diff --git a/onionr/communicator2.py b/onionr/communicator2.py
index 1aabc9fc..98d1aecd 100755
--- a/onionr/communicator2.py
+++ b/onionr/communicator2.py
@@ -134,15 +134,18 @@ class OnionrCommunicatorDaemon:
                 content = base64.b64decode(content)
                 if self._core._crypto.sha3Hash(content) == blockHash:
                     content = content.decode() # decode here because sha3Hash needs bytes above
-                    metas = self._core._utils.getBlockMetadataFromData(content)
+                    metas = self._core._utils.getBlockMetadataFromData(content) # returns tuple(metadata, meta), meta is also in metadata
                     metadata = metas[0]
                     meta = metas[1]
-                    if self._core._crypto.verifyPow(metas[2], metadata) and self._core._utils.validateMetadata(metadata):
-                        logger.info('Block passed proof, saving.')
-                        self._core.setData(content)
-                        self._core.addToBlockDB(blockHash, dataSaved=True)
+                    if self._core._utils.validateMetadata(metadata):
+                        if self._core._crypto.verifyPow(metas[2], metadata):
+                            logger.info('Block passed proof, saving.')
+                            self._core.setData(content)
+                            self._core.addToBlockDB(blockHash, dataSaved=True)
+                        else:
+                            logger.warn('POW failed for block ' + blockHash)
                     else:
-                        logger.warn('POW failed for block ' + blockHash)
+                        logger.warn('Metadata for ' + blockHash + ' is invalid.')
                     self.blockQueue.remove(blockHash)
                 else:
                     logger.warn('Block hash validation failed for ' + blockHash + ' got ' + self._core._crypto.sha3Hash(content))
diff --git a/onionr/onionrutils.py b/onionr/onionrutils.py
index 77323633..84225b04 100644
--- a/onionr/onionrutils.py
+++ b/onionr/onionrutils.py
@@ -18,7 +18,7 @@
     along with this program.  If not, see <https://www.gnu.org/licenses/>.
 '''
 # Misc functions that do not fit in the main api, but are useful
-import getpass, sys, requests, os, socket, hashlib, logger, sqlite3, config, binascii, time, base64, json, glob, shutil, math
+import getpass, sys, requests, os, socket, hashlib, logger, sqlite3, config, binascii, time, base64, json, glob, shutil, math, json
 import nacl.signing, nacl.encoding
 from onionrblockapi import Block
 import onionrexceptions
@@ -313,7 +313,34 @@ class OnionrUtils:
     def validateMetadata(metadata):
         '''Validate metadata meets onionr spec (does not validate proof value computation), take in either dictionary or json string'''
         # TODO, make this check sane sizes
-        return True
+        retData = False
+        
+        # convert to dict if it is json string
+        if type(metadata) is str:
+            try:
+                metadata = json.loads(metadata)
+            except json.JSONDecodeError:
+                pass
+
+        # Validate metadata dict for invalid keys to sizes that are too large
+        if type(metadata) is dict:
+            for i in metadata:
+                try:
+                    self._core.requirements.blockMetadataLengths[i]
+                except KeyError:
+                    logger.warn('Block has invalid metadata key ' + i)
+                    break
+                else:
+                    if self._core.requirements.blockMetadataLengths[i] < len(metadata[i]):
+                        logger.warn('Block metadata key ' + i + ' exceeded maximum size')
+                        break
+            else:
+                # if metadata loop gets no errors, it does not break, therefore metadata is valid
+                retData = True
+        else:
+            logger.warn('In call to utils.validateMetadata, metadata must be JSON string or a dictionary object')
+
+        return retData
 
     def validatePubKey(self, key):
         '''