diff --git a/jacodb-ets/src/main/kotlin/org/jacodb/ets/utils/BlockCfgToDot.kt b/jacodb-ets/src/main/kotlin/org/jacodb/ets/utils/BlockCfgToDot.kt
index 49f61afef..6f75b4b52 100644
--- a/jacodb-ets/src/main/kotlin/org/jacodb/ets/utils/BlockCfgToDot.kt
+++ b/jacodb-ets/src/main/kotlin/org/jacodb/ets/utils/BlockCfgToDot.kt
@@ -16,7 +16,15 @@
 
 package org.jacodb.ets.utils
 
+import org.jacodb.ets.model.BasicBlock
+import org.jacodb.ets.model.EtsAssignStmt
 import org.jacodb.ets.model.EtsBlockCfg
+import org.jacodb.ets.model.EtsCallExpr
+import org.jacodb.ets.model.EtsCallStmt
+import org.jacodb.ets.model.EtsStmt
+import java.nio.file.Files
+import java.nio.file.Path
+import java.nio.file.Paths
 
 private fun String.htmlEncode(): String = this
     .replace("&", "&")
@@ -24,7 +32,9 @@ private fun String.htmlEncode(): String = this
     .replace(">", ">")
     .replace("\"", """)
 
-fun EtsBlockCfg.toDot(useHtml: Boolean = true): String {
+fun EtsBlockCfg.toDot(
+    useHtml: Boolean = true
+): String {
     val lines = mutableListOf<String>()
     lines += "digraph cfg {"
     lines += "  node [shape=${if (useHtml) "none" else "rect"} fontname=\"monospace\"]"
@@ -65,3 +75,187 @@ fun EtsBlockCfg.toDot(useHtml: Boolean = true): String {
     lines += "}"
     return lines.joinToString("\n")
 }
+
+/**
+ * An interprocedural CFG that contains:
+ *  - the main control-flow graph (main)
+ *  - all callee CFGs discovered so far at call sites (keyed by statement and its parent block id)
+ */
+data class InterproceduralCfg(
+    val main: EtsBlockCfg,
+    val callees: Map<Pair<EtsStmt, Int>, EtsBlockCfg>
+)
+
+/**
+ * Render the interprocedural CFG (main + callees) as a single Graphviz DOT document,
+ * highlighting the execution path and current statement, and drawing
+ * each callee in its own dashed subgraph connected back to the call site.
+ */
+fun InterproceduralCfg.toHighlightedDotWithCalls(
+    pathStmts: Set<EtsStmt>,
+    currentStmt: EtsStmt?,
+    useHtml: Boolean = true
+): String {
+    val lines = mutableListOf<String>()
+    lines += "digraph world {"
+    lines += "  compound=true"
+    lines += "  node [shape=${if (useHtml) "none" else "rect"} fontname=\"monospace\"]"
+
+    // --- 1) Main CFG with ports on call statements ---
+    for (block in main.blocks) {
+        val nodeId = "M_${block.id}"
+        // compute all call hashes in this block
+        val callHashes = callees.keys
+            .filter { it.second == block.id }
+            .map { sanitize(it.first.hashCode()) }
+            .toSet()
+
+        if (useHtml) {
+            // build HTML table rows, adding port attribute on call lines
+            val rows = block.statements.joinToString(separator = "") { stmt ->
+                val txt = stmt.toDotLabel().htmlEncode()
+                val bg = when (stmt) {
+                    currentStmt -> "lightblue"
+                    in pathStmts -> "yellow"
+                    else -> "white"
+                }
+                val stmtHash = sanitize(stmt.hashCode())
+                val portAttr = if (stmtHash in callHashes) " port=\"p$stmtHash\"" else ""
+                "<tr><td balign=\"left\" bgcolor=\"$bg\"$portAttr>$txt</td></tr>"
+            }
+            val table = buildString {
+                append("<table border=\"0\" cellborder=\"1\" cellspacing=\"0\">")
+                append("<tr><td><b>Block #${block.id}</b></td></tr>")
+                append(rows)
+                append("</table>")
+            }
+            lines += "  $nodeId [label=<$table>];"
+        } else {
+            val lbl = buildPlainLabel(block, pathStmts, currentStmt)
+            lines += "  $nodeId [label=\"$lbl\"];"
+        }
+    }
+    // Main CFG edges
+    for ((bid, succs) in main.successors) {
+        val from = "M_$bid"
+        when (succs.size) {
+            1 -> lines += "  $from -> M_${succs[0]};"
+            2 -> {
+                val (t, f) = succs
+                lines += "  $from -> M_$t [label=\"true\"];"
+                lines += "  $from -> M_$f [label=\"false\"];"
+            }
+        }
+    }
+
+    // --- 2) Callee clusters with call-edge from port ---
+    for ((key, cfg) in callees) {
+        val (stmt, parentBlock) = key
+        val h = sanitize(stmt.hashCode())
+        val clusterName = "cluster_${h}_B${parentBlock}"
+        // method signature label
+        val methodSig = cfg.entries.first().method.signature
+        // open subgraph
+        lines += "  subgraph \"$clusterName\" {"
+        lines += "    label=\"$methodSig\";"
+        lines += "    style=dashed;"
+
+        // render callee nodes
+        for (blk in cfg.blocks) {
+            val calleeNode = "C_${h}_${blk.id}"
+            if (useHtml) {
+                val table = buildHtmlTable(blk, pathStmts, currentStmt)
+                lines += "    $calleeNode [label=<$table>];"
+            } else {
+                val lbl = buildPlainLabel(blk, pathStmts, currentStmt)
+                lines += "    $calleeNode [label=\"$lbl\"];"
+            }
+        }
+        // render callee edges
+        for ((bid, succs) in cfg.successors) {
+            val from = "C_${h}_$bid"
+            when (succs.size) {
+                1 -> lines += "    $from -> C_${h}_${succs[0]};"
+                2 -> {
+                    val (t, f) = succs
+                    lines += "    $from -> C_${h}_$t [label=\"true\"];"
+                    lines += "    $from -> C_${h}_$f [label=\"false\"];"
+                }
+            }
+        }
+        lines += "  }"
+
+        // connect from the specific port on the caller block
+        // connect from the specific port on the caller block using tailport
+        val caller = "M_${parentBlock}"
+        val entryId  = cfg.blocks.first().id
+        val calleeEntry = "C_${h}_$entryId"
+        val stmtHash = sanitize(stmt.hashCode())
+        lines += "  $caller:p$stmtHash -> $calleeEntry [tailport=\"p$stmtHash\" ltail=\"$clusterName\" lhead=\"$clusterName\" style=dotted label=\"call\"];"
+    }
+
+    lines += "}"
+    return lines.joinToString("\n")
+}
+
+private fun buildHtmlTable(
+    block: BasicBlock,
+    pathStmts: Set<EtsStmt>,
+    currentStmt: EtsStmt?
+): String {
+    var i = 0
+    val rows = block.statements.joinToString(separator = "") { stmt ->
+        val txt = stmt.toDotLabel().htmlEncode()
+        val stmtHash = sanitize(stmt.hashCode())
+        val portAttr = if (stmt.callExpr != null) " port=\"p$stmtHash\"" else ""
+
+        val bg = when (stmt) {
+            currentStmt -> "lightblue"
+            in pathStmts -> "yellow"
+            else -> "white"
+        }
+        i++
+        "<tr><td balign=\"left\" bgcolor=\"$bg\"$portAttr>$txt</td></tr>"
+    }
+    return "<table border=\"0\" cellborder=\"1\" cellspacing=\"0\">" +
+        "<tr><td><b>Block #${block.id}</b></td></tr>" + rows +
+        "</table>"
+}
+
+private fun buildPlainLabel(
+    block: BasicBlock,
+    pathStmts: Set<EtsStmt>,
+    currentStmt: EtsStmt?
+): String {
+    val body = block.statements.joinToString(separator = "") { stmt ->
+        val raw = stmt.toDotLabel()
+        val pfx = when (stmt) {
+            currentStmt -> "[▶] "
+            in pathStmts -> "[·] "
+            else -> ""
+        }
+        "$pfx$raw\\l"
+    }
+    return "Block #${block.id}\\n" + body
+}
+
+fun renderDotOverwrite(
+    dot: String,
+    outputDir: Path = Paths.get("."),
+    baseName: String = "interproc_cfg",
+    dotCmd: String = "dot",
+    viewerCmd: String = when {
+        System.getProperty("os.name").startsWith("Mac") -> "open"
+        System.getProperty("os.name").startsWith("Win") -> "cmd /c start"
+        else -> "xdg-open"
+    }
+) {
+    val dotFile = outputDir.resolve("$baseName.dot")
+    val outSvg = outputDir.resolve("$baseName.svg")
+    Files.write(dotFile, dot.toByteArray())
+    Runtime.getRuntime().exec("$dotCmd -Tsvg -o $outSvg $dotFile").waitFor()
+    Runtime.getRuntime().exec("$viewerCmd $outSvg").waitFor()
+}
+
+// helper to sanitize negative hash codes for Graphviz IDs
+fun sanitize(id: Int): String = id.toString().let { if (it.startsWith("-")) "N${it.substring(1)}" else it }