diff --git a/defs/coins/combine.py b/defs/coins/combine.py
new file mode 100755
index 000000000..d883bbb55
--- /dev/null
+++ b/defs/coins/combine.py
@@ -0,0 +1,80 @@
+#!/usr/bin/env python3
+
+import json
+import glob
+import re
+
+
+def check_type(val, types, nullable=False, empty=False, regex=None):
+    # check nullable
+    if nullable and val is None:
+        return True
+    # check empty
+    try:
+        if not empty and len(val) == 0:
+            return False
+    except TypeError:
+        pass
+    # check regex
+    if regex is not None:
+        if types is not str:
+            return False
+        m = re.match(regex, val)
+        if not m or m.string != val:
+            return False
+    # check type
+    if isinstance(types, list):
+        return True in [isinstance(val, t) for t in types]
+    else:
+        return isinstance(val, types)
+
+
+def validate_coin(coin):
+    assert check_type(coin['coin_name'], str)
+    assert check_type(coin['coin_shortcut'], str)
+    assert check_type(coin['coin_label'], str)
+    assert check_type(coin['website'], str, empty=True)
+    assert check_type(coin['github'], str, empty=True)
+    assert check_type(coin['maintainer'], str)
+    assert check_type(coin['curve_name'], str)
+    assert check_type(coin['address_type'], int)
+    assert check_type(coin['address_type_p2sh'], int)
+    assert coin['address_type'] != coin['address_type_p2sh']
+    assert check_type(coin['maxfee_kb'], int)
+    assert check_type(coin['minfee_kb'], int)
+    assert coin['maxfee_kb'] > coin['minfee_kb']
+    assert check_type(coin['hash_genesis_block'], str, regex=r'[0-9a-f]{64}')
+    assert check_type(coin['xprv_magic'], str, regex=r'[0-9a-f]{8}')
+    assert check_type(coin['xpub_magic'], str, regex=r'[0-9a-f]{8}')
+    assert check_type(coin['xpub_magic_segwit_p2sh'], str, regex=r'[0-9a-f]{8}', nullable=True)
+    assert check_type(coin['slip44'], int)
+    assert check_type(coin['segwit'], bool)
+    assert check_type(coin['decred'], bool)
+    assert check_type(coin['forkid'], int, nullable=True)
+    assert check_type(coin['force_bip143'], bool, nullable=True)
+    assert check_type(coin['default_fee_b'], dict)
+    assert check_type(coin['dust_limit'], int)
+    assert check_type(coin['blocktime_minutes'], [int, float])
+    assert check_type(coin['signed_message_header'], str)
+    assert check_type(coin['min_address_length'], int)
+    assert check_type(coin['max_address_length'], int)
+    assert check_type(coin['bitcore'], list, empty=True)
+    assert check_type(coin['bech32_prefix'], str, nullable=True)
+    assert check_type(coin['cashaddr_prefix'], str, nullable=True)
+
+
+def process_json(fn):
+    j = json.load(open(fn))
+    validate_coin(j)
+    return j
+
+
+coins = {}
+for fn in glob.glob('*.json'):
+    c = process_json(fn)
+    n = c['coin_name']
+    coins[n] = c
+
+json.dump(coins, open('../coins.json', 'w'), indent=4, sort_keys=True)
+
+print('OK')