diff --git a/WebHostLib/__init__.py b/WebHostLib/__init__.py
index 5daa2f1e..7c9aacca 100644
--- a/WebHostLib/__init__.py
+++ b/WebHostLib/__init__.py
@@ -15,11 +15,6 @@ UPLOAD_FOLDER = os.path.relpath('uploads')
 LOGS_FOLDER = os.path.relpath('logs')
 os.makedirs(LOGS_FOLDER, exist_ok=True)
 
-
-def allowed_file(filename):
-    return filename.endswith(('multidata', ".zip"))
-
-
 app = Flask(__name__)
 Pony(app)
 
@@ -35,8 +30,11 @@ app.config['MAX_CONTENT_LENGTH'] = 4 * 1024 * 1024  # 4 megabyte limit
 # if you want persistent sessions on your server, make sure you make this a constant in your config.yaml
 app.config["SECRET_KEY"] = os.urandom(32)
 app.config['SESSION_PERMANENT'] = True
-app.config[
-    "WAITRESS_THREADS"] = 10  # waitress uses one thread for I/O, these are for processing of views that then get sent
+
+# waitress uses one thread for I/O, these are for processing of views that then get sent
+# berserkermulti.world uses gunicorn + nginx; ignoring this option
+app.config["WAITRESS_THREADS"] = 10
+#a default that just works. berserkermulti.world runs on mariadb
 app.config["PONY"] = {
     'provider': 'sqlite',
     'filename': os.path.abspath('db.db3'),
@@ -111,4 +109,4 @@ def host_room(room: UUID):
 
 
 from WebHostLib.customserver import run_server_process
-from . import tracker, upload, landing  # to trigger app routing picking up on it
+from . import tracker, upload, landing, check  # to trigger app routing picking up on it
diff --git a/WebHostLib/check.py b/WebHostLib/check.py
new file mode 100644
index 00000000..557cbc97
--- /dev/null
+++ b/WebHostLib/check.py
@@ -0,0 +1,66 @@
+import zipfile
+
+
+from flask import request, flash, redirect, url_for, session, render_template
+
+from WebHostLib import app
+
+banned_zip_contents = (".sfc",)
+
+
+def allowed_file(filename):
+    return filename.endswith(('.txt', ".yaml", ".zip"))
+
+from Mystery import roll_settings
+from Utils import parse_yaml
+
+@app.route('/mysterycheck', methods=['GET', 'POST'])
+def mysterycheck():
+    if request.method == 'POST':
+        # check if the post request has the file part
+        if 'file' not in request.files:
+            flash('No file part')
+        else:
+            options = {}
+            file = request.files['file']
+            # if user does not select file, browser also
+            # submit an empty part without filename
+            if file.filename == '':
+                flash('No selected file')
+            elif file and allowed_file(file.filename):
+                if file.filename.endswith(".zip"):
+
+                    with zipfile.ZipFile(file, 'r') as zfile:
+                        infolist = zfile.infolist()
+
+                        for file in infolist:
+                            if file.filename.endswith(banned_zip_contents):
+                                return "Uploaded data contained a rom file, which is likely to contain copyrighted material. Your file was deleted."
+                            elif file.filename.endswith(".yaml"):
+                                options[file.filename] = zfile.open(file, "r").read()
+                            elif file.filename.endswith(".txt"):
+                                options[file.filename] = zfile.open(file, "r").read()
+                else:
+                    options = {file.filename: file.read()}
+                if not options:
+                    flash("Did not find a .yaml file to process.")
+                else:
+                    results = {}
+                    for filename, text in options.items():
+                        try:
+                            yaml_data = parse_yaml(text)
+                        except Exception as e:
+                            results[filename] = f"Failed to parse YAML data in {filename}: {e}"
+                        else:
+                            try:
+                                roll_settings(yaml_data)
+                            except Exception as e:
+                                results[filename] = f"Failed to generate mystery in {filename}: {e}"
+                            else:
+                                results[filename] = "Looks fine"
+                    return render_template("checkresult.html", results=results)
+
+            else:
+                flash("Not recognized file format. Awaiting a .yaml file.")
+
+    return render_template("check.html")
diff --git a/WebHostLib/templates/check.html b/WebHostLib/templates/check.html
new file mode 100644
index 00000000..923db891
--- /dev/null
+++ b/WebHostLib/templates/check.html
@@ -0,0 +1,23 @@
+{% extends 'layout.html' %}
+
+{% block head %}
+    {{ super() }}
+    <title>Mystery Check Result</title>
+    <link rel="stylesheet" type="text/css" href="{{ static_autoversion("uploads.css") }}" />
+    <script type="application/ecmascript" src="{{ static_autoversion("uploads.js") }}"></script>
+{% endblock %}
+
+{% block body %}
+    <div id="uploads-wrapper">
+        <div id="uploads" class="main-content">
+            <h3>Upload Yaml</h3>
+            <p>This page checks a .yaml file for you, to be used as options for a mystery multiworld. You can also upload a .zip with multiple YAMLs.</p>
+            <div id="uploads-form-wrapper">
+                <form id="upload-form" method="post" enctype="multipart/form-data">
+                    <input id="file-input" type="file" name="file">
+                </form>
+                <button id="upload-button">Upload</button>
+            </div>
+        </div>
+    </div>
+{% endblock %}
diff --git a/WebHostLib/templates/checkresult.html b/WebHostLib/templates/checkresult.html
new file mode 100644
index 00000000..8411696e
--- /dev/null
+++ b/WebHostLib/templates/checkresult.html
@@ -0,0 +1,12 @@
+{% extends 'layout.html' %}
+
+{% block head %}
+    {{ super() }}
+    <title>Upload Mystery YAML</title>
+{% endblock %}
+
+{% block body %}
+    {%   for filename, resulttext in results.items() %}
+    <span>{{ filename }}: {{ resulttext }}</span><br>
+    {% endfor %}
+{% endblock %}
diff --git a/WebHostLib/upload.py b/WebHostLib/upload.py
index 547665d7..91e4cc19 100644
--- a/WebHostLib/upload.py
+++ b/WebHostLib/upload.py
@@ -6,7 +6,7 @@ import logging
 from flask import request, flash, redirect, url_for, session, render_template
 from pony.orm import commit, select
 
-from WebHostLib import app, allowed_file, Seed, Room, Patch
+from WebHostLib import app, Seed, Room, Patch
 
 accepted_zip_contents = {"patches": ".bmbp",
                          "spoiler": ".txt",
@@ -71,3 +71,7 @@ def uploads():
                 flash("Not recognized file format. Awaiting a .multidata file.")
     rooms = select(room for room in Room if room.owner == session["_id"])
     return render_template("uploads.html", rooms=rooms)
+
+
+def allowed_file(filename):
+    return filename.endswith(('multidata', ".zip"))
\ No newline at end of file