diff --git a/src/utils/executionUtil.ts b/src/utils/executionUtil.ts
index feed67cbc..3b061aa46 100644
--- a/src/utils/executionUtil.ts
+++ b/src/utils/executionUtil.ts
@@ -1,5 +1,9 @@
-import type { LGraph, LGraphNode, NodeId } from '@comfyorg/litegraph'
-import { LGraphEventMode } from '@comfyorg/litegraph'
+import type { LGraph, NodeId } from '@comfyorg/litegraph'
+import {
+  ExecutableNodeDTO,
+  LGraphEventMode,
+  SubgraphNode
+} from '@comfyorg/litegraph'
 
 import type {
   ComfyApiWorkflow,
@@ -74,20 +78,31 @@ export const graphToPrompt = async (
   workflow.extra ??= {}
   workflow.extra.frontendVersion = __COMFYUI_FRONTEND_VERSION__
 
+  const computedNodeDtos = graph
+    .computeExecutionOrder(false)
+    .map(
+      (node) =>
+        new ExecutableNodeDTO(
+          node,
+          [],
+          node instanceof SubgraphNode ? node : undefined
+        )
+    )
+
   let output: ComfyApiWorkflow = {}
   // Process nodes in order of execution
-  for (const outerNode of graph.computeExecutionOrder(false)) {
-    const skipNode =
+  for (const outerNode of computedNodeDtos) {
+    // Don't serialize muted nodes
+    if (
       outerNode.mode === LGraphEventMode.NEVER ||
       outerNode.mode === LGraphEventMode.BYPASS
-    const innerNodes =
-      !skipNode && outerNode.getInnerNodes
-        ? outerNode.getInnerNodes()
-        : [outerNode]
-    for (const node of innerNodes) {
+    ) {
+      continue
+    }
+
+    for (const node of outerNode.getInnerNodes()) {
       if (
         node.isVirtualNode ||
-        // Don't serialize muted nodes
         node.mode === LGraphEventMode.NEVER ||
         node.mode === LGraphEventMode.BYPASS
       ) {
@@ -120,58 +135,14 @@ export const graphToPrompt = async (
 
       // Store all node links
       for (const [i, input] of node.inputs.entries()) {
-        let parent: LGraphNode | null | undefined = node.getInputNode(i)
-        if (!parent) continue
+        const resolvedInput = node.resolveInput(i)
+        if (!resolvedInput) continue
 
-        let link = node.getInputLink(i)
-        while (
-          parent?.mode === LGraphEventMode.BYPASS ||
-          parent?.isVirtualNode
-        ) {
-          if (!link) break
-
-          if (parent.isVirtualNode) {
-            link = parent.getInputLink(link.origin_slot)
-            if (!link) break
-
-            parent = parent.isSubgraphNode()
-              ? parent.resolveSubgraphOutputLink(link.origin_slot)?.outputNode
-              : parent.getInputNode(link.target_slot)
-
-            if (!parent) break
-          } else if (!parent.inputs) {
-            // Maintains existing behaviour if parent.getInputLink is overriden
-            break
-          } else if (parent.mode === LGraphEventMode.BYPASS) {
-            // Bypass nodes by finding first input with matching type
-            const parentInputIndexes = Object.keys(parent.inputs).map(Number)
-            // Prioritise exact slot index
-            const indexes = [link.origin_slot].concat(parentInputIndexes)
-
-            const matchingIndex = indexes.find(
-              (index) => parent?.inputs[index]?.type === input.type
-            )
-            // No input types match
-            if (matchingIndex === undefined) break
-
-            link = parent.getInputLink(matchingIndex)
-            if (link) parent = parent.getInputNode(matchingIndex)
-          }
-        }
-
-        if (link) {
-          if (parent?.updateLink) {
-            // Subgraph node / groupNode callback; deprecated, should be replaced
-            link = parent.updateLink(link)
-          }
-          if (link) {
-            inputs[input.name] = [
-              String(link.origin_id),
-              // @ts-expect-error link.origin_slot is already number.
-              parseInt(link.origin_slot)
-            ]
-          }
-        }
+        inputs[input.name] = [
+          String(resolvedInput.origin_id),
+          // @ts-expect-error link.origin_slot is already number.
+          parseInt(resolvedInput.origin_slot)
+        ]
       }
 
       output[String(node.id)] = {
diff --git a/src/utils/litegraphUtil.ts b/src/utils/litegraphUtil.ts
index 865c4f6c6..738fbd7ca 100644
--- a/src/utils/litegraphUtil.ts
+++ b/src/utils/litegraphUtil.ts
@@ -1,6 +1,10 @@
 import { ColorOption, LGraph, Reroute } from '@comfyorg/litegraph'
 import { LGraphGroup, LGraphNode, isColorable } from '@comfyorg/litegraph'
-import type { ISerialisedGraph } from '@comfyorg/litegraph/dist/types/serialisation'
+import type {
+  ExportedSubgraph,
+  ISerialisableNodeInput,
+  ISerialisedGraph
+} from '@comfyorg/litegraph/dist/types/serialisation'
 import type {
   IBaseWidget,
   IComboWidget
@@ -167,12 +171,11 @@ export function fixLinkInputSlots(graph: LGraph) {
  * This should match the serialization format of legacy widget conversion.
  *
  * @param graph - The graph to compress widget input slots for.
+ * @throws If an infinite loop is detected.
  */
 export function compressWidgetInputSlots(graph: ISerialisedGraph) {
   for (const node of graph.nodes) {
-    node.inputs = node.inputs?.filter(
-      (input) => !(input.widget && input.link === null)
-    )
+    node.inputs = node.inputs?.filter(matchesLegacyApi)
 
     for (const [inputIndex, input] of node.inputs?.entries() ?? []) {
       if (input.link) {
@@ -183,4 +186,44 @@ export function compressWidgetInputSlots(graph: ISerialisedGraph) {
       }
     }
   }
+
+  compressSubgraphWidgetInputSlots(graph.definitions?.subgraphs)
+}
+
+function matchesLegacyApi(input: ISerialisableNodeInput) {
+  return !(input.widget && input.link === null)
+}
+
+/**
+ * Duplication to handle the legacy link arrays in the root workflow.
+ * @see compressWidgetInputSlots
+ * @param subgraph The subgraph to compress widget input slots for.
+ */
+function compressSubgraphWidgetInputSlots(
+  subgraphs: ExportedSubgraph[] | undefined,
+  visited = new WeakSet<ExportedSubgraph>()
+) {
+  if (!subgraphs) return
+
+  for (const subgraph of subgraphs) {
+    if (visited.has(subgraph)) throw new Error('Infinite loop detected')
+    visited.add(subgraph)
+
+    if (subgraph.nodes) {
+      for (const node of subgraph.nodes) {
+        node.inputs = node.inputs?.filter(matchesLegacyApi)
+
+        if (!subgraph.links) continue
+
+        for (const [inputIndex, input] of node.inputs?.entries() ?? []) {
+          if (input.link) {
+            const link = subgraph.links.find((link) => link.id === input.link)
+            if (link) link.target_slot = inputIndex
+          }
+        }
+      }
+    }
+
+    compressSubgraphWidgetInputSlots(subgraph.definitions?.subgraphs, visited)
+  }
 }