diff --git a/examples/webapp/app.py b/examples/webapp/app.py
index 839e197..9daf556 100644
--- a/examples/webapp/app.py
+++ b/examples/webapp/app.py
@@ -1,9 +1,11 @@
 #!/usr/bin/env python3
 
-from flask import Flask, jsonify, make_response, redirect, render_template, request
+from flask import Flask, jsonify, make_response, redirect, render_template, request, send_file
+import os
+import tempfile
 
 import pseudol10nutil.transforms as xforms
-from pseudol10nutil import PseudoL10nUtil
+from pseudol10nutil import PseudoL10nUtil, POFileUtil
 
 app = Flask(__name__)
 appname = "pseudol10nutil"
@@ -106,5 +108,69 @@ def do_pseudo_ui():
         return render_template("pseudolocalize_template.html", **default_options)
 
 
+@app.route(ui_base_url + "po_upload", methods=["POST"])
+def do_pseudo_po_upload():
+    input_temp_file_path = None
+    output_temp_file_path = None
+    try:
+        if "po_file" not in request.files:
+            return make_response(
+                jsonify({"error": "400 Error: No file part in the request."}), 400
+            )
+
+        file = request.files["po_file"]
+
+        if file.filename == "":
+            return make_response(
+                jsonify({"error": "400 Error: No file selected for uploading."}), 400
+            )
+
+        if not file.filename.endswith(".po"):
+            return make_response(
+                jsonify(
+                    {"error": "400 Error: Invalid file type. Please upload a .po file."}
+                ),
+                400,
+            )
+
+        # Create temporary files
+        fd_input, input_temp_file_path = tempfile.mkstemp(suffix=".po")
+        os.close(fd_input) # close file descriptor as pofileutil will open and close the file
+        fd_output, output_temp_file_path = tempfile.mkstemp(suffix=".po")
+        os.close(fd_output) # close file descriptor as pofileutil will open and close the file
+
+
+        file.save(input_temp_file_path)
+
+        pofileutil = POFileUtil()
+        # Apply the same transforms as the UI text input for consistency
+        # Default to diacritics, square brackets, and padding
+        # This could be made configurable in the UI later if needed
+        current_transforms = [
+            xforms.transliterate_diacritic,
+            xforms.pad_length,
+            xforms.square_brackets
+        ]
+        pofileutil.transforms = current_transforms
+        pofileutil.pseudolocalizefile(input_temp_file_path, output_temp_file_path)
+
+        return send_file(
+            output_temp_file_path,
+            as_attachment=True,
+            download_name="pseudolocalized.po",
+            mimetype="application/x-po",
+        )
+    except Exception as e:
+        # Log the exception e for debugging if necessary
+        return make_response(
+            jsonify({"error": f"500 Error: Internal server error during processing. {str(e)}"}), 500
+        )
+    finally:
+        if input_temp_file_path and os.path.exists(input_temp_file_path):
+            os.remove(input_temp_file_path)
+        if output_temp_file_path and os.path.exists(output_temp_file_path):
+            os.remove(output_temp_file_path)
+
+
 if __name__ == "__main__":
     app.run(host="0.0.0.0", debug=True)
diff --git a/examples/webapp/templates/pseudolocalize_template.html b/examples/webapp/templates/pseudolocalize_template.html
index c8c9517..8ec96e0 100644
--- a/examples/webapp/templates/pseudolocalize_template.html
+++ b/examples/webapp/templates/pseudolocalize_template.html
@@ -48,5 +48,13 @@ <h3 class="centered">Pseudo-localization options:</h3>
     <br />
     <textarea id="pseudolocalize_output" name="pseudolocalize_output" readonly>{{ pseudolocalized_text_output }}</textarea>
   </form>
+  <form class="centered" id="pseudolocalize_po_form" method="post" action="/pseudol10nutil/po_upload" enctype="multipart/form-data">
+    <h2 class="centered">Pseudolocalize PO File</h2>
+    <label for="po_file_input">PO file to pseudo-localize:</label>
+    <br />
+    <input type="file" id="po_file_input" name="po_file" accept=".po" />
+    <br />
+    <input type="submit" name="do_pseudolocalize_po" id="do_pseudolocalize_po" value="Pseudolocalize PO File"/>
+  </form>
 </body>
 </html>
diff --git a/examples/webapp/test_app.py b/examples/webapp/test_app.py
index cdcd380..9d2bc99 100644
--- a/examples/webapp/test_app.py
+++ b/examples/webapp/test_app.py
@@ -1,18 +1,27 @@
 import unittest
+import io
+import json
 
-import requests
+from examples.webapp.app import app, ui_base_url, api_base_url
+from src.pseudol10nutil.pseudol10nutil import PseudoL10nUtil
+from src.pseudol10nutil import transforms as xforms
 
-from pseudol10nutil import PseudoL10nUtil
 
-base_url = "http://localhost:5000/pseudol10nutil/api/v1.0/"
-headers = {"Accept": "application/json", "Content-Type": "application/json"}
-
-
-class TestPseudoL10nUtil(unittest.TestCase):
+class TestWebApp(unittest.TestCase):
     def setUp(self):
+        self.client = app.test_client()
+        # Keep util if other tests directly use its methods,
+        # or for comparing results in API tests.
         self.util = PseudoL10nUtil()
+        # Default transforms for PO file for assertion comparison
+        # This should match the defaults set in app.py's po_upload route
+        self.util.transforms = [
+            xforms.transliterate_diacritic,
+            xforms.pad_length,
+            xforms.square_brackets
+        ]
 
-    def test_pseudo(self):
+    def test_pseudo_api(self):
         data = {
             "key1": "The quick brown fox jumps over the lazy dog.",
             "key2": "The quick brown {animal1} jumps over the lazy {animal2}.",
@@ -20,10 +29,84 @@ def test_pseudo(self):
             "key4": "The quick brown %(animal1)s jumps over the lazy %(animal2)s.",
         }
         request_data = {"strings": data}
-        resp = requests.post(base_url + "pseudo", headers=headers, json=request_data)
-        results = resp.json()["strings"]
+        # Reset transforms to default for this specific API test if needed,
+        # as self.util might be configured with PO file defaults in setUp.
+        # For this test, we use a fresh PseudoL10nUtil instance with its own default transforms.
+        fresh_util_for_api_test = PseudoL10nUtil()
+        # If the main API also uses specific non-default transforms, set them here for fresh_util_for_api_test
+        # For now, assuming it uses the class defaults.
+
+        resp = self.client.post(
+            api_base_url + "pseudo",
+            headers={"Content-Type": "application/json", "Accept": "application/json"},
+            data=json.dumps(request_data),
+        )
+        self.assertEqual(resp.status_code, 200)
+        results = resp.get_json()["strings"]
         for k, v in results.items():
-            self.assertEqual(self.util.pseudolocalize(data[k]), v)
+            self.assertEqual(fresh_util_for_api_test.pseudolocalize(data[k]), v)
+
+    def test_po_file_upload_success(self):
+        po_content = 'msgid "Hello"\nmsgstr ""'
+        # Apply the specific transforms to "Hello" to get the expected output part
+        # The self.util is already configured with these transforms in setUp
+        expected_output_part = self.util.pseudolocalize("Hello")
+
+        data = {
+            'po_file': (io.BytesIO(po_content.encode('utf-8')), 'test.po')
+        }
+        resp = self.client.post(
+            ui_base_url + "po_upload",
+            content_type='multipart/form-data',
+            data=data
+        )
+        self.assertEqual(resp.status_code, 200)
+        self.assertIn('attachment', resp.headers['Content-Disposition'])
+        self.assertIn('filename=pseudolocalized.po', resp.headers['Content-Disposition'])
+        # Check if the pseudolocalized string is in the output
+        # The actual PO file will have more structure (headers, etc.)
+        # but checking for the transformed msgid is a good indicator.
+        self.assertIn(expected_output_part, resp.data.decode('utf-8'))
+
+
+    def test_po_file_upload_no_file(self):
+        resp = self.client.post(
+            ui_base_url + "po_upload",
+            content_type='multipart/form-data',
+            data={}
+        )
+        self.assertEqual(resp.status_code, 400)
+        json_data = resp.get_json()
+        self.assertIn("error", json_data)
+        self.assertIn("No file part", json_data["error"])
+
+    def test_po_file_upload_wrong_file_type(self):
+        data = {
+            'po_file': (io.BytesIO(b"this is not a po file"), 'test.txt')
+        }
+        resp = self.client.post(
+            ui_base_url + "po_upload",
+            content_type='multipart/form-data',
+            data=data
+        )
+        self.assertEqual(resp.status_code, 400)
+        json_data = resp.get_json()
+        self.assertIn("error", json_data)
+        self.assertIn("Invalid file type", json_data["error"])
+
+    def test_po_file_upload_empty_filename(self):
+        data = {
+            'po_file': (io.BytesIO(b"some content"), '') # Empty filename
+        }
+        resp = self.client.post(
+            ui_base_url + "po_upload",
+            content_type='multipart/form-data',
+            data=data
+        )
+        self.assertEqual(resp.status_code, 400)
+        json_data = resp.get_json()
+        self.assertIn("error", json_data)
+        self.assertIn("No file selected", json_data["error"])
 
 
 if __name__ == "__main__":