diff --git a/bigchaindb/web/views/parameters.py b/bigchaindb/web/views/parameters.py
new file mode 100644
index 00000000..9968a659
--- /dev/null
+++ b/bigchaindb/web/views/parameters.py
@@ -0,0 +1,30 @@
+import re
+
+
+def valid_txid(txid):
+    if re.match('^[a-fA-F0-9]{64}$', txid):
+        return txid.lower()
+    raise ValueError("Invalid hash")
+
+
+def valid_bool(val):
+    if val == 'true':
+        return True
+    if val == 'false':
+        return False
+    raise ValueError('Boolean value must be "true" or "false" (lowercase)')
+
+
+def valid_ed25519(key):
+    if (re.match('^[1-9a-zA-Z]{43,44}$', key) and not
+        re.match('.*[Il0O]', key)):
+        return key
+    raise ValueError("Invalid base58 ed25519 key")
+
+
+def valid_operation(op):
+    if op == 'CREATE':
+        return 'CREATE'
+    if op == 'TRANSFER':
+        return 'TRANSFER'
+    raise ValueError('Operation must be "CREATE" or "TRANSFER')
diff --git a/bigchaindb/web/views/transactions.py b/bigchaindb/web/views/transactions.py
index fa544f65..e61a791f 100644
--- a/bigchaindb/web/views/transactions.py
+++ b/bigchaindb/web/views/transactions.py
@@ -5,9 +5,11 @@ For more information please refer to the documentation on ReadTheDocs:
    http-client-server-api.html
 """
 import logging
+import re
 
 from flask import current_app, request
-from flask_restful import Resource
+from flask_restful import Resource, reqparse
+
 
 from bigchaindb.common.exceptions import (
     AmountError,
@@ -25,6 +27,7 @@ from bigchaindb.common.exceptions import (
 import bigchaindb
 from bigchaindb.models import Transaction
 from bigchaindb.web.views.base import make_error
+from bigchaindb.web.views import parameters
 
 logger = logging.getLogger(__name__)
 
@@ -51,6 +54,16 @@ class TransactionApi(Resource):
 
 
 class TransactionListApi(Resource):
+    def get(self):
+        parser = reqparse.RequestParser()
+        parser.add_argument('operation', type=parameters.valid_operation)
+        parser.add_argument('unspent', type=parameters.valid_bool)
+        parser.add_argument('public_key', type=parameters.valid_ed25519,
+                            action="append")
+        parser.add_argument('asset_id', type=parameters.valid_txid)
+        args = parser.parse_args()
+        return args
+
     def post(self):
         """API endpoint to push transactions to the Federation.
 
diff --git a/tests/web/test_parameters.py b/tests/web/test_parameters.py
new file mode 100644
index 00000000..4044a273
--- /dev/null
+++ b/tests/web/test_parameters.py
@@ -0,0 +1,79 @@
+import pytest
+
+
+def test_valid_txid():
+    from bigchaindb.web.views.parameters import valid_txid
+
+    valid = ['18ac3e7343f016890c510e93f935261169d9e3f565436429830faf0934f4f8e4',
+             '18AC3E7343F016890C510E93F935261169D9E3F565436429830FAF0934F4F8E4']
+    for h in valid:
+        assert valid_txid(h) == h.lower()
+
+    non = ['18ac3e7343f016890c510e93f935261169d9e3f565436429830faf0934f4f8e',
+           '18ac3e7343f016890c510e93f935261169d9e3f565436429830faf0934f4f8e45',
+           '18ac3e7343f016890c510e93f935261169d9e3f565436429830faf0934f4f8eg',
+           '18ac3e7343f016890c510e93f935261169d9e3f565436429830faf0934f4f8e ',
+           '']
+    for h in non:
+        with pytest.raises(ValueError):
+            valid_txid(h)
+
+
+def test_valid_bool():
+    from bigchaindb.web.views.parameters import valid_bool
+
+    assert valid_bool('true') == True
+    valid_bool('false') == False
+
+    with pytest.raises(ValueError):
+        valid_bool('TRUE')
+    with pytest.raises(ValueError):
+        valid_bool('FALSE')
+    with pytest.raises(ValueError):
+        valid_bool('0')
+    with pytest.raises(ValueError):
+        valid_bool('1')
+    with pytest.raises(ValueError):
+        valid_bool('yes')
+    with pytest.raises(ValueError):
+        valid_bool('no')
+
+
+def test_valid_ed25519():
+    from bigchaindb.web.views.parameters import valid_ed25519
+
+    valid = ['123456789abcdefghijkmnopqrstuvwxyz1111111111',
+             '123456789ABCDEFGHJKLMNPQRSTUVWXYZ1111111111']
+    for h in valid:
+        assert valid_ed25519(h) == h
+
+    with pytest.raises(ValueError):
+        valid_ed25519('1234556789abcdefghijkmnopqrstuvwxyz1111111')
+    with pytest.raises(ValueError):
+        valid_ed25519('1234556789abcdefghijkmnopqrstuvwxyz1111111111')
+    with pytest.raises(ValueError):
+        valid_ed25519('123456789abcdefghijkmnopqrstuvwxyz111111111l')
+    with pytest.raises(ValueError):
+        valid_ed25519('123456789abcdefghijkmnopqrstuvwxyz111111111I')
+    with pytest.raises(ValueError):
+        valid_ed25519('1234556789abcdefghijkmnopqrstuvwxyz11111111O')
+    with pytest.raises(ValueError):
+        valid_ed25519('1234556789abcdefghijkmnopqrstuvwxyz111111110')
+
+
+def test_valid_operation():
+    from bigchaindb.web.views.parameters import valid_operation
+
+    assert valid_operation('CREATE') == 'CREATE'
+    assert valid_operation('TRANSFER') == 'TRANSFER'
+
+    with pytest.raises(ValueError):
+        valid_operation('create')
+    with pytest.raises(ValueError):
+        valid_operation('transfer')
+    with pytest.raises(ValueError):
+        valid_operation('GENESIS')
+    with pytest.raises(ValueError):
+        valid_operation('blah')
+    with pytest.raises(ValueError):
+        valid_operation('')