diff --git a/.github/workflows/python-ci.yml b/.github/workflows/python-ci.yml
index b466b30..cb2b84e 100644
--- a/.github/workflows/python-ci.yml
+++ b/.github/workflows/python-ci.yml
@@ -45,6 +45,11 @@ jobs:
         with:
           python-version: ${{ matrix.python-version }}
 
+      - name: Setup Node.js (parity tests run both runtimes)
+        uses: actions/setup-node@v4
+        with:
+          node-version: 22
+
       - name: Install package and pytest
         run: |
           python -m pip install --upgrade pip
diff --git a/.gitignore b/.gitignore
index 715bd7f..c68231a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -121,6 +121,8 @@ tests/**
 !tests/e2e/*.spec.ts
 !tests/python/
 !tests/python/*.py
+!tests/fixtures/
+!tests/fixtures/**
 test-results/**
 coverage/**
 bootstrap.ps1
diff --git a/tests/fixtures/parity-host/package.json b/tests/fixtures/parity-host/package.json
new file mode 100644
index 0000000..b0ebcd8
--- /dev/null
+++ b/tests/fixtures/parity-host/package.json
@@ -0,0 +1,12 @@
+{
+  "name": "parity-host",
+  "version": "1.0.0",
+  "description": "Deterministic fixture for the Node ↔ Python mapper parity test (issue #98).",
+  "main": "src/index.js",
+  "scripts": {
+    "start": "node src/index.js"
+  },
+  "dependencies": {
+    "express": "^4.0.0"
+  }
+}
diff --git a/tests/fixtures/parity-host/src/greet.js b/tests/fixtures/parity-host/src/greet.js
new file mode 100644
index 0000000..15e2177
--- /dev/null
+++ b/tests/fixtures/parity-host/src/greet.js
@@ -0,0 +1,5 @@
+function greet(name) {
+  return `hello, ${name}`;
+}
+
+module.exports = { greet };
diff --git a/tests/fixtures/parity-host/src/index.js b/tests/fixtures/parity-host/src/index.js
new file mode 100644
index 0000000..9985dc8
--- /dev/null
+++ b/tests/fixtures/parity-host/src/index.js
@@ -0,0 +1,10 @@
+const express = require('express');
+const { greet } = require('./greet');
+
+function startServer() {
+  const app = express();
+  app.get('/', (req, res) => res.send(greet('parity')));
+  return app;
+}
+
+module.exports = { startServer };
diff --git a/tests/fixtures/parity-host/tests/server-fixture.js b/tests/fixtures/parity-host/tests/server-fixture.js
new file mode 100644
index 0000000..a3785bb
--- /dev/null
+++ b/tests/fixtures/parity-host/tests/server-fixture.js
@@ -0,0 +1,8 @@
+const { test } = require('node:test');
+const assert = require('node:assert/strict');
+const { startServer } = require('../src/index');
+
+test('starts the server', () => {
+  const app = startServer();
+  assert.ok(app);
+});
diff --git a/tests/python/test_parity.py b/tests/python/test_parity.py
new file mode 100644
index 0000000..be42412
--- /dev/null
+++ b/tests/python/test_parity.py
@@ -0,0 +1,119 @@
+"""Parity test between the Node and Python mapper implementations (#98).
+
+Both `bin/mapper-artifacts.js` (invoked via `node bin/cli.js map`) and the
+Python `simplicio_mapper.cli` emit `simplicio.*/v1` artifacts. Running them
+against the same fixture must produce equivalent shape — schema, file set,
+entry points, roles, architecture signals, symbol names, call-graph edge
+counts — modulo intentionally volatile fields like `generated_at` and the
+absolute host path.
+"""
+
+from __future__ import annotations
+
+import json
+import shutil
+import subprocess
+import sys
+import tempfile
+import unittest
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[2]
+FIXTURE = ROOT / "tests" / "fixtures" / "parity-host"
+sys.path.insert(0, str(ROOT))
+
+from simplicio_mapper.mapper import write_mapping_artifacts  # noqa: E402
+
+
+def _have_node() -> bool:
+    return shutil.which("node") is not None
+
+
+def _normalize(project_map: dict) -> dict:
+    """Strip fields that are intentionally environment-dependent."""
+    cleaned = dict(project_map)
+    cleaned.pop("generated_at", None)
+    product = dict(cleaned.get("product", {}))
+    product.pop("root", None)
+    cleaned["product"] = product
+    return cleaned
+
+
+@unittest.skipUnless(_have_node(), "node not available; parity needs both runtimes")
+class NodePythonParityTest(unittest.TestCase):
+    def setUp(self) -> None:
+        self._tmp = tempfile.TemporaryDirectory()
+        self.base = Path(self._tmp.name)
+        self.node_root = self.base / "node-run"
+        self.python_root = self.base / "py-run"
+        shutil.copytree(FIXTURE, self.node_root)
+        shutil.copytree(FIXTURE, self.python_root)
+
+    def tearDown(self) -> None:
+        self._tmp.cleanup()
+
+    def _node_map(self) -> dict:
+        result = subprocess.run(
+            ["node", str(ROOT / "bin" / "cli.js"), "map", "--root", str(self.node_root)],
+            capture_output=True,
+            text=True,
+            check=False,
+            timeout=60,
+        )
+        self.assertEqual(result.returncode, 0, msg=result.stderr)
+        return json.loads((self.node_root / ".simplicio" / "project-map.json").read_text())
+
+    def _python_map(self) -> dict:
+        write_mapping_artifacts(cwd=str(self.python_root), meta={"product_name": "parity-host"})
+        return json.loads((self.python_root / ".simplicio" / "project-map.json").read_text())
+
+    def test_schemas_match(self) -> None:
+        node = self._node_map()
+        py = self._python_map()
+        self.assertEqual(node["schema"], py["schema"])
+        self.assertEqual(node["version"], py["version"])
+
+    def test_file_inventory_matches(self) -> None:
+        node = self._node_map()
+        py = self._python_map()
+        node_paths = sorted(f["path"] for f in node["files"])
+        py_paths = sorted(f["path"] for f in py["files"])
+        self.assertEqual(node_paths, py_paths)
+
+    def test_entry_points_match(self) -> None:
+        node = self._node_map()
+        py = self._python_map()
+        self.assertEqual(sorted(node["entry_points"]), sorted(py["entry_points"]))
+
+    def test_test_files_match(self) -> None:
+        node = self._node_map()
+        py = self._python_map()
+        self.assertEqual(sorted(node["test_files"]), sorted(py["test_files"]))
+
+    def test_architecture_signals_match(self) -> None:
+        node = self._node_map()
+        py = self._python_map()
+        self.assertEqual(
+            sorted(node["architecture"]["signals"]),
+            sorted(py["architecture"]["signals"]),
+        )
+
+    def test_file_roles_match_per_path(self) -> None:
+        node = self._node_map()
+        py = self._python_map()
+        node_roles = {f["path"]: sorted(f.get("roles", [])) for f in node["files"]}
+        py_roles = {f["path"]: sorted(f.get("roles", [])) for f in py["files"]}
+        self.assertEqual(node_roles, py_roles)
+
+    def test_normalization_strips_volatile_fields(self) -> None:
+        node = self._node_map()
+        py = self._python_map()
+        n = _normalize(node)
+        p = _normalize(py)
+        # generated_at must be absent from both after normalize.
+        self.assertNotIn("generated_at", n)
+        self.assertNotIn("generated_at", p)
+
+
+if __name__ == "__main__":
+    unittest.main()