diff --git a/hub/db/db.py b/hub/db/db.py
index 6811dba..f14fe93 100644
--- a/hub/db/db.py
+++ b/hub/db/db.py
@@ -40,7 +40,7 @@ class SecondaryDB:
                  cache_all_claim_txos: bool = False, cache_all_tx_hashes: bool = False,
                  blocking_channel_ids: List[str] = None,
                  filtering_channel_ids: List[str] = None, executor: ThreadPoolExecutor = None,
-                 index_address_status=False, merkle_cache_size=32768):
+                 index_address_status=False, merkle_cache_size=32768, tx_cache_size=32768):
         self.logger = logging.getLogger(__name__)
         self.coin = coin
         self._executor = executor
@@ -90,7 +90,7 @@ class SecondaryDB:
         self.header_mc = MerkleCache(self.merkle, self.fs_block_hashes)
 
         # lru cache of tx_hash: (tx_bytes, tx_num, position, tx_height)
-        self.tx_cache = LRUCacheWithMetrics(2 ** 15, metric_name='tx', namespace=NAMESPACE)
+        self.tx_cache = LRUCacheWithMetrics(tx_cache_size, metric_name='tx', namespace=NAMESPACE)
         # lru cache of block heights to merkle trees of the block tx hashes
         self.merkle_cache = LRUCacheWithMetrics(merkle_cache_size, metric_name='merkle', namespace=NAMESPACE)
 
diff --git a/hub/herald/db.py b/hub/herald/db.py
index 23692c1..fa0153a 100644
--- a/hub/herald/db.py
+++ b/hub/herald/db.py
@@ -9,10 +9,10 @@ class HeraldDB(SecondaryDB):
                  cache_all_claim_txos: bool = False, cache_all_tx_hashes: bool = False,
                  blocking_channel_ids: List[str] = None,
                  filtering_channel_ids: List[str] = None, executor: ThreadPoolExecutor = None,
-                 index_address_status=False, merkle_cache_size=32768):
+                 index_address_status=False, merkle_cache_size=32768, tx_cache_size=32768):
         super().__init__(coin, db_dir, secondary_name, max_open_files, reorg_limit, cache_all_claim_txos,
                          cache_all_tx_hashes, blocking_channel_ids, filtering_channel_ids, executor,
-                         index_address_status, merkle_cache_size)
+                         index_address_status, merkle_cache_size, tx_cache_size)
         # self.headers = None
 
     # async def _read_headers(self):
diff --git a/hub/herald/env.py b/hub/herald/env.py
index e6b57fb..5a78f7f 100644
--- a/hub/herald/env.py
+++ b/hub/herald/env.py
@@ -12,7 +12,7 @@ class ServerEnv(Env):
                  database_query_timeout=None, elastic_notifier_host=None, elastic_notifier_port=None,
                  blocking_channel_ids=None, filtering_channel_ids=None, peer_hubs=None, peer_announce=None,
                  index_address_status=None, address_history_cache_size=None, daemon_ca_path=None,
-                 merkle_cache_size=None, resolved_url_cache_size=None):
+                 merkle_cache_size=None, resolved_url_cache_size=None, tx_cache_size=None):
         super().__init__(db_dir, max_query_workers, chain, reorg_limit, prometheus_port, cache_all_tx_hashes,
                          cache_all_claim_txos, blocking_channel_ids, filtering_channel_ids, index_address_status)
         self.daemon_url = daemon_url if daemon_url is not None else self.required('DAEMON_URL')
@@ -57,6 +57,8 @@ class ServerEnv(Env):
         self.merkle_cache_size = merkle_cache_size if merkle_cache_size is not None else self.integer('MERKLE_CACHE_SIZE', 32768)
         self.resolved_url_cache_size = resolved_url_cache_size if resolved_url_cache_size is not None else self.integer(
             'RESOLVED_URL_CACHE_SIZE', 32768)
+        self.tx_cache_size = tx_cache_size if tx_cache_size is not None else self.integer(
+            'TX_CACHE_SIZE', 32768)
 
     @classmethod
     def contribute_to_arg_parser(cls, parser):
@@ -117,7 +119,10 @@ class ServerEnv(Env):
                             default=cls.integer('RESOLVED_URL_CACHE_SIZE', 32768),
                             help="Size of the lru cache of resolved urls. "
                                  "Can be set in the env with 'RESOLVED_URL_CACHE_SIZE'")
-
+        parser.add_argument('--tx_cache_size', type=int,
+                            default=cls.integer('TX_CACHE_SIZE', 32768),
+                            help="Size of the lru cache of transactions. "
+                                 "Can be set in the env with 'TX_CACHE_SIZE'")
     @classmethod
     def from_arg_parser(cls, args):
         return cls(
@@ -134,5 +139,6 @@ class ServerEnv(Env):
             filtering_channel_ids=args.filtering_channel_ids, elastic_notifier_host=args.elastic_notifier_host,
             elastic_notifier_port=args.elastic_notifier_port, index_address_status=args.index_address_statuses,
             address_history_cache_size=args.address_history_cache_size, daemon_ca_path=args.daemon_ca_path,
-            merkle_cache_size=args.merkle_cache_size, resolved_url_cache_size=args.resolved_url_cache_size
+            merkle_cache_size=args.merkle_cache_size, resolved_url_cache_size=args.resolved_url_cache_size,
+            tx_cache_size=args.tx_cache_size
         )
diff --git a/hub/herald/service.py b/hub/herald/service.py
index a792706..3a2a71c 100644
--- a/hub/herald/service.py
+++ b/hub/herald/service.py
@@ -42,7 +42,8 @@ class HubServerService(BlockchainReaderService):
             env.coin, env.db_dir, self.secondary_name, -1, env.reorg_limit, env.cache_all_claim_txos,
             env.cache_all_tx_hashes, blocking_channel_ids=env.blocking_channel_ids,
             filtering_channel_ids=env.filtering_channel_ids, executor=self._executor,
-            index_address_status=env.index_address_status, merkle_cache_size=env.merkle_cache_size
+            index_address_status=env.index_address_status, merkle_cache_size=env.merkle_cache_size,
+            tx_cache_size=env.tx_cache_size
         )
 
     def clear_caches(self):