diff --git a/epdb/models.py b/epdb/models.py
index 55ca1dd9..d72576cb 100644
--- a/epdb/models.py
+++ b/epdb/models.py
@@ -2,6 +2,8 @@ import abc
 import json
 import logging
 import os
+import secrets
+import hashlib
 from collections import defaultdict
 from datetime import datetime, timedelta
 from typing import Union, List, Optional, Dict, Tuple, Set
@@ -58,27 +60,110 @@ class User(AbstractUser):
         return self.default_setting
 
 
-class APIToken(models.Model):
-    hashed_key = models.CharField(max_length=128, unique=True)
-    user = models.ForeignKey(User, on_delete=models.CASCADE)
-    created = models.DateTimeField(auto_now_add=True)
-    expires_at = models.DateTimeField(null=True, blank=True, default=timezone.now() + timedelta(days=90))
-    name = models.CharField(max_length=100, blank=True, help_text="Optional name for the token")
+class APIToken(TimeStampedModel):
+    """
+    API authentication token for users.
 
-    def is_valid(self):
-        return not self.expires_at or self.expires_at > timezone.now()
+    Provides secure token-based authentication with expiration support.
+    """
+    hashed_key = models.CharField(
+        max_length=128,
+        unique=True,
+        help_text="SHA-256 hash of the token key"
+    )
 
-    @staticmethod
-    def create_token(user, name="", valid_for=90):
-        import secrets
-        raw_token = secrets.token_urlsafe(32)
-        hashed = make_password(raw_token)
-        token = APIToken.objects.create(user=user, hashed_key=hashed, name=name,
-                                expires_at=timezone.now() + timedelta(days=valid_for))
-        return token, raw_token
+    user = models.ForeignKey(
+        User,
+        on_delete=models.CASCADE,
+        related_name='api_tokens',
+        help_text="User who owns this token"
+    )
 
-    def check_token(self, raw_token):
-        return check_password(raw_token, self.hashed_key)
+    expires_at = models.DateTimeField(
+        null=True,
+        blank=True,
+        help_text="Token expiration time (null for no expiration)"
+    )
+
+    name = models.CharField(
+        max_length=100,
+        help_text="Descriptive name for this token"
+    )
+
+    is_active = models.BooleanField(
+        default=True,
+        help_text="Whether this token is active"
+    )
+
+    class Meta:
+        db_table = 'epdb_api_token'
+        verbose_name = 'API Token'
+        verbose_name_plural = 'API Tokens'
+        ordering = ['-created']
+
+    def __str__(self) -> str:
+        return f"{self.name} ({self.user.username})"
+
+    def is_valid(self) -> bool:
+        """Check if token is valid and not expired."""
+        if not self.is_active:
+            return False
+
+        if self.expires_at and timezone.now() > self.expires_at:
+            return False
+
+        return True
+
+    @classmethod
+    def create_token(cls, user: User, name: str, expires_days: Optional[int] = None) -> Tuple['APIToken', str]:
+        """
+        Create a new API token for a user.
+
+        Args:
+            user: User to create token for
+            name: Descriptive name for the token
+            expires_days: Number of days until expiration (None for no expiration)
+
+        Returns:
+            Tuple of (token_instance, raw_key)
+        """
+        raw_key = secrets.token_urlsafe(32)
+        hashed_key = hashlib.sha256(raw_key.encode()).hexdigest()
+
+        expires_at = None
+        if expires_days:
+            expires_at = timezone.now() + timezone.timedelta(days=expires_days)
+
+        token = cls.objects.create(
+            user=user,
+            name=name,
+            hashed_key=hashed_key,
+            expires_at=expires_at
+        )
+
+        return token, raw_key
+
+    @classmethod
+    def authenticate(cls, raw_key: str) -> Optional[User]:
+        """
+        Authenticate a user using an API token.
+
+        Args:
+            raw_key: Raw token key
+
+        Returns:
+            User if token is valid, None otherwise
+        """
+        hashed_key = hashlib.sha256(raw_key.encode()).hexdigest()
+
+        try:
+            token = cls.objects.select_related('user').get(hashed_key=hashed_key)
+            if token.is_valid():
+                return token.user
+        except cls.DoesNotExist:
+            pass
+
+        return None
 
 
 class Group(TimeStampedModel):
@@ -1090,16 +1175,15 @@ class Node(EnviPathModel, AliasMixin, ScenarioMixin):
         data = self.kv.get('app_domain_assessment', None)
 
         if data:
-            rule_ids = dict()
+            rule_ids = defaultdict(list)
             for e in Edge.objects.filter(start_nodes__in=[self]):
                 for r in e.edge_label.rules.all():
-                    rule_ids[str(r.uuid)] = e
-
+                    rule_ids[str(r.uuid)].append(e.simple_json())
 
             for t in data['assessment']['transformations']:
                 if t['rule']['uuid'] in rule_ids:
                     t['is_predicted'] = True
-                    t['edge'] = rule_ids[t['rule']['uuid']].simple_json()
+                    t['edges'] = rule_ids[t['rule']['uuid']]
 
         return data
 
@@ -1141,23 +1225,25 @@ class Edge(EnviPathModel, AliasMixin, ScenarioMixin):
 
             if app_domain_data:
                 for t in app_domain_data['assessment']['transformations']:
-                    if 'edge' in t and t['edge']['uuid'] == str(self.uuid):
-                        passes_app_domain = (
-                                t['local_compatibility'] >= app_domain_data['ad_params']['local_compatibility_threshold']
-                        ) and (
-                            t['reliability'] >= app_domain_data['ad_params']['reliability_threshold']
-                        )
+                    if 'edges' in t:
+                        for e in t['edges']:
+                            if e['uuid'] == str(self.uuid):
+                                passes_app_domain = (
+                                        t['local_compatibility'] >= app_domain_data['ad_params']['local_compatibility_threshold']
+                                ) and (
+                                    t['reliability'] >= app_domain_data['ad_params']['reliability_threshold']
+                                )
 
-                        edge_json['app_domain'] = {
-                            'passes_app_domain': passes_app_domain,
-                            'local_compatibility': t['local_compatibility'],
-                            'local_compatibility_threshold': app_domain_data['ad_params']['local_compatibility_threshold'],
-                            'reliability': t['reliability'],
-                            'reliability_threshold': app_domain_data['ad_params']['reliability_threshold'],
-                            'times_triggered': t['times_triggered'],
-                        }
+                                edge_json['app_domain'] = {
+                                    'passes_app_domain': passes_app_domain,
+                                    'local_compatibility': t['local_compatibility'],
+                                    'local_compatibility_threshold': app_domain_data['ad_params']['local_compatibility_threshold'],
+                                    'reliability': t['reliability'],
+                                    'reliability_threshold': app_domain_data['ad_params']['reliability_threshold'],
+                                    'times_triggered': t['times_triggered'],
+                                }
 
-                        break
+                                break
 
         return edge_json
 
diff --git a/static/js/pps.js b/static/js/pps.js
index d6f064d4..d2f7971a 100644
--- a/static/js/pps.js
+++ b/static/js/pps.js
@@ -739,7 +739,10 @@ function handleAssessmentResponse(depict_url, data) {
         var objLink = null;
         if (transObj['is_predicted']) {
             panelName = `Predicted Transformation by ${transObj['rule']['name']}`;
-            objLink = `<a class='list-group-item' href="${transObj['edge']['url']}">${transObj['edge']['name']}</a>`
+            for (e in transObj['edges']) {
+                objLink = `<a class='list-group-item' href="${transObj['edges'][e]['url']}">${transObj['edges'][e]['name']}</a>`
+                break;
+            }
         } else {
             panelName = `Potential Transformation by applying ${transObj['rule']['name']}`;
             objLink = `<a class='list-group-item' href="${transObj['rule']['url']}">${transObj['rule']['name']}</a>`
diff --git a/static/js/pw.js b/static/js/pw.js
index 5e362d12..99c44595 100644
--- a/static/js/pw.js
+++ b/static/js/pw.js
@@ -1,6 +1,5 @@
 console.log("loaded pw.js")
 
-
 function predictFromNode(url) {
     $.post("", {node: url})
         .done(function (data) {
@@ -28,62 +27,165 @@ function draw(pathway, elem) {
         const horizontalSpacing = 75; // horizontal space between nodes
         const depthMap = new Map();
 
-        nodes.forEach(node => {
+        // Sort nodes by depth first to minimize crossings
+        const sortedNodes = [...nodes].sort((a, b) => a.depth - b.depth);
+
+        sortedNodes.forEach(node => {
             if (!depthMap.has(node.depth)) {
                 depthMap.set(node.depth, 0);
             }
 
             const nodesInLevel = nodes.filter(n => n.depth === node.depth).length;
-            node.fx = width / 2 + depthMap.get(node.depth) * horizontalSpacing - ((nodesInLevel - 1) * horizontalSpacing) / 2;
-            node.fy = node.depth * levelSpacing + 50;
 
+            // For pseudo nodes, try to position them to minimize crossings
+            if (node.pseudo) {
+                const parentLinks = links.filter(l => l.target.id === node.id);
+                const childLinks = links.filter(l => l.source.id === node.id);
+
+                if (parentLinks.length > 0 && childLinks.length > 0) {
+                    const parentX = parentLinks[0].source.x || (width / 2);
+                    const childrenX = childLinks.map(l => l.target.x || (width / 2));
+                    const avgChildX = childrenX.reduce((sum, x) => sum + x, 0) / childrenX.length;
+
+                    // Position pseudo node between parent and average child position
+                    node.fx = (parentX + avgChildX) / 2;
+                } else {
+                    node.fx = width / 2 + depthMap.get(node.depth) * horizontalSpacing - ((nodesInLevel - 1) * horizontalSpacing) / 2;
+                }
+            } else {
+                node.fx = width / 2 + depthMap.get(node.depth) * horizontalSpacing - ((nodesInLevel - 1) * horizontalSpacing) / 2;
+            }
+
+            node.fy = node.depth * levelSpacing + 50;
             depthMap.set(node.depth, depthMap.get(node.depth) + 1);
         });
     }
 
-    // Funktion für das Update der Positionen
+    // Function to update pseudo node positions based on connected nodes
+    function updatePseudoNodePositions() {
+        nodes.forEach(node => {
+            if (node.pseudo && !node.isDragging) { // Don't auto-update if being dragged
+                const parentLinks = links.filter(l => l.target.id === node.id);
+                const childLinks = links.filter(l => l.source.id === node.id);
+
+                if (parentLinks.length > 0 && childLinks.length > 0) {
+                    const parent = parentLinks[0].source;
+                    const children = childLinks.map(l => l.target);
+
+                    // Calculate optimal position to minimize crossing
+                    const parentX = parent.x;
+                    const parentY = parent.y;
+                    const childrenX = children.map(c => c.x);
+                    const childrenY = children.map(c => c.y);
+                    const avgChildX = d3.mean(childrenX);
+                    const avgChildY = d3.mean(childrenY);
+
+                    // Position pseudo node between parent and average child position
+                    node.fx = (parentX + avgChildX) / 2;
+                    node.fy = (parentY + avgChildY) / 2; // Allow vertical movement too
+                }
+            }
+        });
+    }
+
+
+    // Enhanced ticked function
     function ticked() {
+        // Update pseudo node positions first
+        updatePseudoNodePositions();
+
         link.attr("x1", d => d.source.x)
             .attr("y1", d => d.source.y)
             .attr("x2", d => d.target.x)
             .attr("y2", d => d.target.y);
 
         node.attr("transform", d => `translate(${d.x},${d.y})`);
-
-        nodes.forEach(n => {
-            if (n.pseudo) {
-                // Alle Kinder dieses Pseudonodes finden
-                const childLinks = links.filter(l => l.source.id === n.id);
-                const childNodes = childLinks.map(l => l.target);
-                if (childNodes.length > 0) {
-                    // Durchschnitt der Kinderpositionen berechnen
-                    const avgX = d3.mean(childNodes, d => d.x);
-                    const avgY = d3.mean(childNodes, d => d.y);
-                    n.fx = avgX;
-                    // keep level as is
-                    n.fy = n.y;
-                }
-            }
-        });
-        //simulation.alpha(0.3).restart();
     }
 
     function dragstarted(event, d) {
         if (!event.active) simulation.alphaTarget(0.3).restart();
-        d.fx = d.x; // Setzt die Fixierung auf die aktuelle Position
+        d.fx = d.x;
         d.fy = d.y;
+
+        // Mark if this node is being dragged
+        d.isDragging = true;
+
+        // If dragging a non-pseudo node, mark connected pseudo nodes for update
+        if (!d.pseudo) {
+            markConnectedPseudoNodes(d);
+        }
     }
 
     function dragged(event, d) {
-        d.fx = event.x; // Position direkt an Maus anpassen
+        d.fx = event.x;
         d.fy = event.y;
+
+        // Update connected pseudo nodes in real-time
+        if (!d.pseudo) {
+            updateConnectedPseudoNodes(d);
+        }
     }
 
     function dragended(event, d) {
         if (!event.active) simulation.alphaTarget(0);
-        // Knoten bleibt an der neuen Position und wird nicht zurückgezogen
+
+        // Mark that dragging has ended
+        d.isDragging = false;
+
+        // Final update of connected pseudo nodes
+        if (!d.pseudo) {
+            updateConnectedPseudoNodes(d);
+        }
     }
 
+    // Helper function to mark connected pseudo nodes
+    function markConnectedPseudoNodes(draggedNode) {
+        // Find pseudo nodes connected to this node
+        const connectedPseudos = new Set();
+
+        // Check as parent of pseudo nodes
+        links.filter(l => l.source.id === draggedNode.id && l.target.pseudo)
+            .forEach(l => connectedPseudos.add(l.target));
+
+        // Check as child of pseudo nodes
+        links.filter(l => l.target.id === draggedNode.id && l.source.pseudo)
+            .forEach(l => connectedPseudos.add(l.source));
+
+        return connectedPseudos;
+    }
+
+    // Helper function to update connected pseudo nodes
+    function updateConnectedPseudoNodes(draggedNode) {
+        const connectedPseudos = markConnectedPseudoNodes(draggedNode);
+
+        connectedPseudos.forEach(pseudoNode => {
+            if (!pseudoNode.isDragging) { // Don't update if pseudo node is being dragged
+                const parentLinks = links.filter(l => l.target.id === pseudoNode.id);
+                const childLinks = links.filter(l => l.source.id === pseudoNode.id);
+
+                if (parentLinks.length > 0 && childLinks.length > 0) {
+                    const parent = parentLinks[0].source;
+                    const children = childLinks.map(l => l.target);
+
+                    const parentX = parent.fx || parent.x;
+                    const parentY = parent.fy || parent.y;
+                    const childrenX = children.map(c => c.fx || c.x);
+                    const childrenY = children.map(c => c.fy || c.y);
+                    const avgChildX = d3.mean(childrenX);
+                    const avgChildY = d3.mean(childrenY);
+
+                    // Update pseudo node position - allow both X and Y movement
+                    pseudoNode.fx = (parentX + avgChildX) / 2;
+                    pseudoNode.fy = (parentY + avgChildY) / 2;
+                }
+            }
+        });
+
+        // Restart simulation with lower alpha to smooth the transition
+        simulation.alpha(0.1).restart();
+    }
+
+
     // t -> ref to "this" from d3
     function nodeClick(event, node, t) {
         console.log(node);
@@ -105,7 +207,7 @@ function draw(pathway, elem) {
                 pop = $(e).attr("aria-describedby")
                 h = $('#' + pop).height();
                 $('#' + pop).attr("style", `position: fixed; top: ${clientY - (h / 2.0)}px; left: ${clientX + 10}px; margin: 0px; max-width: 1000px; display: block;`)
-            setTimeout(function () {
+                setTimeout(function () {
                     var close = setInterval(function () {
                         if (!$(".popover:hover").length // mouse outside popover
                             && !$(e).is(':hover')) { // mouse outside element
@@ -140,13 +242,12 @@ function draw(pathway, elem) {
         });
     }
 
-
     function node_popup(n) {
-        popupContent = "<a href='" + n.url +"'>" + n.name + "</a><br>";
+        popupContent = "<a href='" + n.url + "'>" + n.name + "</a><br>";
         popupContent += "Depth " + n.depth + "<br>"
 
         if (appDomainViewEnabled) {
-            if(n.app_domain != null) {
+            if (n.app_domain != null) {
                 popupContent += "This compound is " + (n.app_domain['inside_app_domain'] ? "inside" : "outside") + " the Applicability Domain derived from the chemical (PCA) space constructed using the training data." + "<br>"
                 if (n.app_domain['uncovered_functional_groups']) {
                     popupContent += "Compound contains functional groups not covered by the training set  <br>"
@@ -154,7 +255,7 @@ function draw(pathway, elem) {
             }
         }
 
-        popupContent += "<img src='" + n.image + "' width='"+ 20 * nodeRadius +"'><br>"
+        popupContent += "<img src='" + n.image + "' width='" + 20 * nodeRadius + "'><br>"
         if (n.scenarios.length > 0) {
             popupContent += '<b>Half-lives and related scenarios:</b><br>'
             for (var s of n.scenarios) {
@@ -163,7 +264,7 @@ function draw(pathway, elem) {
         }
 
         var isLeaf = pathway.links.filter(obj => obj.source.id === n.id).length === 0;
-        if(pathway.isIncremental && isLeaf) {
+        if (pathway.isIncremental && isLeaf) {
             popupContent += '<br><a class="btn btn-primary" onclick="predictFromNode(\'' + n.url + '\')" href="#">Predict from here</a><br>';
         }
 
@@ -171,25 +272,24 @@ function draw(pathway, elem) {
     }
 
     function edge_popup(e) {
-        popupContent = "<a href='" + e.url +"'>" + e.name + "</a><br>";
+        popupContent = "<a href='" + e.url + "'>" + e.name + "</a><br>";
 
-        if(e.app_domain){
+        if (e.app_domain) {
             adcontent = "<p>";
-            if(e.app_domain["times_triggered"]) {
+            if (e.app_domain["times_triggered"]) {
                 adcontent += "This rule triggered " + e.app_domain["times_triggered"] + " times in the training set<br>";
             }
-            adcontent += "Reliability " + e.app_domain["reliability"].toFixed(2) + " (" + (e.app_domain["reliability"] > e.app_domain["reliability_threshold"] ? "&gt" : "&lt") + " Reliability Threshold of " +  e.app_domain["reliability_threshold"] + ")<br>";
-            adcontent += "Local Compatibility " + e.app_domain["local_compatibility"].toFixed(2) + " (" + (e.app_domain["local_compatibility"] > e.app_domain["local_compatibility_threshold"] ? "&gt" : "&lt") + " Local Compatibility Threshold of " +  e.app_domain["local_compatibility_threshold"] + ")<br>";
+            adcontent += "Reliability " + e.app_domain["reliability"].toFixed(2) + " (" + (e.app_domain["reliability"] > e.app_domain["reliability_threshold"] ? "&gt" : "&lt") + " Reliability Threshold of " + e.app_domain["reliability_threshold"] + ")<br>";
+            adcontent += "Local Compatibility " + e.app_domain["local_compatibility"].toFixed(2) + " (" + (e.app_domain["local_compatibility"] > e.app_domain["local_compatibility_threshold"] ? "&gt" : "&lt") + " Local Compatibility Threshold of " + e.app_domain["local_compatibility_threshold"] + ")<br>";
             adcontent += "</p>";
+            popupContent += adcontent;
         }
-        popupContent += adcontent;
 
-        popupContent += "<img src='" + e.image + "' width='"+ 20 * nodeRadius +"'><br>"
+        popupContent += "<img src='" + e.image + "' width='" + 20 * nodeRadius + "'><br>"
         if (e.reaction_probability) {
             popupContent += '<b>Probability:</b><br>' + e.reaction_probability.toFixed(3) + '<br>';
         }
 
-
         if (e.scenarios.length > 0) {
             popupContent += '<b>Half-lives and related scenarios:</b><br>'
             for (var s of e.scenarios) {
@@ -202,9 +302,9 @@ function draw(pathway, elem) {
 
     var clientX;
     var clientY;
-    document.addEventListener('mousemove', function(event) {
+    document.addEventListener('mousemove', function (event) {
         clientX = event.clientX;
-        clientY =event.clientY;
+        clientY = event.clientY;
     });
 
     const zoomable = d3.select("#zoomable");
@@ -258,8 +358,8 @@ function draw(pathway, elem) {
         .attr("marker-end", d => d.target.pseudo ? '' : 'url(#arrow)')
 
     // add element to links array
-    link.each(function(d) {
-      d.el = this;  // attach the DOM element to the data object
+    link.each(function (d) {
+        d.el = this;  // attach the DOM element to the data object
     });
 
     pop_add(link, "Reaction", edge_popup);
@@ -279,7 +379,7 @@ function draw(pathway, elem) {
 
     // Kreise für die Knoten hinzufügen
     node.append("circle")
-        // make radius "invisible"
+        // make radius "invisible" for pseudo nodes
         .attr("r", d => d.pseudo ? 0.01 : nodeRadius)
         .style("fill", "#e8e8e8");
 
@@ -292,9 +392,9 @@ function draw(pathway, elem) {
         .attr("height", nodeRadius * 2);
 
     // add element to nodes array
-    node.each(function(d) {
-      d.el = this;  // attach the DOM element to the data object
+    node.each(function (d) {
+        d.el = this;  // attach the DOM element to the data object
     });
 
     pop_add(node, "Compound", node_popup);
-}
+}
\ No newline at end of file
diff --git a/utilities/chem.py b/utilities/chem.py
index 395e65b1..6b3f7cea 100644
--- a/utilities/chem.py
+++ b/utilities/chem.py
@@ -639,20 +639,23 @@ class IndigoUtils(object):
                         environment.add(mappedAtom.index())
 
         for k, v in functional_groups.items():
+            try:
+                sanitized = IndigoUtils.sanitize_functional_group(k)
 
-            sanitized = IndigoUtils.sanitize_functional_group(k)
+                query = indigo.loadSmarts(sanitized)
 
-            query = indigo.loadSmarts(sanitized)
+                for match in matcher.iterateMatches(query):
+                    if match is not None:
 
-            for match in matcher.iterateMatches(query):
-                if match is not None:
+                        for atom in query.iterateAtoms():
+                            mappedAtom = match.mapAtom(atom)
+                            if mappedAtom is None or mappedAtom.index() in environment:
+                                continue
 
-                    for atom in query.iterateAtoms():
-                        mappedAtom = match.mapAtom(atom)
-                        if mappedAtom is None or mappedAtom.index() in environment:
-                            continue
+                            counts[mappedAtom.index()] = max(v, counts[mappedAtom.index()])
 
-                        counts[mappedAtom.index()] = max(v, counts[mappedAtom.index()])
+            except IndigoException as e:
+                logger.debug(f'Colorizing failed due to {e}')
 
         for k, v in counts.items():
             if is_reaction: