diff --git a/app/__init__.py b/app/__init__.py
index afa61bcb..23186789 100644
--- a/app/__init__.py
+++ b/app/__init__.py
@@ -114,3 +114,7 @@ from .utils import clearNotifications
 def check_for_notifications():
 	if current_user.is_authenticated:
 		clearNotifications(request.path)
+
+@app.errorhandler(404)
+def page_not_found(e):
+	return render_template("404.html"), 404
diff --git a/app/blueprints/api/endpoints.py b/app/blueprints/api/endpoints.py
index adca61a4..4beec0af 100644
--- a/app/blueprints/api/endpoints.py
+++ b/app/blueprints/api/endpoints.py
@@ -14,7 +14,7 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
-from flask import request, jsonify, current_app, abort
+from flask import request, jsonify, current_app
 from flask_login import current_user, login_required
 from sqlalchemy.sql.expression import func
 
@@ -115,11 +115,11 @@ def topic_set_discard():
 	tid = request.args.get("tid")
 	discard = request.args.get("discard")
 	if tid is None or discard is None:
-		abort(400)
+		error(400, "Missing topic ID or discard bool")
 
 	topic = ForumTopic.query.get(tid)
 	if not topic.checkPerm(current_user, Permission.TOPIC_DISCARD):
-		abort(403)
+		error(403, "Permission denied, need: TOPIC_DISCARD")
 
 	topic.discarded = discard == "true"
 	db.session.commit()
@@ -151,13 +151,13 @@ def list_all_releases():
 	if "author" in request.args:
 		author = User.query.filter_by(username=request.args["author"]).first()
 		if author is None:
-			abort(404)
+			error(404, "Author not found")
 		query = query.filter(PackageRelease.package.has(author=author))
 
 	if "maintainer" in request.args:
 		maintainer = User.query.filter_by(username=request.args["maintainer"]).first()
 		if maintainer is None:
-			abort(404)
+			error(404, "Maintainer not found")
 		query = query.join(Package)
 		query = query.filter(Package.maintainers.any(id=maintainer.id))
 
diff --git a/app/flatpages/help/api.md b/app/flatpages/help/api.md
index ef9503ea..6e5693cc 100644
--- a/app/flatpages/help/api.md
+++ b/app/flatpages/help/api.md
@@ -122,8 +122,8 @@ Supported query parameters:
         * `min_minetest_version`: dict or null, minimum supported minetest version (inclusive).
         * `max_minetest_version`: dict or null, minimum supported minetest version (inclusive).
         * `package`
-            * `author`: author username.
-            * `name`
+            * `author`: author username
+            * `name`: technical name
             * `type`: `mod`, `game`, or `txp`
 * GET `/api/packages/<username>/<name>/releases/` (List)
     * Returns array of release dictionaries, see above, but without package info.
diff --git a/app/templates/404.html b/app/templates/404.html
new file mode 100644
index 00000000..5d44ec1b
--- /dev/null
+++ b/app/templates/404.html
@@ -0,0 +1,13 @@
+{% extends "base.html" %}
+
+{% block title %}
+	Page not found
+{% endblock %}
+
+{% block content %}
+	<h1>Page not found</h1>
+	<p>
+		That page could not be found. The link may be broken, the page may have been deleted,
+		or you may not have access to it.
+	</p>
+{% endblock %}