diff --git a/_data/current.yml b/_data/current.yml
index 744b4d20..11c06d79 100644
--- a/_data/current.yml
+++ b/_data/current.yml
@@ -203,6 +203,13 @@
   url: https://testdag.nl/?utm_source=testingconferences
   status: CFP is Closed
 
+- name: "QX Day (Sogeti) 2026"
+  location: Utrecht, Netherlands
+  dates: "October 2026 (TBA)"
+  url: https://www.sogeti.nl/events/qx-day-2026/?utm_source=testingconferences
+  status: Announced
+
+
 - name: TestGuild IRL Austin 2026
   location: Austin, TX, USA
   dates: "November 3, 2026"
diff --git a/_data/past.yml b/_data/past.yml
index f063547b..882d524d 100644
--- a/_data/past.yml
+++ b/_data/past.yml
@@ -73,12 +73,28 @@
   dates: "June 2-3, 2026"
   url: https://live2test.com/?utm_source=testingconferences
 
+- name: Ministry of Testing NL Chapter Meetup
+  location: Veenendaal, Netherlands
+  dates: "May 28, 2026"
+  url: https://www.ministryoftesting.com/chapters/mot-netherlands/events/mot-netherlands-280526
+
 - name: "expo:QA 26"
   location: Madrid, Spain
   dates: "May 26-28, 2026"
   url: https://expoqa.eu/?utm_source=testingconferences
   twitter: expoqa
 
+- name: "The Best in Test 2026 (Sopra Steria)"
+  location: Nieuwegein, Netherlands
+  dates: "May 13, 2026"
+  url: https://careers.soprasteria.nl/the-best-in-test
+
+- name: Testnet Voorjaarsevenement 2026
+  location: Nieuwegein, Netherlands
+  dates: "May 6, 2026"
+  url: https://www.testnet.org/evenement/entry/29924/?evenement=voorjaarsevenement-2026
+
+
 - name: Istanbul Software Testing Conference
   location: Istanbul, Turkey
   dates: "May 21-22, 2026"
diff --git a/tools/validate_data.py b/tools/validate_data.py
new file mode 100644
index 00000000..aefc569e
--- /dev/null
+++ b/tools/validate_data.py
@@ -0,0 +1,214 @@
+#!/usr/bin/env python3
+import sys
+import os
+import re
+from datetime import datetime
+from urllib.parse import urlparse, parse_qs
+
+ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+
+DATA_FILES = {
+    '_data/current.yml': {
+        'allowed': {'name', 'location', 'dates', 'url', 'twitter', 'status'},
+        'required': {'name', 'location', 'dates', 'url'},
+        'order': 'ascending',
+        'strict': True,
+        'check_tracking': True
+    },
+    '_data/past.yml': {
+        'allowed': {'name', 'location', 'dates', 'url', 'twitter', 'status', 'video_playlist', 'video_url'},
+        'required': {'name', 'location', 'dates', 'url'},
+        'order': None,
+        'strict': False,
+        'check_tracking': False
+    },
+    '_data/closed.yml': {
+        'allowed': {'name', 'location', 'first_date', 'last_date', 'url', 'twitter', 'status'},
+        'required': {'name', 'location', 'first_date', 'last_date', 'url'},
+        'order': None,
+        'strict': True,
+        'check_tracking': True
+    }
+}
+
+MONTH_MAP = {
+    'jan': 1, 'january': 1,
+    'feb': 2, 'february': 2,
+    'mar': 3, 'march': 3,
+    'apr': 4, 'april': 4,
+    'may': 5,
+    'jun': 6, 'june': 6,
+    'jul': 7, 'july': 7,
+    'aug': 8, 'august': 8,
+    'sep': 9, 'sept': 9, 'september': 9,
+    'oct': 10, 'october': 10,
+    'nov': 11, 'november': 11,
+    'dec': 12, 'december': 12
+}
+
+MONTH_PATTERN = r'(?:January|February|March|April|May|June|July|August|September|October|November|December|Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Sept|Oct|Nov|Dec)'
+
+def parse_simple_yaml_list(filepath):
+    entries = []
+    curr = None
+    with open(filepath, 'r', encoding='utf-8') as f:
+        lines = f.readlines()
+    for line in lines:
+        raw = line
+        stripped = line.strip()
+        if not stripped or stripped.startswith('#'):
+            continue
+        if stripped.startswith('- '):
+            if curr is not None:
+                entries.append(curr)
+            curr = {}
+            body = stripped[2:].strip()
+            if ':' in body:
+                k, v = body.split(':', 1)
+                curr[k.strip()] = v.strip().strip('\"\'')
+        elif curr is not None and ':' in stripped:
+            k, v = stripped.split(':', 1)
+            curr[k.strip()] = v.strip().strip('\"\'')
+    if curr is not None:
+        entries.append(curr)
+    return entries
+
+def parse_event_date(value, boundary='start'):
+    if not value:
+        return None
+    text = str(value).strip().replace('–', '-').replace('—', '-')
+    
+    m = re.match(r'^(' + MONTH_PATTERN + r')\s+(\d{1,2})\s*-\s*(' + MONTH_PATTERN + r')\s*(\d{1,2}),?\s*(\d{4})$', text, re.IGNORECASE)
+    if m:
+        s_m, s_d, e_m, e_d, year = m.group(1), m.group(2), m.group(3), m.group(4), m.group(5)
+    else:
+        m = re.match(r'^(' + MONTH_PATTERN + r')\s+(\d{1,2})\s*-\s*(\d{1,2}),?\s*(\d{4})$', text, re.IGNORECASE)
+        if m:
+            s_m = e_m = m.group(1)
+            s_d, e_d, year = m.group(2), m.group(3), m.group(4)
+        else:
+            m = re.match(r'^(' + MONTH_PATTERN + r')\s+(\d{1,2}),?\s*(\d{4})$', text, re.IGNORECASE)
+            if m:
+                s_m = e_m = m.group(1)
+                s_d = e_d = m.group(2)
+                year = m.group(3)
+            else:
+                return None
+
+    month_name = e_m if boundary == 'end' else s_m
+    day = e_d if boundary == 'end' else s_d
+    m_idx = MONTH_MAP.get(month_name.lower())
+    if not m_idx:
+        return None
+    try:
+        return datetime(int(year), m_idx, int(day))
+    except ValueError:
+        return None
+
+def valid_url(url_str):
+    try:
+        u = urlparse(url_str)
+        return u.scheme in ('http', 'https') and bool(u.netloc)
+    except Exception:
+        return False
+
+def has_tracking_source(url_str):
+    try:
+        u = urlparse(url_str)
+        qs = parse_qs(u.query)
+        return 'testingconferences' in qs.get('utm_source', [])
+    except Exception:
+        return False
+
+def main():
+    errors = []
+    warnings = []
+    seen_names = {}
+
+    for rel_path, rules in DATA_FILES.items():
+        abs_path = os.path.join(ROOT, rel_path)
+        if not os.path.exists(abs_path):
+            errors.append(f"{rel_path}: file not found")
+            continue
+        
+        data = parse_simple_yaml_list(abs_path)
+        local_names = set()
+        previous_date = None
+
+        for index, event in enumerate(data, 1):
+            label = f"{rel_path}[{index}]"
+            name = event.get('name', '').strip()
+            display = f"{rel_path}: {name}" if name else label
+
+            unknown_fields = set(event.keys()) - rules['allowed']
+            if unknown_fields:
+                msg = f"{display}: unknown fields: {', '.join(sorted(unknown_fields))}"
+                if rules['strict']:
+                    errors.append(msg)
+                else:
+                    warnings.append(msg)
+
+            for req in rules['required']:
+                if not event.get(req):
+                    msg = f"{display}: missing required field `{req}`"
+                    if rules['strict']:
+                        errors.append(msg)
+                    else:
+                        warnings.append(msg)
+
+            if name:
+                if name in local_names:
+                    warnings.append(f"{display}: duplicate name in {rel_path}")
+                local_names.add(name)
+                seen_names.setdefault(name, []).append(rel_path)
+
+            if '@' in event.get('twitter', ''):
+                errors.append(f"{display}: twitter value should not include @")
+
+            if 'url' in event:
+                u = event['url']
+                if not valid_url(u):
+                    errors.append(f"{display}: url is not a valid HTTP(S) URL")
+                elif rules['check_tracking'] and not has_tracking_source(u):
+                    warnings.append(f"{display}: url is missing utm_source=testingconferences")
+
+            if 'video_playlist' in event and not valid_url(event['video_playlist']):
+                errors.append(f"{display}: video_playlist is not a valid HTTP(S) URL")
+
+            if 'video_url' in event and not valid_url(event['video_url']):
+                warnings.append(f"{display}: video_url is not a valid HTTP(S) URL")
+
+            if rel_path == '_data/closed.yml':
+                f_date = parse_event_date(event.get('first_date'), 'start')
+                l_date = parse_event_date(event.get('last_date'), 'end')
+                if event.get('first_date') and not f_date:
+                    warnings.append(f"{display}: could not parse first_date")
+                if event.get('last_date') and not l_date:
+                    warnings.append(f"{display}: could not parse last_date")
+                if f_date and l_date and f_date > l_date:
+                    errors.append(f"{display}: first_date is after last_date")
+            elif event.get('dates'):
+                order_date = parse_event_date(event.get('dates'), 'start')
+                if not order_date and 'TBA' not in event.get('dates', '') and not re.search(r'20\d\d', event.get('dates','')):
+                    warnings.append(f"{display}: could not parse dates for ordering")
+
+                if rules['order'] and order_date and previous_date:
+                    if rules['order'] == 'ascending' and order_date < previous_date:
+                        warnings.append(f"{display}: appears out of chronological order ({order_date.strftime('%Y-%m-%d')} < {previous_date.strftime('%Y-%m-%d')})")
+                if order_date:
+                    previous_date = order_date
+
+    for w in warnings:
+        print(f"WARNING: {w}", file=sys.stderr)
+    for e in errors:
+        print(f"ERROR: {e}", file=sys.stderr)
+
+    if not errors:
+        print(f"Conference data validation passed with {len(warnings)} warning(s).")
+        sys.exit(0)
+    else:
+        print(f"Conference data validation failed with {len(errors)} error(s) and {len(warnings)} warning(s).", file=sys.stderr)
+        sys.exit(1)
+
+if __name__ == '__main__':
+    main()