
+                if (knownSessionIDs.containsKey(path.get(0))) {
+                    this.getOptimizationConfig(path.get(0), rc);
+                } else {
+                    sessionNotFound(path.get(0), rc.request().path(), rc);
+                }
+            }));
+            r.add(new Route("/arbiter/:sessionId/results", HttpMethod.GET, (path, rc) -> {
+                if (knownSessionIDs.containsKey(path.get(0))) {
+                    this.getSummaryResults(path.get(0), rc);
+                } else {
+                    sessionNotFound(path.get(0), rc.request().path(), rc);
+                }
+            }));
+            r.add(new Route("/arbiter/:sessionId/summary", HttpMethod.GET, (path, rc) -> {
+                if (knownSessionIDs.containsKey(path.get(0))) {
+                    this.getSummaryStatus(path.get(0), rc);
+                } else {
+                    sessionNotFound(path.get(0), rc.request().path(), rc);
+                }
+            }));
         } else {
             r.add(new Route("/arbiter", HttpMethod.GET, (path, rc) -> rc.response()
                     .putHeader("content-type", "text/html; charset=utf-8")
                     .sendFile("templates/ArbiterUI.html")));
-            r.add(new Route("/arbiter/lastUpdate", HttpMethod.GET, (path, rc) -> this.getLastUpdateTime(rc)));
-            r.add(new Route("/arbiter/lastUpdate/:ids", HttpMethod.GET,
-                    (path, rc) -> this.getModelLastUpdateTimes(path.get(0), rc)));
+            r.add(new Route("/arbiter/lastUpdate", HttpMethod.GET, (path, rc) -> this.getLastUpdateTime(null, rc)));
             r.add(new Route("/arbiter/candidateInfo/:id", HttpMethod.GET,
-                    (path, rc) -> this.getCandidateInfo(path.get(0), rc)));
-            r.add(new Route("/arbiter/config", HttpMethod.GET, (path, rc) -> this.getOptimizationConfig(rc)));
-            r.add(new Route("/arbiter/results", HttpMethod.GET, (path, rc) -> this.getSummaryResults(rc)));
-            r.add(new Route("/arbiter/summary", HttpMethod.GET, (path, rc) -> this.getSummaryStatus(rc)));
+                    (path, rc) -> this.getCandidateInfo(null, path.get(0), rc)));
+            r.add(new Route("/arbiter/config", HttpMethod.GET, (path, rc) -> this.getOptimizationConfig(null, rc)));
+            r.add(new Route("/arbiter/results", HttpMethod.GET, (path, rc) -> this.getSummaryResults(null, rc)));
+            r.add(new Route("/arbiter/summary", HttpMethod.GET, (path, rc) -> this.getSummaryStatus(null, rc)));
 
-            r.add(new Route("/arbiter/sessions/all", HttpMethod.GET, (path, rc) -> this.sessionInfo(rc)));
             r.add(new Route("/arbiter/sessions/current", HttpMethod.GET, (path, rc) -> this.currentSession(rc)));
             r.add(new Route("/arbiter/sessions/set/:to", HttpMethod.GET,
                     (path, rc) -> this.setSession(path.get(0), rc)));
         }
+        // common for single- and multi-session mode
+        r.add(new Route("/arbiter/sessions/all", HttpMethod.GET, (path, rc) -> this.sessionInfo(rc)));
 
         return r;
     }
 
 
+    /**
+     * Load StatsStorage via provider, or return "not found"
+     *
+     * @param sessionId  session ID to look fo with provider
+     * @param targetPath one of overview / model / system, or null
+     * @param rc routing context
+     */
+    private void sessionNotFound(String sessionId, String targetPath, RoutingContext rc) {
+        Function<String, Boolean> loader = VertxUIServer.getInstance().getStatsStorageLoader();
+        if (loader != null && loader.apply(sessionId)) {
+            if (targetPath != null) {
+                rc.reroute(targetPath);
+            } else {
+                rc.response().end();
+            }
+        } else {
+            rc.response().setStatusCode(HttpResponseStatus.NOT_FOUND.code())
+                    .end("Unknown session ID: " + sessionId);
+        }
+    }
+
+
     /**
      * List optimization sessions. Returns a HTML list of arbiter sessions
      */
@@ -182,7 +243,7 @@ public class ArbiterModule implements UIModule {
         if (!knownSessionIDs.isEmpty()) {
             sb.append("        <ul>");
             for (String sessionId : knownSessionIDs.keySet()) {
-                sb.append("            <li><a href=\"train/")
+                sb.append("            <li><a href=\"arbiter/")
                         .append(sessionId).append("\">")
                         .append(sessionId).append("</a></li>\n");
             }
@@ -306,10 +367,25 @@ public class ArbiterModule implements UIModule {
 
     /**
      * Return the last update time for the page
+     * @param sessionId session ID (optional, for multi-session mode)
+     * @param rc routing context
      */
-    private void getLastUpdateTime(RoutingContext rc){
-        //TODO - this forces updates on every request... which is fine, just inefficient
-        long t = System.currentTimeMillis();
+    private void getLastUpdateTime(String sessionId, RoutingContext rc){
+        if (sessionId == null) {
+            sessionId = currentSessionID;
+        }
+        StatsStorage ss = knownSessionIDs.get(sessionId);
+        List<Persistable> latestUpdates = ss.getLatestUpdateAllWorkers(sessionId, ARBITER_UI_TYPE_ID);
+        long t = 0;
+        if (latestUpdates.isEmpty()) {
+            t = System.currentTimeMillis();
+        } else {
+            for (Persistable update : latestUpdates) {
+                if (update.getTimeStamp() > t) {
+                    t = update.getTimeStamp();
+                }
+            }
+        }
         UpdateStatus us = new UpdateStatus(t, t, t);
 
         rc.response().putHeader("content-type", "application/json").end(asJson(us));
@@ -323,56 +399,28 @@ public class ArbiterModule implements UIModule {
         }
     }
 
-    /**
-     * Get the last update time for the specified model IDs
-     * @param modelIDs Model IDs to get the update time for
-     */
-    private void getModelLastUpdateTimes(String modelIDs, RoutingContext rc){
-        if(currentSessionID == null){
-            rc.response().end();
-            return;
-        }
-
-        StatsStorage ss = knownSessionIDs.get(currentSessionID);
-        if(ss == null){
-            log.debug("getModelLastUpdateTimes(): Session ID is unknown: {}", currentSessionID);
-            rc.response().end("-1");
-            return;
-        }
-
-        String[] split = modelIDs.split(",");
-
-        long[] lastUpdateTimes = new long[split.length];
-        for( int i=0; i<split.length; i++ ){
-            String s = split[i];
-            Persistable p = ss.getLatestUpdate(currentSessionID, ARBITER_UI_TYPE_ID, s);
-            if(p != null){
-                lastUpdateTimes[i] = p.getTimeStamp();
-            }
-        }
-
-        rc.response().putHeader("content-type", "application/json").end(asJson(lastUpdateTimes));
-    }
-
     /**
      * Get the info for a specific candidate - last section in the UI
-     *
+     * @param sessionId session ID (optional, for multi-session mode)
      * @param candidateId ID for the candidate
+     * @param rc routing context
      */
-    private void getCandidateInfo(String candidateId, RoutingContext rc){
-
-        StatsStorage ss = knownSessionIDs.get(currentSessionID);
+    private void getCandidateInfo(String sessionId, String candidateId, RoutingContext rc){
+        if (sessionId == null) {
+            sessionId = currentSessionID;
+        }
+        StatsStorage ss = knownSessionIDs.get(sessionId);
         if(ss == null){
-            log.debug("getModelLastUpdateTimes(): Session ID is unknown: {}", currentSessionID);
+            log.debug("getModelLastUpdateTimes(): Session ID is unknown: {}", sessionId);
             rc.response().end();
             return;
         }
 
         GlobalConfigPersistable gcp = (GlobalConfigPersistable)ss
-                .getStaticInfo(currentSessionID, ARBITER_UI_TYPE_ID, GlobalConfigPersistable.GLOBAL_WORKER_ID);
+                .getStaticInfo(sessionId, ARBITER_UI_TYPE_ID, GlobalConfigPersistable.GLOBAL_WORKER_ID);
         OptimizationConfiguration oc = gcp.getOptimizationConfiguration();
 
-        Persistable p = ss.getLatestUpdate(currentSessionID, ARBITER_UI_TYPE_ID, candidateId);
+        Persistable p = ss.getLatestUpdate(sessionId, ARBITER_UI_TYPE_ID, candidateId);
         if(p == null){
             String title = "No results found for model " + candidateId + ".";
             ComponentText ct = new ComponentText.Builder(title,STYLE_TEXT_SZ12).build();
@@ -542,17 +590,21 @@ public class ArbiterModule implements UIModule {
 
     /**
      * Get the optimization configuration - second section in the page
+     * @param sessionId session ID (optional, for multi-session mode)
+     * @param rc routing context
      */
-    private void getOptimizationConfig(RoutingContext rc){
-
-        StatsStorage ss = knownSessionIDs.get(currentSessionID);
+    private void getOptimizationConfig(String sessionId, RoutingContext rc){
+        if (sessionId == null) {
+            sessionId = currentSessionID;
+        }
+        StatsStorage ss = knownSessionIDs.get(sessionId);
         if(ss == null){
-            log.debug("getOptimizationConfig(): Session ID is unknown: {}", currentSessionID);
+            log.debug("getOptimizationConfig(): Session ID is unknown: {}", sessionId);
             rc.response().end();
             return;
         }
 
-        Persistable p = ss.getStaticInfo(currentSessionID, ARBITER_UI_TYPE_ID, GlobalConfigPersistable.GLOBAL_WORKER_ID);
+        Persistable p = ss.getStaticInfo(sessionId, ARBITER_UI_TYPE_ID, GlobalConfigPersistable.GLOBAL_WORKER_ID);
 
         if(p == null){
             log.debug("No static info");
@@ -642,15 +694,23 @@ public class ArbiterModule implements UIModule {
         rc.response().putHeader("content-type", "application/json").end(asJson(cd));
     }
 
-    private void getSummaryResults(RoutingContext rc){
-        StatsStorage ss = knownSessionIDs.get(currentSessionID);
+    /**
+     * Get candidates summary results list - third section on the page: Results table
+     * @param sessionId session ID (optional, for multi-session mode)
+     * @param rc routing context
+     */
+    private void getSummaryResults(String sessionId, RoutingContext rc){
+        if (sessionId == null) {
+            sessionId = currentSessionID;
+        }
+        StatsStorage ss = knownSessionIDs.get(sessionId);
         if(ss == null){
-            log.debug("getSummaryResults(): Session ID is unknown: {}", currentSessionID);
+            log.debug("getSummaryResults(): Session ID is unknown: {}", sessionId);
             rc.response().end();
             return;
         }
 
-        List<Persistable> allModelInfoTemp = new ArrayList<>(ss.getLatestUpdateAllWorkers(currentSessionID, ARBITER_UI_TYPE_ID));
+        List<Persistable> allModelInfoTemp = new ArrayList<>(ss.getLatestUpdateAllWorkers(sessionId, ARBITER_UI_TYPE_ID));
         List<String[]> table = new ArrayList<>();
         for(Persistable per : allModelInfoTemp){
             ModelInfoPersistable mip = (ModelInfoPersistable)per;
@@ -663,16 +723,21 @@ public class ArbiterModule implements UIModule {
 
     /**
      * Get summary status information: first section in the page
+     * @param sessionId session ID (optional, for multi-session mode)
+     * @param rc routing context
      */
-    private void getSummaryStatus(RoutingContext rc){
-        StatsStorage ss = knownSessionIDs.get(currentSessionID);
+    private void getSummaryStatus(String sessionId, RoutingContext rc){
+        if (sessionId == null) {
+            sessionId = currentSessionID;
+        }
+        StatsStorage ss = knownSessionIDs.get(sessionId);
         if(ss == null){
-            log.debug("getOptimizationConfig(): Session ID is unknown: {}", currentSessionID);
+            log.debug("getOptimizationConfig(): Session ID is unknown: {}", sessionId);
             rc.response().end();
             return;
         }
 
-        Persistable p = ss.getStaticInfo(currentSessionID, ARBITER_UI_TYPE_ID, GlobalConfigPersistable.GLOBAL_WORKER_ID);
+        Persistable p = ss.getStaticInfo(sessionId, ARBITER_UI_TYPE_ID, GlobalConfigPersistable.GLOBAL_WORKER_ID);
 
         if(p == null){
             log.info("No static info");
@@ -692,7 +757,7 @@ public class ArbiterModule implements UIModule {
 
         //How to get this? query all model infos...
 
-        List<Persistable> allModelInfoTemp = new ArrayList<>(ss.getLatestUpdateAllWorkers(currentSessionID, ARBITER_UI_TYPE_ID));
+        List<Persistable> allModelInfoTemp = new ArrayList<>(ss.getLatestUpdateAllWorkers(sessionId, ARBITER_UI_TYPE_ID));
         List<ModelInfoPersistable> allModelInfo = new ArrayList<>();
         for(Persistable per : allModelInfoTemp){
             ModelInfoPersistable mip = (ModelInfoPersistable)per;
diff --git a/arbiter/arbiter-ui/src/test/java/org/deeplearning4j/arbiter/optimize/TestBasic.java b/arbiter/arbiter-ui/src/test/java/org/deeplearning4j/arbiter/optimize/TestBasic.java
index cb2374d64..025ce85c6 100644
--- a/arbiter/arbiter-ui/src/test/java/org/deeplearning4j/arbiter/optimize/TestBasic.java
+++ b/arbiter/arbiter-ui/src/test/java/org/deeplearning4j/arbiter/optimize/TestBasic.java
@@ -160,7 +160,7 @@ public class TestBasic extends BaseDL4JTest {
         UIServer uIServer = UIServer.getInstance(true, statsStorageProvider);
         String serverAddress = uIServer.getAddress();
         for (String sessionId : statsStorageForSession.keySet()) {
-            log.info("Arbiter session will start at {}/arbiter/{}", serverAddress, sessionId);
+            log.info("Arbiter session can be attached at {}/arbiter/{}", serverAddress, sessionId);
         }
 
         runner.execute();