diff --git a/spec/factories/plan.rb b/spec/factories/plan.rb
index 5d43eb8..d7727fa 100644
--- a/spec/factories/plan.rb
+++ b/spec/factories/plan.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 FactoryBot.define do
-  factory :plan, class: OpenStruct do
+  factory :create_plan, class: OpenStruct do
     name { 'plan1' }
     invoice_display_name { 'PLN1' }
     code { 'plan_code' }
diff --git a/spec/fixtures/api/fee.json b/spec/fixtures/api/fee.json
index 8346885..cb6ffe8 100644
--- a/spec/fixtures/api/fee.json
+++ b/spec/fixtures/api/fee.json
@@ -11,7 +11,10 @@
       "code": "fee_code",
       "name": "Fee Code",
       "invoice_display_name": "Fee C1",
-      "group_invoice_display_name": "Transactions - ACH"
+      "group_invoice_display_name": "Transactions - ACH",
+      "grouped_by": {
+        "agent_name": "aragorn"
+      }
     },
     "amount_cents": 120,
     "amount_currency": "EUR",
diff --git a/spec/fixtures/api/plan.json b/spec/fixtures/api/plan.json
new file mode 100644
index 0000000..703aefc
--- /dev/null
+++ b/spec/fixtures/api/plan.json
@@ -0,0 +1,41 @@
+{
+  "plan": {
+    "lago_id": "1a901a90-1a90-1a90-1a90-1a901a901a90",
+    "name": "plan1",
+    "invoice_display_name": "PLN1",
+    "created_at": "2022-04-29T08:59:51Z",
+    "code": "plan_code",
+    "interval": "monthly",
+    "description": "desc",
+    "amount_cents": 100,
+    "amount_currency": "EUR",
+    "trial_period": 2,
+    "pay_in_advance": false,
+    "bill_charges_monthly": false,
+    "active_subscriptions_count": 0,
+    "draft_invoices_count": 0,
+    "charges": [
+      {
+        "lago_id": "1a901a90-1a90-1a90-1a90-1a901a901a90",
+        "lago_billable_metric_id": "1a901a90-1a90-1a90-1a90-1a901a901a90",
+        "billable_metric_code": "bm_code",
+        "created_at": "2022-04-29T08:59:51Z",
+        "charge_model": "standard",
+        "pay_in_advance": false,
+        "invoiceable": true,
+        "min_amount_cents": 0,
+        "properties": {
+          "amount": "0.22",
+          "grouped_by": [
+            "agent_name"
+          ]
+        }
+      }
+    ],
+    "taxes": [
+      {
+        "code": "tax_code"
+      }
+    ]
+  }
+}
diff --git a/spec/fixtures/api/plans.json b/spec/fixtures/api/plans.json
new file mode 100644
index 0000000..8da4129
--- /dev/null
+++ b/spec/fixtures/api/plans.json
@@ -0,0 +1,51 @@
+{
+  "plans": [
+    {
+      "lago_id": "1a901a90-1a90-1a90-1a90-1a901a901a90",
+      "name": "plan1",
+      "invoice_display_name": "PLN1",
+      "created_at": "2022-04-29T08:59:51Z",
+      "code": "plan_code",
+      "interval": "monthly",
+      "description": "desc",
+      "amount_cents": 100,
+      "amount_currency": "EUR",
+      "trial_period": 2,
+      "pay_in_advance": false,
+      "bill_charges_monthly": false,
+      "active_subscriptions_count": 0,
+      "draft_invoices_count": 0,
+      "charges": [
+        {
+          "lago_id": "1a901a90-1a90-1a90-1a90-1a901a901a90",
+          "lago_billable_metric_id": "1a901a90-1a90-1a90-1a90-1a901a901a90",
+          "billable_metric_code": "bm_code",
+          "created_at": "2022-04-29T08:59:51Z",
+          "charge_model": "standard",
+          "invoice_display_name": "Charge 1",
+          "pay_in_advance": false,
+          "invoiceable": true,
+          "min_amount_cents": 0,
+          "properties": {
+            "amount": "0.22",
+            "grouped_by": [
+              "agent_name"
+            ]
+          }
+        }
+      ],
+      "taxes": [
+        {
+          "code": "tax_code"
+        }
+      ]
+    }
+  ],
+  "meta": {
+    "current_page": 1,
+    "next_page": 2,
+    "prev_page": null,
+    "total_pages": 7,
+    "total_count": 63
+  }
+}
diff --git a/spec/lago/api/resources/plan_spec.rb b/spec/lago/api/resources/plan_spec.rb
index 968ebb3..02163ad 100644
--- a/spec/lago/api/resources/plan_spec.rb
+++ b/spec/lago/api/resources/plan_spec.rb
@@ -6,41 +6,14 @@
   subject(:resource) { described_class.new(client) }
 
   let(:client) { Lago::Api::Client.new }
-  let(:factory_plan) { build(:plan) }
-  let(:response) do
-    {
-      'plan' => {
-        'lago_id' => 'this-is-lago-id',
-        'name' => factory_plan.name,
-        'invoice_display_name' => factory_plan.invoice_display_name,
-        'created_at' => '2022-04-29T08:59:51Z',
-        'code' => factory_plan.code,
-        'interval' => factory_plan.amount_cents,
-        'description' => factory_plan.amount_currency,
-        'amount_cents' => factory_plan.expiration,
-        'amount_currency' => factory_plan.expiration_duration,
-        'trial_period' => 2,
-        'pay_in_advance' => false,
-        'bill_charges_monthly' => false,
-        'active_subscriptions_count' => 0,
-        'draft_invoices_count' => 0,
-        'charges' => [
-          {
-            'lago_id' => 'id1',
-            'lago_billable_metric_id' => factory_plan.charges.first[:lago_billable_metric_id],
-            'billable_metric_code' => 'bm_code',
-            'created_at' => '2022-04-29T08:59:51Z',
-            'charge_model' => factory_plan.charges.first[:charge_model],
-            'pay_in_advance' => false,
-            'invoiceable' => true,
-            'min_amount_cents' => 0,
-            'properties' => factory_plan.charges.first[:properties],
-          },
-        ],
-        'taxes' => [{ 'code' => 'tax_code' }],
-      }
-    }.to_json
-  end
+
+  let(:plan_response) { load_fixture('plan') }
+  let(:plan_json) { JSON.parse(plan_response)['plan'] }
+  let(:plan_id) { plan_json['lago_id'] }
+  let(:plan_code) { plan_json['code'] }
+  let(:plan_name) { plan_json['name'] }
+  let(:plan_dsplay_name) { plan_json['invoice_display_name'] }
+
   let(:error_response) do
     {
       'status' => 422,
@@ -51,7 +24,7 @@
 
   describe '#create' do
     let(:tax_codes) { ['tax_code'] }
-    let(:params) { factory_plan.to_h.merge(tax_codes: tax_codes) }
+    let(:params) { create(:create_plan).to_h.merge(tax_codes: tax_codes) }
     let(:body) do
       { 'plan' => params }
     end
@@ -60,15 +33,15 @@
       before do
         stub_request(:post, 'https://api.getlago.com/api/v1/plans')
           .with(body: body)
-          .to_return(body: response, status: 200)
+          .to_return(body: plan_response, status: 200)
       end
 
       it 'returns an plan' do
         plan = resource.create(params)
 
-        expect(plan.lago_id).to eq('this-is-lago-id')
-        expect(plan.name).to eq(factory_plan.name)
-        expect(plan.invoice_display_name).to eq(factory_plan.invoice_display_name)
+        expect(plan.lago_id).to eq(plan_id)
+        expect(plan.name).to eq(plan_name)
+        expect(plan.invoice_display_name).to eq(plan_dsplay_name)
         expect(plan.taxes.map(&:code)).to eq(tax_codes)
       end
     end
@@ -87,38 +60,33 @@
   end
 
   describe '#update' do
-    let(:params) { factory_plan.to_h }
-    let(:body) do
-      {
-        'plan' => factory_plan.to_h,
-      }
-    end
+    let(:params) { create(:create_plan).to_h }
 
     context 'when plan is successfully updated' do
       before do
-        stub_request(:put, "https://api.getlago.com/api/v1/plans/#{factory_plan.code}")
-          .with(body: body)
-          .to_return(body: response, status: 200)
+        stub_request(:put, "https://api.getlago.com/api/v1/plans/#{plan_code}")
+          .with(body: { plan: params })
+          .to_return(body: plan_response, status: 200)
       end
 
       it 'returns an plan' do
-        plan = resource.update(params, factory_plan.code)
+        plan = resource.update(params, plan_code)
 
-        expect(plan.lago_id).to eq('this-is-lago-id')
-        expect(plan.name).to eq(factory_plan.name)
-        expect(plan.invoice_display_name).to eq(factory_plan.invoice_display_name)
+        expect(plan.lago_id).to eq(plan_id)
+        expect(plan.name).to eq(plan_name)
+        expect(plan.invoice_display_name).to eq(plan_dsplay_name)
       end
     end
 
     context 'when plan failed to update' do
       before do
-        stub_request(:put, "https://api.getlago.com/api/v1/plans/#{factory_plan.code}")
-          .with(body: body)
+        stub_request(:put, "https://api.getlago.com/api/v1/plans/#{plan_code}")
+          .with(body: { plan: params })
           .to_return(body: error_response, status: 422)
       end
 
       it 'raises an error' do
-        expect { resource.update(params, factory_plan.code) }.to raise_error Lago::Api::HttpError
+        expect { resource.update(params, plan_code) }.to raise_error Lago::Api::HttpError
       end
     end
   end
@@ -126,27 +94,27 @@
   describe '#get' do
     context 'when plan is successfully fetched' do
       before do
-        stub_request(:get, "https://api.getlago.com/api/v1/plans/#{factory_plan.code}")
-          .to_return(body: response, status: 200)
+        stub_request(:get, "https://api.getlago.com/api/v1/plans/#{plan_code}")
+          .to_return(body: plan_response, status: 200)
       end
 
       it 'returns an plan' do
-        plan = resource.get(factory_plan.code)
+        plan = resource.get(plan_code)
 
-        expect(plan.lago_id).to eq('this-is-lago-id')
-        expect(plan.name).to eq(factory_plan.name)
-        expect(plan.invoice_display_name).to eq(factory_plan.invoice_display_name)
+        expect(plan.lago_id).to eq(plan_id)
+        expect(plan.name).to eq(plan_name)
+        expect(plan.invoice_display_name).to eq(plan_dsplay_name)
       end
     end
 
     context 'when there is an issue' do
       before do
-        stub_request(:get, "https://api.getlago.com/api/v1/plans/#{factory_plan.code}")
+        stub_request(:get, "https://api.getlago.com/api/v1/plans/#{plan_code}")
           .to_return(body: error_response, status: 422)
       end
 
       it 'raises an error' do
-        expect { resource.get(factory_plan.code) }.to raise_error Lago::Api::HttpError
+        expect { resource.get(plan_code) }.to raise_error Lago::Api::HttpError
       end
     end
   end
@@ -154,89 +122,48 @@
   describe '#destroy' do
     context 'when plan is successfully destroyed' do
       before do
-        stub_request(:delete, "https://api.getlago.com/api/v1/plans/#{factory_plan.code}")
-          .to_return(body: response, status: 200)
+        stub_request(:delete, "https://api.getlago.com/api/v1/plans/#{plan_code}")
+          .to_return(body: plan_response, status: 200)
       end
 
       it 'returns an plan' do
-        plan = resource.destroy(factory_plan.code)
+        plan = resource.destroy(plan_code)
 
-        expect(plan.lago_id).to eq('this-is-lago-id')
-        expect(plan.name).to eq(factory_plan.name)
-        expect(plan.invoice_display_name).to eq(factory_plan.invoice_display_name)
+        expect(plan.lago_id).to eq(plan_id)
+        expect(plan.name).to eq(plan_name)
+        expect(plan.invoice_display_name).to eq(plan_dsplay_name)
       end
     end
 
     context 'when there is an issue' do
       before do
-        stub_request(:delete, "https://api.getlago.com/api/v1/plans/#{factory_plan.code}")
+        stub_request(:delete, "https://api.getlago.com/api/v1/plans/#{plan_code}")
           .to_return(body: error_response, status: 422)
       end
 
       it 'raises an error' do
-        expect { resource.destroy(factory_plan.code) }.to raise_error Lago::Api::HttpError
+        expect { resource.destroy(plan_code) }.to raise_error Lago::Api::HttpError
       end
     end
   end
 
   describe '#get_all' do
-    let(:response) do
-      {
-        'plans' => [
-          {
-            'lago_id' => 'this-is-lago-id',
-            'name' => factory_plan.name,
-            'invoice_display_name' => factory_plan.invoice_display_name,
-            'created_at' => '2022-04-29T08:59:51Z',
-            'code' => factory_plan.code,
-            'interval' => factory_plan.amount_cents,
-            'description' => factory_plan.amount_currency,
-            'amount_cents' => factory_plan.expiration,
-            'amount_currency' => factory_plan.expiration_duration,
-            'trial_period' => 2,
-            'pay_in_advance' => false,
-            'bill_charges_monthly' => false,
-            'active_subscriptions_count' => 0,
-            'draft_invoices_count' => 0,
-            'charges' => [
-              {
-                'lago_id' => 'id',
-                'lago_billable_metric_id' => factory_plan.charges.first[:lago_billable_metric_id],
-                'billable_metric_code' => 'bm_code',
-                'created_at' => '2022-04-29T08:59:51Z',
-                'charge_model' => factory_plan.charges.first[:charge_model],
-                'invoice_display_name' => factory_plan.charges.first[:invoice_display_name],
-                'pay_in_advance' => false,
-                'min_amount_cents' => 0,
-                'properties' => factory_plan.charges.first[:properties],
-                'group_properties' => [],
-              }
-            ]
-          }
-        ],
-        'meta': {
-          'current_page' => 1,
-          'next_page' => 2,
-          'prev_page' => nil,
-          'total_pages' => 7,
-          'total_count' => 63,
-        }
-      }.to_json
-    end
+    let(:plans_response) { load_fixture('plans') }
 
     context 'when there is no options' do
       before do
         stub_request(:get, 'https://api.getlago.com/api/v1/plans')
-          .to_return(body: response, status: 200)
+          .to_return(body: plans_response, status: 200)
       end
 
       it 'returns plans on the first page' do
         response = resource.get_all
 
-        expect(response['plans'].first['lago_id']).to eq('this-is-lago-id')
-        expect(response['plans'].first['name']).to eq(factory_plan.name)
-        expect(response['plans'].first['invoice_display_name']).to eq(factory_plan.invoice_display_name)
-        expect(response['plans'].first['charges'].first['invoice_display_name']).to eq(factory_plan.charges.first[:invoice_display_name])
+        expect(response['plans'].first['lago_id']).to eq(plan_id)
+        expect(response['plans'].first['name']).to eq(plan_name)
+        expect(response['plans'].first['invoice_display_name']).to eq(plan_dsplay_name)
+        expect(response['plans'].first['charges'].first['invoice_display_name']).to eq('Charge 1')
+        expect(response['plans'].first['charges'].first['properties']['grouped_by']).to eq(['agent_name'])
         expect(response['meta']['current_page']).to eq(1)
       end
     end
@@ -244,15 +171,15 @@
     context 'when options are present' do
       before do
         stub_request(:get, 'https://api.getlago.com/api/v1/plans?per_page=2&page=1')
-          .to_return(body: response, status: 200)
+          .to_return(body: plans_response, status: 200)
       end
 
       it 'returns plans on selected page' do
         response = resource.get_all({ per_page: 2, page: 1 })
 
-        expect(response['plans'].first['lago_id']).to eq('this-is-lago-id')
-        expect(response['plans'].first['name']).to eq(factory_plan.name)
-        expect(response['plans'].first['invoice_display_name']).to eq(factory_plan.invoice_display_name)
+        expect(response['plans'].first['lago_id']).to eq(plan_id)
+        expect(response['plans'].first['name']).to eq(plan_name)
+        expect(response['plans'].first['invoice_display_name']).to eq(plan_dsplay_name)
         expect(response['meta']['current_page']).to eq(1)
       end
     end