diff --git a/boker/app.py b/boker/app.py
index 3247e99..3465e12 100644
--- a/boker/app.py
+++ b/boker/app.py
@@ -3,7 +3,10 @@ from __future__ import annotations
 
 import click
 import os
-from flask import Flask, render_template
+from uuid import uuid4
+
+from flask import Flask, render_template, request
+from werkzeug.exceptions import HTTPException
 
 from boker.auth import current_user_id, is_logged_in, is_site_admin, normalize_email
 from boker.config import DEFAULT_SECRET_KEY, Config, ProductionConfig
@@ -64,6 +67,20 @@ def create_app(config_overrides: dict | None = None) -> Flask:
     def forbidden(e):
         return render_template("403.html"), 403
 
+    @app.errorhandler(Exception)
+    def unexpected_error(error):
+        if isinstance(error, HTTPException):
+            return error
+
+        crash_id = uuid4().hex[:12]
+        app.logger.exception(
+            "Unhandled exception [%s] during %s %s",
+            crash_id,
+            request.method,
+            request.path,
+        )
+        return render_template("500.html", crash_id=crash_id), 500
+
     @app.cli.command("init-db")
     def init_db_command() -> None:
         if not database_extensions_available() or db is None:
diff --git a/static/css/style.css b/static/css/style.css
index 2aa6683..09da5f2 100644
--- a/static/css/style.css
+++ b/static/css/style.css
@@ -5925,6 +5925,9 @@ select.control { cursor: pointer; }
 .error-pg--403 .error-pg__suit {
   color: rgba(155,140,240,.06);
 }
+.error-pg--500 .error-pg__suit {
+  color: rgba(224,177,92,.07);
+}
 
 .error-pg__body {
   position: relative;
@@ -5971,6 +5974,18 @@ select.control { cursor: pointer; }
   justify-content: center;
 }
 
+.error-pg__trace {
+  margin: -12px 0 28px;
+  padding: 6px 10px;
+  border: 1px solid var(--line);
+  border-radius: 6px;
+  color: var(--faint);
+  background: var(--panel);
+  font-family: var(--font-mono);
+  font-size: 12px;
+  line-height: 1.4;
+}
+
 /* ================================================================
    LANDING — hero kicker (replaces pill eyebrow in hero only)
    ================================================================ */
diff --git a/templates/500.html b/templates/500.html
new file mode 100644
index 0000000..24ece0f
--- /dev/null
+++ b/templates/500.html
@@ -0,0 +1,20 @@
+{% extends "base.html" %}
+{% block title %}500 · Something Went Wrong · myboker.org{% endblock %}
+{% block page_class %}page--error{% endblock %}
+{% block content %}
+
+<div class="error-pg error-pg--500">
+    <div class="error-pg__suit" aria-hidden="true">♦</div>
+    <div class="error-pg__body">
+        <span class="error-pg__code">500</span>
+        <h1 class="error-pg__title">Something went wrong.</h1>
+        <p class="error-pg__sub">The app hit an unexpected error. Try again in a minute, or contact support if it keeps happening.</p>
+        <p class="error-pg__trace">Incident {{ crash_id }}</p>
+        <div class="error-pg__actions">
+            <a class="btn btn--primary btn--lg" href="{{ url_for('public.home') }}">Go home →</a>
+            <a class="btn btn--ghost btn--lg" href="{{ url_for('public.help') }}#contact">Contact support</a>
+        </div>
+    </div>
+</div>
+
+{% endblock %}
diff --git a/tests/test_errors.py b/tests/test_errors.py
new file mode 100644
index 0000000..ea0d844
--- /dev/null
+++ b/tests/test_errors.py
@@ -0,0 +1,47 @@
+import re
+import tempfile
+import unittest
+from pathlib import Path
+
+from app import create_app
+from boker.db import db
+
+
+class ErrorPageTests(unittest.TestCase):
+    def setUp(self):
+        self.tmpdir = tempfile.TemporaryDirectory()
+        db_path = Path(self.tmpdir.name) / "test.sqlite3"
+        self.app = create_app(
+            {
+                "TESTING": True,
+                "PROPAGATE_EXCEPTIONS": False,
+                "SQLALCHEMY_DATABASE_URI": f"sqlite:///{db_path}",
+                "WTF_CSRF_ENABLED": False,
+            }
+        )
+
+        @self.app.get("/explode")
+        def explode():
+            raise RuntimeError("boom")
+
+        self.client = self.app.test_client()
+
+    def tearDown(self):
+        with self.app.app_context():
+            db.session.remove()
+            db.drop_all()
+            db.engine.dispose()
+        self.tmpdir.cleanup()
+
+    def test_unexpected_errors_render_crash_page_with_incident_id(self):
+        response = self.client.get("/explode")
+
+        self.assertEqual(response.status_code, 500)
+        self.assertIn(b"Something went wrong.", response.data)
+        self.assertIn(b"Incident", response.data)
+        self.assertNotIn(b"RuntimeError", response.data)
+        self.assertRegex(response.get_data(as_text=True), re.compile(r"Incident [a-f0-9]{12}"))
+
+
+if __name__ == "__main__":
+    unittest.main()