diff --git a/accounting/decorators.py b/accounting/decorators.py
index da4cb55ff6a82ab310eb4b62dc6ce7a957d84fa1..634767e9e95554ef212f93c738075cb9352de0b4 100644
--- a/accounting/decorators.py
+++ b/accounting/decorators.py
@@ -19,7 +19,11 @@ def jsonify_exceptions(func):
         try:
             return func(*args, **kw)
         except AccountingException as exc:
-            return jsonify(error=exc)
+            response = jsonify(error=exc)
+
+            response.status_code = exc.http_code
+
+            return response
 
     return wrapper
 
diff --git a/accounting/exceptions.py b/accounting/exceptions.py
index 6d751cafd0c4da6ced7276144741ee4a6b1513f0..42b179f902319019c7e3f92256cc2c0b6bd59d86 100644
--- a/accounting/exceptions.py
+++ b/accounting/exceptions.py
@@ -7,6 +7,7 @@ class AccountingException(Exception):
     Used as a base for exceptions that are returned to the caller via the
     jsonify_exceptions decorator
     '''
+    http_code = 500
     def __init__(self, message, **kw):
         self.message = message
         for key, value in kw.items():
@@ -14,12 +15,12 @@ class AccountingException(Exception):
 
 
 class TransactionNotFound(AccountingException):
-    pass
+    http_code = 404
 
 
 class LedgerNotBalanced(AccountingException):
-    pass
+    http_code = 400
 
 
 class TransactionIDCollision(AccountingException):
-    pass
+    http_code = 400
diff --git a/accounting/storage/ledgercli.py b/accounting/storage/ledgercli.py
index 919d8f722d6e62d0455c9e84097dc76aae2cec60..eb864453c9bf2e93ed2a5dc0a2340cb69deda96e 100644
--- a/accounting/storage/ledgercli.py
+++ b/accounting/storage/ledgercli.py
@@ -173,6 +173,18 @@ class Ledger(Storage):
         with open(self.ledger_file, 'ab') as f:
             f.write(output)
 
+        # Check to see that no errors were introduced
+        try:
+            self.get_transactions()
+        except AccountingException as exc:
+            # TODO: Do a hard reset on the repository using Repository.reset,
+            # this is on hold because of
+            # https://github.com/libgit2/pygit2/issues/271.
+            # This solution will work in the meantime
+            self.delete_transaction(transaction.id)
+            setattr(exc, 'transaction', transaction)
+            raise exc
+
         self.commit_changes('Added transaction %s' % transaction.id)
 
         _log.info('Added transaction %s', transaction.id)
diff --git a/accounting/tests/test_transactions.py b/accounting/tests/test_transactions.py
index 03ea2fcbf19c5d0883f63ea7e814cb96e965054c..f7d9bd1df9ca8221e3f793a21fb476509791e67d 100644
--- a/accounting/tests/test_transactions.py
+++ b/accounting/tests/test_transactions.py
@@ -9,6 +9,7 @@ import copy
 import uuid
 
 from datetime import datetime
+from decimal import Decimal
 
 from flask import json
 
@@ -17,7 +18,7 @@ from accounting.web import app, init_ledger
 from accounting.transport import AccountingEncoder, AccountingDecoder
 from accounting.models import Transaction, Posting, Amount
 
-logging.basicConfig(level=logging.DEBUG)
+#logging.basicConfig(level=logging.DEBUG)
 
 
 class TransactionTestCase(unittest.TestCase):
@@ -263,13 +264,36 @@ class TransactionTestCase(unittest.TestCase):
             ]
         )
 
-        self._post_json('/transaction', transaction)
+        response = self._post_json('/transaction', transaction, expect=400)
 
-        response = self._get_json('/transaction')
+        self.assertEqual(response['error']['type'], 'LedgerNotBalanced')
 
-        import pdb; pdb.set_trace()
+    def test_update_transaction_amounts(self):
+        transaction = self._add_simple_transaction()
+        response = self._get_json(
+            '/transaction/' + transaction.id)
+
+        transaction = response['transaction']
+
+        for posting in transaction.postings:
+            posting.amount.amount *= Decimal(1.50)
+
+        response = self._post_json('/transaction/' + transaction.id,
+                                   {'transaction': transaction})
+
+        self.assertEqual(response['status'], 'OK')
+
+        response = self._get_json('/transaction/' + transaction.id)
+
+        self.assertEqual(response['transaction'], transaction)
+
+    def test_delete_nonexistent_transaction(self):
+        response = self._open_json('DELETE', '/transaction/I-do-not-exist',
+                                   expect=404)
+
+        self.assertEqual(response['error']['type'], 'TransactionNotFound')
 
-    def test_update_transaction_amounts(self): pass
+    def test_post_transaction_with_metadata(self): pass
 
 
 if __name__ == '__main__':
diff --git a/accounting/transport.py b/accounting/transport.py
index e838be9edc151161607571de97cda4843c1dbb78..ac155b7ce11622c0667b9dc6c06f8c12b4d50e60 100644
--- a/accounting/transport.py
+++ b/accounting/transport.py
@@ -44,7 +44,8 @@ class AccountingEncoder(json.JSONEncoder):
         elif isinstance(o, AccountingException):
             return dict(
                 type=o.__class__.__name__,
-                message=o.message
+                message=o.message,
+                transaction=getattr(o, 'transaction', None)
             )
 
         return json.JSONEncoder.default(self, o)