diff --git a/CHANGELOG.md b/CHANGELOG.md
index c52b303..0e4245b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,14 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [1.9.0] - 2021-08-17
+
+### Added
+
+- Fixed ability to create Orders with `metadata`
+- Add support for querying Orders by `metadata`
+- Added `transaction_value_eth_gwei` as an alternative way to compute transaction level emissions for ethereum
+
 ## [1.8.0] - 2021-07-20
 
 ### Added
diff --git a/patch_api/__init__.py b/patch_api/__init__.py
index 32918e3..fffe9b3 100644
--- a/patch_api/__init__.py
+++ b/patch_api/__init__.py
@@ -15,7 +15,7 @@
 
 from __future__ import absolute_import
 
-__version__ = "1.8.0"
+__version__ = "1.9.0"
 
 # import ApiClient
 from patch_api.api_client import ApiClient
diff --git a/patch_api/api/estimates_api.py b/patch_api/api/estimates_api.py
index 95d1af0..fc5d274 100644
--- a/patch_api/api/estimates_api.py
+++ b/patch_api/api/estimates_api.py
@@ -148,8 +148,15 @@ def create_bitcoin_estimate_with_http_info(
         path_params = {}
 
         query_params = []
+
+        # do not add duplicate keys to query_params list
+        existing_keys = []
+        for param in query_params:
+            existing_keys.append(param[0])
+
         for key in kwargs:
-            query_params.append([key, kwargs.get(key)])
+            if key not in existing_keys:
+                query_params.append([key, kwargs.get(key)])
 
         header_params = {}
 
@@ -294,8 +301,15 @@ def create_ethereum_estimate_with_http_info(
         path_params = {}
 
         query_params = []
+
+        # do not add duplicate keys to query_params list
+        existing_keys = []
+        for param in query_params:
+            existing_keys.append(param[0])
+
         for key in kwargs:
-            query_params.append([key, kwargs.get(key)])
+            if key not in existing_keys:
+                query_params.append([key, kwargs.get(key)])
 
         header_params = {}
 
@@ -440,8 +454,15 @@ def create_flight_estimate_with_http_info(
         path_params = {}
 
         query_params = []
+
+        # do not add duplicate keys to query_params list
+        existing_keys = []
+        for param in query_params:
+            existing_keys.append(param[0])
+
         for key in kwargs:
-            query_params.append([key, kwargs.get(key)])
+            if key not in existing_keys:
+                query_params.append([key, kwargs.get(key)])
 
         header_params = {}
 
@@ -586,8 +607,15 @@ def create_mass_estimate_with_http_info(
         path_params = {}
 
         query_params = []
+
+        # do not add duplicate keys to query_params list
+        existing_keys = []
+        for param in query_params:
+            existing_keys.append(param[0])
+
         for key in kwargs:
-            query_params.append([key, kwargs.get(key)])
+            if key not in existing_keys:
+                query_params.append([key, kwargs.get(key)])
 
         header_params = {}
 
@@ -732,8 +760,15 @@ def create_shipping_estimate_with_http_info(
         path_params = {}
 
         query_params = []
+
+        # do not add duplicate keys to query_params list
+        existing_keys = []
+        for param in query_params:
+            existing_keys.append(param[0])
+
         for key in kwargs:
-            query_params.append([key, kwargs.get(key)])
+            if key not in existing_keys:
+                query_params.append([key, kwargs.get(key)])
 
         header_params = {}
 
@@ -878,8 +913,15 @@ def create_vehicle_estimate_with_http_info(
         path_params = {}
 
         query_params = []
+
+        # do not add duplicate keys to query_params list
+        existing_keys = []
+        for param in query_params:
+            existing_keys.append(param[0])
+
         for key in kwargs:
-            query_params.append([key, kwargs.get(key)])
+            if key not in existing_keys:
+                query_params.append([key, kwargs.get(key)])
 
         header_params = {}
 
@@ -1017,8 +1059,15 @@ def retrieve_estimate_with_http_info(self, id, **kwargs):  # noqa: E501
             path_params["id"] = local_var_params["id"]  # noqa: E501
 
         query_params = []
+
+        # do not add duplicate keys to query_params list
+        existing_keys = []
+        for param in query_params:
+            existing_keys.append(param[0])
+
         for key in kwargs:
-            query_params.append([key, kwargs.get(key)])
+            if key not in existing_keys:
+                query_params.append([key, kwargs.get(key)])
 
         header_params = {}
 
@@ -1140,11 +1189,18 @@ def retrieve_estimates_with_http_info(self, **kwargs):  # noqa: E501
         path_params = {}
 
         query_params = []
-        for key in kwargs:
-            query_params.append([key, kwargs.get(key)])
         if "page" in local_var_params:
             query_params.append(("page", local_var_params["page"]))  # noqa: E501
 
+        # do not add duplicate keys to query_params list
+        existing_keys = []
+        for param in query_params:
+            existing_keys.append(param[0])
+
+        for key in kwargs:
+            if key not in existing_keys:
+                query_params.append([key, kwargs.get(key)])
+
         header_params = {}
 
         form_params = []
diff --git a/patch_api/api/orders_api.py b/patch_api/api/orders_api.py
index 2bf0532..ccaf0f6 100644
--- a/patch_api/api/orders_api.py
+++ b/patch_api/api/orders_api.py
@@ -141,8 +141,15 @@ def cancel_order_with_http_info(self, id, **kwargs):  # noqa: E501
             path_params["id"] = local_var_params["id"]  # noqa: E501
 
         query_params = []
+
+        # do not add duplicate keys to query_params list
+        existing_keys = []
+        for param in query_params:
+            existing_keys.append(param[0])
+
         for key in kwargs:
-            query_params.append([key, kwargs.get(key)])
+            if key not in existing_keys:
+                query_params.append([key, kwargs.get(key)])
 
         header_params = {}
 
@@ -274,8 +281,15 @@ def create_order_with_http_info(self, create_order_request, **kwargs):  # noqa:
         path_params = {}
 
         query_params = []
+
+        # do not add duplicate keys to query_params list
+        existing_keys = []
+        for param in query_params:
+            existing_keys.append(param[0])
+
         for key in kwargs:
-            query_params.append([key, kwargs.get(key)])
+            if key not in existing_keys:
+                query_params.append([key, kwargs.get(key)])
 
         header_params = {}
 
@@ -413,8 +427,15 @@ def place_order_with_http_info(self, id, **kwargs):  # noqa: E501
             path_params["id"] = local_var_params["id"]  # noqa: E501
 
         query_params = []
+
+        # do not add duplicate keys to query_params list
+        existing_keys = []
+        for param in query_params:
+            existing_keys.append(param[0])
+
         for key in kwargs:
-            query_params.append([key, kwargs.get(key)])
+            if key not in existing_keys:
+                query_params.append([key, kwargs.get(key)])
 
         header_params = {}
 
@@ -543,8 +564,15 @@ def retrieve_order_with_http_info(self, id, **kwargs):  # noqa: E501
             path_params["id"] = local_var_params["id"]  # noqa: E501
 
         query_params = []
+
+        # do not add duplicate keys to query_params list
+        existing_keys = []
+        for param in query_params:
+            existing_keys.append(param[0])
+
         for key in kwargs:
-            query_params.append([key, kwargs.get(key)])
+            if key not in existing_keys:
+                query_params.append([key, kwargs.get(key)])
 
         header_params = {}
 
@@ -591,6 +619,9 @@ def retrieve_orders(self, **kwargs):  # noqa: E501
 
         :param async_req bool: execute request asynchronously
         :param int page:
+        :param str metadata:
+        :param str metadata_example1:
+        :param str metadata_example2:
         :param _preload_content: if False, the urllib3.HTTPResponse object will
                                  be returned without reading/decoding response
                                  data. Default is True.
@@ -616,6 +647,9 @@ def retrieve_orders_with_http_info(self, **kwargs):  # noqa: E501
 
         :param async_req bool: execute request asynchronously
         :param int page:
+        :param str metadata:
+        :param str metadata_example1:
+        :param str metadata_example2:
         :param _return_http_data_only: response data without head status code
                                        and headers
         :param _preload_content: if False, the urllib3.HTTPResponse object will
@@ -632,7 +666,12 @@ def retrieve_orders_with_http_info(self, **kwargs):  # noqa: E501
 
         local_var_params = locals()
 
-        all_params = ["page"]  # noqa: E501
+        all_params = [
+            "page",
+            "metadata",
+            "metadata_example1",
+            "metadata_example2",
+        ]  # noqa: E501
         all_params.append("async_req")
         all_params.append("_return_http_data_only")
         all_params.append("_preload_content")
@@ -666,10 +705,29 @@ def retrieve_orders_with_http_info(self, **kwargs):  # noqa: E501
         path_params = {}
 
         query_params = []
-        for key in kwargs:
-            query_params.append([key, kwargs.get(key)])
         if "page" in local_var_params:
             query_params.append(("page", local_var_params["page"]))  # noqa: E501
+        if "metadata" in local_var_params:
+            query_params.append(
+                ("metadata", local_var_params["metadata"])
+            )  # noqa: E501
+        if "metadata_example1" in local_var_params:
+            query_params.append(
+                ("metadata[example1]", local_var_params["metadata_example1"])
+            )  # noqa: E501
+        if "metadata_example2" in local_var_params:
+            query_params.append(
+                ("metadata[example2]", local_var_params["metadata_example2"])
+            )  # noqa: E501
+
+        # do not add duplicate keys to query_params list
+        existing_keys = []
+        for param in query_params:
+            existing_keys.append(param[0])
+
+        for key in kwargs:
+            if key not in existing_keys:
+                query_params.append([key, kwargs.get(key)])
 
         header_params = {}
 
diff --git a/patch_api/api/preferences_api.py b/patch_api/api/preferences_api.py
index d45e3fb..8160bdc 100644
--- a/patch_api/api/preferences_api.py
+++ b/patch_api/api/preferences_api.py
@@ -146,8 +146,15 @@ def create_preference_with_http_info(
         path_params = {}
 
         query_params = []
+
+        # do not add duplicate keys to query_params list
+        existing_keys = []
+        for param in query_params:
+            existing_keys.append(param[0])
+
         for key in kwargs:
-            query_params.append([key, kwargs.get(key)])
+            if key not in existing_keys:
+                query_params.append([key, kwargs.get(key)])
 
         header_params = {}
 
@@ -285,8 +292,15 @@ def delete_preference_with_http_info(self, id, **kwargs):  # noqa: E501
             path_params["id"] = local_var_params["id"]  # noqa: E501
 
         query_params = []
+
+        # do not add duplicate keys to query_params list
+        existing_keys = []
+        for param in query_params:
+            existing_keys.append(param[0])
+
         for key in kwargs:
-            query_params.append([key, kwargs.get(key)])
+            if key not in existing_keys:
+                query_params.append([key, kwargs.get(key)])
 
         header_params = {}
 
@@ -415,8 +429,15 @@ def retrieve_preference_with_http_info(self, id, **kwargs):  # noqa: E501
             path_params["id"] = local_var_params["id"]  # noqa: E501
 
         query_params = []
+
+        # do not add duplicate keys to query_params list
+        existing_keys = []
+        for param in query_params:
+            existing_keys.append(param[0])
+
         for key in kwargs:
-            query_params.append([key, kwargs.get(key)])
+            if key not in existing_keys:
+                query_params.append([key, kwargs.get(key)])
 
         header_params = {}
 
@@ -538,11 +559,18 @@ def retrieve_preferences_with_http_info(self, **kwargs):  # noqa: E501
         path_params = {}
 
         query_params = []
-        for key in kwargs:
-            query_params.append([key, kwargs.get(key)])
         if "page" in local_var_params:
             query_params.append(("page", local_var_params["page"]))  # noqa: E501
 
+        # do not add duplicate keys to query_params list
+        existing_keys = []
+        for param in query_params:
+            existing_keys.append(param[0])
+
+        for key in kwargs:
+            if key not in existing_keys:
+                query_params.append([key, kwargs.get(key)])
+
         header_params = {}
 
         form_params = []
diff --git a/patch_api/api/projects_api.py b/patch_api/api/projects_api.py
index 64fa2b4..438ac43 100644
--- a/patch_api/api/projects_api.py
+++ b/patch_api/api/projects_api.py
@@ -141,8 +141,15 @@ def retrieve_project_with_http_info(self, id, **kwargs):  # noqa: E501
             path_params["id"] = local_var_params["id"]  # noqa: E501
 
         query_params = []
+
+        # do not add duplicate keys to query_params list
+        existing_keys = []
+        for param in query_params:
+            existing_keys.append(param[0])
+
         for key in kwargs:
-            query_params.append([key, kwargs.get(key)])
+            if key not in existing_keys:
+                query_params.append([key, kwargs.get(key)])
 
         header_params = {}
 
@@ -270,8 +277,6 @@ def retrieve_projects_with_http_info(self, **kwargs):  # noqa: E501
         path_params = {}
 
         query_params = []
-        for key in kwargs:
-            query_params.append([key, kwargs.get(key)])
         if "page" in local_var_params:
             query_params.append(("page", local_var_params["page"]))  # noqa: E501
         if "country" in local_var_params:
@@ -283,6 +288,15 @@ def retrieve_projects_with_http_info(self, **kwargs):  # noqa: E501
                 ("minimum_available_mass", local_var_params["minimum_available_mass"])
             )  # noqa: E501
 
+        # do not add duplicate keys to query_params list
+        existing_keys = []
+        for param in query_params:
+            existing_keys.append(param[0])
+
+        for key in kwargs:
+            if key not in existing_keys:
+                query_params.append([key, kwargs.get(key)])
+
         header_params = {}
 
         form_params = []
diff --git a/patch_api/api_client.py b/patch_api/api_client.py
index 5beb1c3..c3e4256 100644
--- a/patch_api/api_client.py
+++ b/patch_api/api_client.py
@@ -91,7 +91,7 @@ def __init__(
             self.default_headers[header_name] = header_value
         self.cookie = cookie
         # Set default User-Agent.
-        self.user_agent = "OpenAPI-Generator/1.8.0/python"
+        self.user_agent = "OpenAPI-Generator/1.9.0/python"
 
     def __del__(self):
         if self._pool:
diff --git a/patch_api/configuration.py b/patch_api/configuration.py
index 80ed119..3ae9bee 100644
--- a/patch_api/configuration.py
+++ b/patch_api/configuration.py
@@ -341,7 +341,7 @@ def to_debug_report(self):
             "OS: {env}\n"
             "Python Version: {pyversion}\n"
             "Version of the API: v1\n"
-            "SDK Package Version: 1.8.0".format(env=sys.platform, pyversion=sys.version)
+            "SDK Package Version: 1.9.0".format(env=sys.platform, pyversion=sys.version)
         )
 
     def get_host_settings(self):
diff --git a/patch_api/models/estimate.py b/patch_api/models/estimate.py
index e767292..3792db3 100644
--- a/patch_api/models/estimate.py
+++ b/patch_api/models/estimate.py
@@ -137,7 +137,7 @@ def production(self, production):
     def type(self):
         """Gets the type of this Estimate.  # noqa: E501
 
-        The type of estimate. Available types are mass, flight, shipping, and vehicle.  # noqa: E501
+        The type of estimate. Available types are mass, flight, shipping, vehicle, and crypto.  # noqa: E501
 
         :return: The type of this Estimate.  # noqa: E501
         :rtype: str
@@ -148,7 +148,7 @@ def type(self):
     def type(self, type):
         """Sets the type of this Estimate.
 
-        The type of estimate. Available types are mass, flight, shipping, and vehicle.  # noqa: E501
+        The type of estimate. Available types are mass, flight, shipping, vehicle, and crypto.  # noqa: E501
 
         :param type: The type of this Estimate.  # noqa: E501
         :type: str
diff --git a/patch_api/rest.py b/patch_api/rest.py
index f67e65f..20090ee 100644
--- a/patch_api/rest.py
+++ b/patch_api/rest.py
@@ -25,6 +25,7 @@
 import six
 from six.moves.urllib.parse import urlencode
 import urllib3
+import urllib.parse
 
 from patch_api.exceptions import ApiException, ApiValueError
 
@@ -110,6 +111,60 @@ def __init__(self, api_key, configuration, pools_size=4, maxsize=None):
                 **addition_pool_args
             )
 
+    def recursive_urlencode(self, d):
+        """URL-encode a multidimensional dictionary.
+
+        >>> data = {'a': 'b&c', 'd': {'e': {'f&g': 'h*i'}}, 'j': 'k'}
+        >>> recursive_urlencode(data)
+        u'a=b%26c&j=k&d[e][f%26g]=h%2Ai'
+        """
+
+        def recursion(d, base=[]):
+            pairs = []
+
+            for key, value in d.items():
+                new_base = base + [key]
+                if hasattr(value, "values"):
+                    pairs += recursion(value, new_base)
+                else:
+                    new_pair = None
+                    if len(new_base) > 1:
+                        first = urllib.parse.quote(new_base.pop(0))
+                        rest = map(lambda x: urllib.parse.quote(x), new_base)
+                        new_pair = "%s[%s]=%s" % (
+                            first,
+                            "][".join(rest),
+                            urllib.parse.quote(str(value)),
+                        )
+                    else:
+                        new_pair = "%s=%s" % (
+                            urllib.parse.quote(str(key)),
+                            urllib.parse.quote(str(value)),
+                        )
+                    pairs.append(new_pair)
+            return pairs
+
+        return "&".join(recursion(d))
+
+    def encoded_query_params(self, query_params):
+        if not query_params:
+            return ""
+
+        final_query_params = ""
+        for key, value in query_params:
+            if isinstance(value, dict):
+                nested_param = {}
+                nested_param[key] = value
+                final_query_params += self.recursive_urlencode(nested_param)
+                query_params.remove((key, value))
+
+        if query_params:
+            if final_query_params:
+                final_query_params += "&"
+            final_query_params += urlencode(query_params)
+
+        return "?" + final_query_params
+
     def request(
         self,
         method,
@@ -170,8 +225,7 @@ def request(
         try:
             # For `POST`, `PUT`, `PATCH`, `OPTIONS`, `DELETE`
             if method in ["POST", "PUT", "PATCH", "OPTIONS", "DELETE"]:
-                if query_params:
-                    url += "?" + urlencode(query_params)
+                url += self.encoded_query_params(query_params)
                 if re.search("json", headers["Content-Type"], re.IGNORECASE):
                     request_body = None
                     if body is not None:
@@ -231,10 +285,10 @@ def request(
                     raise ApiException(status=0, reason=msg)
             # For `GET`, `HEAD`
             else:
+                url += self.encoded_query_params(query_params)
                 r = self.pool_manager.request(
                     method,
                     url,
-                    fields=query_params,
                     preload_content=_preload_content,
                     timeout=timeout,
                     headers=headers,
diff --git a/setup.py b/setup.py
index 2944ae0..f4070af 100644
--- a/setup.py
+++ b/setup.py
@@ -12,7 +12,7 @@
 from setuptools import setup, find_packages  # noqa: H301
 
 NAME = "patch-api"
-VERSION = "1.8.0"
+VERSION = "1.9.0"
 # To install the library, run the following
 #
 # python setup.py install
diff --git a/test/test_estimates_api.py b/test/test_estimates_api.py
index 34be1fb..84f0c9b 100644
--- a/test/test_estimates_api.py
+++ b/test/test_estimates_api.py
@@ -53,8 +53,8 @@ def test_create_and_retrieve_flight_estimate(self):
             distance_m=distance_m, create_order=True
         )
         self.assertEqual(estimate.data.type, "flight")
-        self.assertEqual(estimate.data.order.mass_g, 1031697)
-        self.assertEqual(estimate.data.mass_g, 1031697)
+        self.assertEqual(estimate.data.order.mass_g, 1000622)
+        self.assertEqual(estimate.data.mass_g, 1000622)
 
         retrieved_estimate = self.api.retrieve_estimate(id=estimate.data.id)
         self.assertTrue(retrieved_estimate)
@@ -75,7 +75,7 @@ def test_create_and_retrieve_shipping_estimate(self):
         )
         self.assertEqual(estimate.data.order, None)
         self.assertEqual(estimate.data.type, "shipping")
-        self.assertEqual(estimate.data.mass_g, 373)
+        self.assertEqual(estimate.data.mass_g, 249)
 
         retrieved_estimate = self.api.retrieve_estimate(id=estimate.data.id)
         self.assertTrue(retrieved_estimate)
diff --git a/test/test_orders_api.py b/test/test_orders_api.py
index ba1b37c..2520384 100644
--- a/test/test_orders_api.py
+++ b/test/test_orders_api.py
@@ -77,6 +77,23 @@ def test_retrieve_orders(self):
             self.assertEqual(retrieved_order.metadata, {})
             self.assertTrue(isinstance(retrieved_order.allocations, list))
 
+    def test_create_and_retrieve_order_via_metadata(self):
+        """Test case for create_order and retrieve_orders with metadata"""
+        mass_g = 100
+        metadata = {"external_id": "abc-123"}
+        order = self.api.create_order(mass_g=mass_g, metadata=metadata)
+
+        self.assertTrue(order)
+        self.assertEqual(order.data.mass_g, 100)
+        self.assertEqual(order.data.metadata, {"external_id": "abc-123"})
+
+        retrieved_orders = self.api.retrieve_orders(
+            metadata={"external_id": "abc-"}
+        ).data
+        self.assertGreater(len(retrieved_orders), 0)
+        for retrieved_order in retrieved_orders:
+            self.assertTrue("external_id" in retrieved_order.metadata)
+
 
 if __name__ == "__main__":
     unittest.main()
diff --git a/test/test_projects_api.py b/test/test_projects_api.py
index a01aa6e..11f2d90 100644
--- a/test/test_projects_api.py
+++ b/test/test_projects_api.py
@@ -55,7 +55,7 @@ def test_retrieve_projects(self):
             self.assertGreater(project.average_price_per_tonne_cents_usd, 0)
             self.assertGreater(project.remaining_mass_g, 0)
             self.assertEqual(project.standard, None)
-            self.assertEqual(project.name, "Patch's Biomass Test Offset Project")
+            self.assertRegex(project.name, r"Test Offset Project")
             self.assertTrue(project.description)
             self.assertEqual(project.country, "US")
             self.assertEqual(project.type, "biomass")
diff --git a/test/test_rest.py b/test/test_rest.py
new file mode 100644
index 0000000..490b7a9
--- /dev/null
+++ b/test/test_rest.py
@@ -0,0 +1,58 @@
+from __future__ import absolute_import
+
+from patch_api.configuration import Configuration
+from patch_api import rest
+
+import unittest
+import os
+
+from patch_api.api_client import ApiClient
+
+
+class TestRESTClientObject(unittest.TestCase):
+    def test_recursive_urlencode(self):
+        """Test that the correct query params get encoded"""
+
+        api_key = os.environ.get("SANDBOX_API_KEY")
+        configuration = Configuration()
+        client = rest.RESTClientObject(api_key, configuration)
+
+        encoded_params = client.recursive_urlencode({})
+        self.assertEqual(encoded_params, "")
+
+        encoded_params = client.recursive_urlencode({"page": 1})
+        self.assertEqual(encoded_params, "page=1")
+
+        encoded_params = client.recursive_urlencode({"string": "value"})
+        self.assertEqual(encoded_params, "string=value")
+
+        encoded_params = client.recursive_urlencode(
+            {"multiple": "values", "top": "level"}
+        )
+        self.assertEqual(encoded_params, "multiple=values&top=level")
+
+        encoded_params = client.recursive_urlencode({"metadata": {"some": "arg"}})
+        self.assertEqual(encoded_params, "metadata[some]=arg")
+
+        encoded_params = client.recursive_urlencode(
+            {"deeply": {"nested": {"hash": {"of": "args"}}}}
+        )
+        self.assertEqual(encoded_params, "deeply[nested][hash][of]=args")
+
+    def test_encoded_query_params(self):
+        """Test that the correct query params get encoded"""
+
+        api_key = os.environ.get("SANDBOX_API_KEY")
+        configuration = Configuration()
+        client = rest.RESTClientObject(api_key, configuration)
+
+        encoded_params = client.encoded_query_params([])
+        self.assertEqual(encoded_params, "")
+
+        encoded_params = client.encoded_query_params([("mass_g", 100)])
+        self.assertEqual(encoded_params, "?mass_g=100")
+
+        encoded_params = client.encoded_query_params(
+            [("mass_g", 100), ("metadata", {"external_id": "abc-123"})]
+        )
+        self.assertEqual(encoded_params, "?metadata[external_id]=abc-123&mass_g=100")