diff --git a/.github/workflows/coverage.yaml b/.github/workflows/coverage.yaml
new file mode 100644
index 0000000..079eaf1
--- /dev/null
+++ b/.github/workflows/coverage.yaml
@@ -0,0 +1,24 @@
+name: Test Coverage
+
+on:
+  workflow_call:
+
+  workflow_dispatch:
+
+jobs:
+  SimpleCov:
+    runs-on: ubuntu-latest
+    steps:
+      # Only download these artifacts if they don't already exist
+      - if: ${{ hashFiles('coverage/.last_run.json') == '' }}
+        uses: actions/download-artifact@v4
+        with:
+          name: coverage-last-run
+          path: coverage/
+
+      - name: Check SimpleCov coverage
+        uses: joshmfrankel/simplecov-check-action@main
+        with:
+          minimum_suite_coverage: 97
+          minimum_file_coverage: 90
+          github_token: ${{ secrets.GITHUB_TOKEN }}
diff --git a/.github/workflows/main.yaml b/.github/workflows/main.yaml
index 016759e..47b1683 100644
--- a/.github/workflows/main.yaml
+++ b/.github/workflows/main.yaml
@@ -15,12 +15,25 @@ jobs:
           - '4.0.0'
     steps:
       - uses: actions/checkout@v4
+        name: Checkout code
+
       - name: Set up Ruby
         uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby }}
-          bundler-cache: false
+          bundler-cache: true
+
       - name: Install dependencies
         run: bundle install --jobs 4 --retry 3
-      - name: Run the default task
+
+      - name: Run the default rake task
         run: bundle exec rake
+        env:
+          COVERAGE: "true"
+
+      - name: Upload coverage
+        uses: actions/upload-artifact@v4
+        with:
+          name: coverage-last-run
+          path: coverage/
+          include-hidden-files: true
diff --git a/.github/workflows/validations.yaml b/.github/workflows/validations.yaml
index bd9ea2c..148729c 100644
--- a/.github/workflows/validations.yaml
+++ b/.github/workflows/validations.yaml
@@ -10,3 +10,8 @@ jobs:
   validate_ruby:
     name: Ruby Tests
     uses: ./.github/workflows/main.yaml
+
+  ensure_coverage:
+    needs: validate_ruby
+    name: Check SimpleCov coverage
+    uses: ./.github/workflows/coverage.yaml
diff --git a/Gemfile b/Gemfile
index 9488179..e205af3 100644
--- a/Gemfile
+++ b/Gemfile
@@ -13,3 +13,6 @@ gem 'rubocop'
 gem 'rubocop-minitest'
 gem 'rubocop-performance'
 gem 'rubocop-rake'
+gem 'shoulda-context'
+gem 'simplecov'
+gem 'simplecov-json'
diff --git a/Gemfile.lock b/Gemfile.lock
index 27f4c9e..1ee3c0c 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -29,6 +29,7 @@ GEM
     disposable (0.6.3)
       declarative (>= 0.0.9, < 1.0.0)
       representable (>= 3.1.1, < 4)
+    docile (1.4.1)
     dry-cli (1.3.0)
     dry-configurable (1.3.0)
       dry-core (~> 1.1)
@@ -135,6 +136,16 @@ GEM
     ruby-progressbar (1.13.0)
     semantic_logger (4.17.0)
       concurrent-ruby (~> 1.0)
+    shoulda-context (2.0.0)
+    simplecov (0.22.0)
+      docile (~> 1.1)
+      simplecov-html (~> 0.11)
+      simplecov_json_formatter (~> 0.1)
+    simplecov-html (0.13.2)
+    simplecov-json (0.2.3)
+      json
+      simplecov
+    simplecov_json_formatter (0.1.4)
     trailblazer (2.1.3)
       trailblazer-activity-dsl-linear (>= 1.2.3, < 1.3.0)
       trailblazer-developer (>= 0.1.0, < 0.2.0)
@@ -187,6 +198,9 @@ DEPENDENCIES
   rubocop-minitest
   rubocop-performance
   rubocop-rake
+  shoulda-context
+  simplecov
+  simplecov-json
 
 CHECKSUMS
   addressable (2.8.8) sha256=7c13b8f9536cf6364c03b9d417c19986019e28f7c00ac8132da4eb0fe393b057
@@ -197,6 +211,7 @@ CHECKSUMS
   crack (1.0.1) sha256=ff4a10390cd31d66440b7524eb1841874db86201d5b70032028553130b6d4c7e
   declarative (0.0.20) sha256=8021dd6cb17ab2b61233c56903d3f5a259c5cf43c80ff332d447d395b17d9ff9
   disposable (0.6.3) sha256=7f2a3fb251bff6cd83f25b164043d4ec3531209b51b066ed476a9df9c2d384cc
+  docile (1.4.1) sha256=96159be799bfa73cdb721b840e9802126e4e03dfc26863db73647204c727f21e
   domeapi (0.0.2)
   dry-cli (1.3.0) sha256=984a715f9d7f8d9bf87b6530acdd4321dcf747636bfeb3ea7fd1b81bc0226e84
   dry-configurable (1.3.0) sha256=882d862858567fc1210d2549d4c090f34370fc1bb7c5c1933de3fe792e18afa8
@@ -241,6 +256,11 @@ CHECKSUMS
   rubocop-rake (0.7.1) sha256=3797f2b6810c3e9df7376c26d5f44f3475eda59eb1adc38e6f62ecf027cbae4d
   ruby-progressbar (1.13.0) sha256=80fc9c47a9b640d6834e0dc7b3c94c9df37f08cb072b7761e4a71e22cff29b33
   semantic_logger (4.17.0) sha256=c54b60d8596abe2e22bd4f20648d4f6c46e4287fba357779c7932335c8d130e9
+  shoulda-context (2.0.0) sha256=7adf45342cd800f507d2a053658cb1cce2884b616b26004d39684b912ea32c34
+  simplecov (0.22.0) sha256=fe2622c7834ff23b98066bb0a854284b2729a569ac659f82621fc22ef36213a5
+  simplecov-html (0.13.2) sha256=bd0b8e54e7c2d7685927e8d6286466359b6f16b18cb0df47b508e8d73c777246
+  simplecov-json (0.2.3) sha256=c63823b5dfc95c85ff4cb94251765f08a166bdd68098f259368cbfe738e281f7
+  simplecov_json_formatter (0.1.4) sha256=529418fbe8de1713ac2b2d612aa3daa56d316975d307244399fa4838c601b428
   trailblazer (2.1.3) sha256=8adf157f552a4843de51456f7e70e28422799e5d060b265814d145774b8845b7
   trailblazer-activity (0.17.0) sha256=2166bc8b3410b808ad2bfe00efaf559533d1b9a6fb0d704cf3bdad02cd6c0b88
   trailblazer-activity-dsl-linear (1.2.6) sha256=42e4d3c9bd9469b65f9265fba74c703cf1a4117ea7f42a0a78112ebb3bab986f
diff --git a/Rakefile b/Rakefile
index fd157b8..4564da1 100644
--- a/Rakefile
+++ b/Rakefile
@@ -1,9 +1,13 @@
 # frozen_string_literal: true
 
 require 'bundler/gem_tasks'
-require 'minitest/test_task'
+require 'rake/testtask'
 
-Minitest::TestTask.create
+Rake::TestTask.new do |t|
+  t.libs << 'test'
+  t.test_files = FileList['test/**/*_test.rb']
+  t.ruby_opts = %w[-rhelper]
+end
 
 require 'rubocop/rake_task'
 
diff --git a/Readme.adoc b/Readme.adoc
index 510aa23..2077216 100644
--- a/Readme.adoc
+++ b/Readme.adoc
@@ -102,6 +102,22 @@ filter = Rubyists::Domeapi::Polymarket::TradeHistory::Filter.new(
 trades = client.polymarket.trade_history.list(filter)
 ----
 
+==== Orderbook
+
+Get orderbook history:
+
+[source,ruby]
+----
+filter = Rubyists::Domeapi::Polymarket::Orderbook::Filter.new(
+  Rubyists::Domeapi::Polymarket::Orderbook::Filter::Properties.new(
+    token_id: 'token_id',
+    start_time: 1625097600000,
+    end_time: 1625184000000
+  )
+)
+snapshots = client.polymarket.orderbook.list(filter)
+----
+
 == Development
 
 After checking out the repo, run `bin/setup` to install dependencies. Then, run `rake test` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment.
diff --git a/lib/domeapi/client.rb b/lib/domeapi/client.rb
index 314a351..2a8eeb3 100644
--- a/lib/domeapi/client.rb
+++ b/lib/domeapi/client.rb
@@ -25,7 +25,7 @@ def get(path, params: {})
       end
 
       def polymarket
-        @polymarket ||= Polymarket::Client.new(self)
+        @polymarket ||= Polymarket::Client.new(clone)
       end
 
       private
diff --git a/lib/domeapi/contract.rb b/lib/domeapi/contract.rb
index e000d1e..e7d9b87 100644
--- a/lib/domeapi/contract.rb
+++ b/lib/domeapi/contract.rb
@@ -9,6 +9,21 @@ module Domeapi
     class Contract < Reform::Form
       feature Reform::Form::Dry
 
+      # Custom class methods can be defined here
+      module ClassMethods
+        def propertize(*names)
+          # names is always an array because of the splat
+          names = names.flatten
+          const_set(:Properties, Struct.new(*custom_definitions, *names, keyword_init: true))
+          names.each { |name| property name, populator: ->(value:, **) { value || skip! } }
+        end
+      end
+
+      def self.inherited(subclass)
+        subclass.extend ClassMethods
+        super
+      end
+
       def self.custom_definitions = instance_variable_get(:@definitions)&.keys&.map(&:to_sym) || []
 
       def to_h
diff --git a/lib/domeapi/polymarket.rb b/lib/domeapi/polymarket.rb
index dd5eeee..43c3953 100644
--- a/lib/domeapi/polymarket.rb
+++ b/lib/domeapi/polymarket.rb
@@ -7,3 +7,14 @@ module Polymarket
     end
   end
 end
+
+require_relative 'polymarket/endpoint'
+require_relative 'polymarket/listable'
+require_relative 'polymarket/markets'
+require_relative 'polymarket/candlesticks'
+require_relative 'polymarket/trade_history'
+require_relative 'polymarket/orderbook'
+require_relative 'polymarket/activity'
+require_relative 'polymarket/market_price'
+require_relative 'polymarket/wallet'
+require_relative 'polymarket/wallet_profit_and_loss'
diff --git a/lib/domeapi/polymarket/activity.rb b/lib/domeapi/polymarket/activity.rb
new file mode 100644
index 0000000..92df302
--- /dev/null
+++ b/lib/domeapi/polymarket/activity.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+module Rubyists
+  module Domeapi
+    module Polymarket
+      # Activity API endpoints
+      class Activity < Endpoint
+        include Listable
+
+        polymarket_path 'activity'
+
+        # Filter for activity
+        class Filter < Contract
+          propertize(%i[user start_time end_time market_slug condition_id limit offset])
+
+          validation do
+            # :nocov:
+            params do
+              required(:user).filled(:string)
+              optional(:start_time).maybe(:integer)
+              optional(:end_time).maybe(:integer)
+              optional(:market_slug).maybe(:string)
+              optional(:condition_id).maybe(:string)
+              optional(:limit).maybe(:integer, gteq?: 1, lteq?: 1000)
+              optional(:offset).maybe(:integer, gteq?: 0)
+            end
+            # :nocov:
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/lib/domeapi/polymarket/candlesticks.rb b/lib/domeapi/polymarket/candlesticks.rb
index 2c4099a..69937ab 100644
--- a/lib/domeapi/polymarket/candlesticks.rb
+++ b/lib/domeapi/polymarket/candlesticks.rb
@@ -5,39 +5,26 @@ module Domeapi
     module Polymarket
       # Candlesticks API endpoints
       class Candlesticks < Endpoint
+        include Listable
+
+        polymarket_path 'markets/get_candlesticks'
+
         # Filter for listing candlesticks,
         # from https://docs.domeapi.io/api-reference/endpoint/get-candlesticks
         class Filter < Contract
-          Properties = Struct.new(
-            :condition_id,
-            :start_time,
-            :end_time,
-            :interval,
-            keyword_init: true
-          )
-
-          Properties.members.each { |member| property member, populator: ->(value:, **) { value || skip! } }
+          propertize(%i[condition_id start_time end_time interval])
 
           validation do
+            # :nocov:
             params do
               required(:condition_id).filled(:string)
               required(:start_time).filled(:integer)
               required(:end_time).filled(:integer)
               optional(:interval).maybe(:integer, gteq?: 1, lteq?: 1440)
             end
+            # :nocov:
           end
         end
-
-        # Get OHLC candlesticks
-        #
-        # @param filter [Filter] Filter options
-        #
-        # @return [Candlestick] The candlestick data
-        def list(filter = Filter.new(Filter::Properties.new))
-          raise ArgumentError, filter.errors.full_messages.join(', ') unless filter.valid?
-
-          client.get('markets/get_candlesticks', params: filter.to_h)
-        end
       end
     end
   end
diff --git a/lib/domeapi/polymarket/client.rb b/lib/domeapi/polymarket/client.rb
index a7ac535..2d6a58d 100644
--- a/lib/domeapi/polymarket/client.rb
+++ b/lib/domeapi/polymarket/client.rb
@@ -27,6 +27,26 @@ def candlesticks
         def trade_history
           @trade_history ||= TradeHistory.new(client)
         end
+
+        def orderbook
+          @orderbook ||= Orderbook.new(client)
+        end
+
+        def activity
+          @activity ||= Activity.new(client)
+        end
+
+        def market_price
+          @market_price ||= MarketPrice.new(client)
+        end
+
+        def wallet
+          @wallet ||= Wallet.new(client)
+        end
+
+        def wallet_profit_and_loss
+          @wallet_profit_and_loss ||= WalletProfitAndLoss.new(client)
+        end
       end
     end
   end
diff --git a/lib/domeapi/polymarket/endpoint.rb b/lib/domeapi/polymarket/endpoint.rb
index 6d09b7f..ac832b3 100644
--- a/lib/domeapi/polymarket/endpoint.rb
+++ b/lib/domeapi/polymarket/endpoint.rb
@@ -13,7 +13,7 @@ class Endpoint
         #
         # @return [void]
         def initialize(client = nil)
-          @client = client || ::Rubyists::Domeapi::Client.new
+          @client = client || Client.new
         end
       end
     end
diff --git a/lib/domeapi/polymarket/listable.rb b/lib/domeapi/polymarket/listable.rb
new file mode 100644
index 0000000..86fbab2
--- /dev/null
+++ b/lib/domeapi/polymarket/listable.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+module Rubyists
+  module Domeapi
+    module Polymarket
+      # Mixin for listable resources
+      module Listable
+        def self.included(base)
+          base.extend(ClassMethods)
+        end
+
+        # Class methods for Listable
+        module ClassMethods
+          attr_accessor :endpoint_path
+
+          # Set the endpoint path for the resource
+          #
+          # @param path [String] API endpoint path
+          #
+          # @return [String] endpoint path
+          def polymarket_path(path)
+            self.endpoint_path = path
+          end
+
+          def list(...)
+            new.list(...)
+          end
+        end
+
+        # List resources
+        #
+        # @param filter [Filter|Hash] Filter options
+        #
+        # @return [Hash|Array] resource data
+        def list(filter = self.class::Filter.new(self.class::Filter::Properties.new))
+          filter = self.class::Filter.new(self.class::Filter::Properties.new(**filter)) if filter.is_a?(Hash)
+          raise ArgumentError, filter.errors.full_messages.join(', ') unless filter.validate({})
+
+          client.get(self.class.endpoint_path, params: filter.to_h)
+        end
+      end
+    end
+  end
+end
diff --git a/lib/domeapi/polymarket/market_price.rb b/lib/domeapi/polymarket/market_price.rb
new file mode 100644
index 0000000..18abe83
--- /dev/null
+++ b/lib/domeapi/polymarket/market_price.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+module Rubyists
+  module Domeapi
+    module Polymarket
+      # Market Price API endpoints
+      class MarketPrice < Endpoint
+        include Listable
+
+        polymarket_path 'markets/get_market_price'
+
+        # Filter for market price
+        class Filter < Contract
+          propertize(%i[token_id at_time])
+
+          validation do
+            # :nocov:
+            params do
+              required(:token_id).filled(:string)
+              optional(:at_time).maybe(:integer)
+            end
+            # :nocov:
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/lib/domeapi/polymarket/markets.rb b/lib/domeapi/polymarket/markets.rb
index 2ff9ffd..d0b88c0 100644
--- a/lib/domeapi/polymarket/markets.rb
+++ b/lib/domeapi/polymarket/markets.rb
@@ -4,63 +4,26 @@ module Rubyists
   module Domeapi
     module Polymarket
       # Markets API endpoints
-      class Markets
-        attr_reader :client
+      class Markets < Endpoint
+        include Listable
+
+        polymarket_path 'markets'
 
         # Filter for Polymarket markets,
         # from https://docs.domeapi.io/api-reference/endpoint/get-markets
         class Filter < Contract
-          Properties = Struct.new(
-            :market_slug,
-            :event_slug,
-            :condition_id,
-            :tags,
-            :status,
-            :min_volume,
-            :limit,
-            :offset,
-            :start_time,
-            :end_time,
-            keyword_init: true
-          )
-
-          # Define properties with custom populator to skip optional params with nil values
-          Properties.members.each do |member|
-            property member, populator: ->(value:, **) { value || skip! }
-          end
+          propertize(%i[market_slug event_slug condition_id tags status min_volume limit offset start_time end_time])
 
           validation do
+            # :nocov:
             params do
               optional(:status).maybe(:string, included_in?: %w[open closed])
               optional(:offset).maybe(:integer, gteq?: 0, lteq?: 100)
             end
+            # :nocov:
           end
         end
 
-        class << self
-          # @see #list
-          def list(...)
-            new.list(...)
-          end
-        end
-
-        # @param client [Rubyists::Domeapi::Polymarket::Client]
-        #
-        # @return [void]
-        def initialize(client = Rubyists::Domeapi::Polymarket::Client.new)
-          @client = client
-        end
-
-        # List markets
-        # @param filter [MarketFilter] Filter options
-        #
-        # @return [Array<Polymarket::Market>] list of markets
-        def list(filter = Filter.new(Filter::Properties.new))
-          raise ArgumentError, filter.errors.full_messages.join(', ') unless filter.valid?
-
-          client.get('markets', params: filter.to_h)
-        end
-
         # Fetch current or historical price for a market
         #
         # @param token_id [String]
diff --git a/lib/domeapi/polymarket/orderbook.rb b/lib/domeapi/polymarket/orderbook.rb
new file mode 100644
index 0000000..d3efa26
--- /dev/null
+++ b/lib/domeapi/polymarket/orderbook.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+module Rubyists
+  module Domeapi
+    module Polymarket
+      # Orderbook API endpoints
+      class Orderbook < Endpoint
+        include Listable
+
+        polymarket_path 'markets/get_orderbook_history'
+
+        # Filter for orderbook history
+        class Filter < Contract
+          propertize(%i[token_id start_time end_time limit offset])
+
+          validation do
+            # :nocov:
+            params do
+              required(:token_id).filled(:string)
+              required(:start_time).filled(:integer)
+              required(:end_time).filled(:integer)
+              optional(:limit).maybe(:integer, gteq?: 1, lteq?: 1000)
+              optional(:offset).maybe(:integer, gteq?: 0)
+            end
+            # :nocov:
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/lib/domeapi/polymarket/trade_history.rb b/lib/domeapi/polymarket/trade_history.rb
index e9f7d46..dbe5d30 100644
--- a/lib/domeapi/polymarket/trade_history.rb
+++ b/lib/domeapi/polymarket/trade_history.rb
@@ -4,33 +4,19 @@ module Rubyists
   module Domeapi
     module Polymarket
       # Trade History API endpoints
-      class TradeHistory
-        attr_reader :client
+      class TradeHistory < Endpoint
+        include Listable
 
-        # @param client [Rubyists::Domeapi::Polymarket::Client]
-        #
-        # @return [void]
-        def initialize(client = Rubyists::Domeapi::Polymarket::Client.new)
-          @client = client
-        end
+        polymarket_path 'markets/get_trade_history'
+
+        attr_reader :client
 
         # Filter for trade history
         class Filter < Contract
-          Properties = Struct.new(
-            :market_slug,
-            :condition_id,
-            :token_id,
-            :start_time,
-            :end_time,
-            :limit,
-            :offset,
-            :user,
-            keyword_init: true
-          )
-
-          Properties.members.each { |member| property member, populator: ->(model:, **) { model || skip! } }
+          propertize(%i[market_slug condition_id token_id start_time end_time limit offset user])
 
           validation do
+            # :nocov:
             params do
               optional(:market_slug).maybe(:string)
               optional(:condition_id).maybe(:string)
@@ -41,19 +27,9 @@ class Filter < Contract
               optional(:offset).maybe(:integer, gteq?: 0)
               optional(:user).maybe(:string)
             end
+            # :nocov:
           end
         end
-
-        # Get trade history
-        #
-        # @param filter [Filter] Filter options
-        #
-        # @return [Hash] trade history data
-        def list(filter = Filter.new(Filter::Properties.new))
-          raise ArgumentError, filter.errors.full_messages.join(', ') unless filter.validate({})
-
-          client.get('markets/get_trade_history', params: filter.to_h)
-        end
       end
     end
   end
diff --git a/lib/domeapi/polymarket/wallet.rb b/lib/domeapi/polymarket/wallet.rb
new file mode 100644
index 0000000..c0fd6b8
--- /dev/null
+++ b/lib/domeapi/polymarket/wallet.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+module Rubyists
+  module Domeapi
+    module Polymarket
+      # Wallet API endpoints
+      class Wallet < Endpoint
+        include Listable
+
+        polymarket_path 'wallet'
+
+        # Filter for wallet
+        class Filter < Contract
+          propertize(%i[eoa proxy with_metrics start_time end_time])
+
+          validation do
+            # :nocov:
+            params do
+              optional(:eoa).maybe(:string)
+              optional(:proxy).maybe(:string)
+              optional(:with_metrics).maybe(:bool)
+              optional(:start_time).maybe(:integer)
+              optional(:end_time).maybe(:integer)
+            end
+
+            rule(:eoa, :proxy) do
+              key.failure('Either eoa or proxy must be provided, but not both') if values[:eoa] && values[:proxy]
+              key.failure('Either eoa or proxy must be provided') if !values[:eoa] && !values[:proxy]
+            end
+            # :nocov:
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/lib/domeapi/polymarket/wallet_profit_and_loss.rb b/lib/domeapi/polymarket/wallet_profit_and_loss.rb
new file mode 100644
index 0000000..0fffd3d
--- /dev/null
+++ b/lib/domeapi/polymarket/wallet_profit_and_loss.rb
@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+module Rubyists
+  module Domeapi
+    module Polymarket
+      # Wallet Profit and Loss API endpoints
+      class WalletProfitAndLoss < Endpoint
+        include Listable
+
+        polymarket_path 'wallet/pnl'
+
+        # Filter for wallet pnl
+        class Filter < Contract
+          propertize(%i[wallet_address granularity start_time end_time])
+
+          validation do
+            # :nocov:
+            params do
+              required(:wallet_address).filled(:string)
+              required(:granularity).filled(:string, included_in?: %w[day week month year all])
+              optional(:start_time).maybe(:integer)
+              optional(:end_time).maybe(:integer)
+            end
+            # :nocov:
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/test/domeapi/client_test.rb b/test/domeapi/client_test.rb
new file mode 100644
index 0000000..a783e1b
--- /dev/null
+++ b/test/domeapi/client_test.rb
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+require_relative '../helper'
+
+describe Rubyists::Domeapi::Client do
+  let(:client) { Rubyists::Domeapi::Client.new }
+
+  before do
+    Rubyists::Domeapi.configure do |config|
+      config.api_key = 'test_api_key'
+    end
+  end
+
+  it 'handles API errors' do
+    stub_request(:get, 'https://api.domeapi.io/v1/error')
+      .to_return(status: 500, body: 'Internal Server Error')
+
+    error = _ { client.get('error') }.must_raise Rubyists::Domeapi::Error
+    _(error.message).must_include 'API Error: 500'
+    _(error.message).must_include 'Internal Server Error'
+  end
+
+  it 'constructs full url correctly' do
+    client.prefix = 'test'
+    # We can't easily test private methods, but we can test the effect via get
+    stub_request(:get, 'https://api.domeapi.io/v1/test/path')
+      .to_return(status: 200, body: '{}')
+
+    client.get('path')
+  end
+
+  it 'returns a polymarket client' do
+    _(client.polymarket).must_be_instance_of Rubyists::Domeapi::Polymarket::Client
+  end
+end
diff --git a/test/domeapi/contract_test.rb b/test/domeapi/contract_test.rb
new file mode 100644
index 0000000..cc05e8d
--- /dev/null
+++ b/test/domeapi/contract_test.rb
@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+require_relative '../helper'
+
+describe Rubyists::Domeapi::Contract do
+  describe '.propertize' do
+    class TestContract < Rubyists::Domeapi::Contract # rubocop:disable Lint/ConstantDefinitionInBlock
+      propertize %i[foo bar]
+    end
+
+    it 'defines a Properties struct' do
+      assert TestContract.const_defined?(:Properties)
+      _(TestContract::Properties.members).must_equal %i[foo bar]
+    end
+
+    it 'accepts splat arguments' do
+      klass = Class.new(Rubyists::Domeapi::Contract) do
+        propertize :foo, :bar
+      end
+
+      _(klass::Properties.members).must_equal %i[foo bar]
+    end
+
+    it 'uses keyword_init for the struct' do
+      _(TestContract::Properties.new(foo: 'bar').foo).must_equal 'bar'
+      assert_raises(ArgumentError) { TestContract::Properties.new('bar', 'baz') }
+    end
+
+    it 'defines properties on the contract' do
+      contract = TestContract.new(TestContract::Properties.new(foo: 'baz'))
+
+      _(contract.foo).must_equal 'baz'
+    end
+
+    it 'skips nil values' do
+      contract = TestContract.new(TestContract::Properties.new(foo: 'baz', bar: nil))
+      contract.validate({})
+
+      _(contract.to_h).must_equal({ 'foo' => 'baz' })
+    end
+
+    it 'includes existing definitions' do
+      klass = Class.new(Rubyists::Domeapi::Contract) do
+        property :existing
+        propertize :new_prop
+      end
+
+      _(klass::Properties.members).must_include :existing
+      _(klass::Properties.members).must_include :new_prop
+    end
+  end
+end
diff --git a/test/domeapi/polymarket/activity_test.rb b/test/domeapi/polymarket/activity_test.rb
new file mode 100644
index 0000000..89cef43
--- /dev/null
+++ b/test/domeapi/polymarket/activity_test.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+require_relative '../../helper'
+
+describe Rubyists::Domeapi::Client do
+  let(:client) { Rubyists::Domeapi::Client.new }
+  let(:activity) { client.polymarket.activity }
+
+  before do
+    Rubyists::Domeapi.configure do |config|
+      config.api_key = 'test_api_key'
+    end
+  end
+
+  describe 'Polymarket Activity' do
+    it 'gets activity' do
+      stub_request(:get, 'https://api.domeapi.io/v1/polymarket/activity')
+        .with(query: { user: '0x123' })
+        .to_return(status: 200, body: '{"activities": []}')
+
+      response = activity.list(user: '0x123')
+
+      _(response).must_equal({ activities: [] })
+    end
+
+    it 'validates required parameters' do
+      error = _ { activity.list({}) }.must_raise ArgumentError
+      _(error.message).must_include 'User must be filled'
+    end
+  end
+end
diff --git a/test/domeapi/polymarket/candlesticks_test.rb b/test/domeapi/polymarket/candlesticks_test.rb
index 5feba32..58dd532 100644
--- a/test/domeapi/polymarket/candlesticks_test.rb
+++ b/test/domeapi/polymarket/candlesticks_test.rb
@@ -48,6 +48,16 @@
       _(response).must_equal({ candlesticks: [] })
     end
 
+    it 'gets candlesticks with hash filter' do
+      stub_request(:get, 'https://api.domeapi.io/v1/polymarket/markets/get_candlesticks')
+        .with(query: { condition_id: 'abc', start_time: '100', end_time: '200' })
+        .to_return(status: 200, body: '{"candlesticks": []}')
+
+      response = candlesticks.list(condition_id: 'abc', start_time: 100, end_time: 200)
+
+      _(response).must_equal({ candlesticks: [] })
+    end
+
     it 'validates required parameters' do
       filter = Rubyists::Domeapi::Polymarket::Candlesticks::Filter.new(
         Rubyists::Domeapi::Polymarket::Candlesticks::Filter::Properties.new
diff --git a/test/domeapi/polymarket/client_test.rb b/test/domeapi/polymarket/client_test.rb
new file mode 100644
index 0000000..7558363
--- /dev/null
+++ b/test/domeapi/polymarket/client_test.rb
@@ -0,0 +1,83 @@
+# frozen_string_literal: true
+
+require_relative '../../helper'
+
+describe Rubyists::Domeapi::Polymarket::Client do
+  it 'initializes with default client' do
+    client = Rubyists::Domeapi::Polymarket::Client.new
+
+    _(client.client).must_be_instance_of Rubyists::Domeapi::Client
+  end
+
+  it 'sets prefix on initialization' do
+    client = Rubyists::Domeapi::Client.new
+    Rubyists::Domeapi::Polymarket::Client.new(client)
+
+    _(client.prefix).must_equal 'polymarket'
+  end
+
+  it 'delegates get to the client' do
+    mock_client = Object.new
+    class << mock_client
+      attr_accessor :prefix
+
+      def get(path, params: {})
+        { path: path, params: params }
+      end
+    end
+
+    client = Rubyists::Domeapi::Polymarket::Client.new(mock_client)
+    result = client.get('path')
+
+    _(mock_client.prefix).must_equal 'polymarket'
+    _(result).must_equal({ path: 'path', params: {} })
+  end
+
+  it 'initializes markets endpoint' do
+    client = Rubyists::Domeapi::Polymarket::Client.new
+
+    _(client.markets).must_be_instance_of Rubyists::Domeapi::Polymarket::Markets
+  end
+
+  it 'initializes candlesticks endpoint' do
+    client = Rubyists::Domeapi::Polymarket::Client.new
+
+    _(client.candlesticks).must_be_instance_of Rubyists::Domeapi::Polymarket::Candlesticks
+  end
+
+  it 'initializes trade_history endpoint' do
+    client = Rubyists::Domeapi::Polymarket::Client.new
+
+    _(client.trade_history).must_be_instance_of Rubyists::Domeapi::Polymarket::TradeHistory
+  end
+
+  it 'initializes orderbook endpoint' do
+    client = Rubyists::Domeapi::Polymarket::Client.new
+
+    _(client.orderbook).must_be_instance_of Rubyists::Domeapi::Polymarket::Orderbook
+  end
+
+  it 'initializes activity endpoint' do
+    client = Rubyists::Domeapi::Polymarket::Client.new
+
+    _(client.activity).must_be_instance_of Rubyists::Domeapi::Polymarket::Activity
+  end
+
+  it 'initializes market_price endpoint' do
+    client = Rubyists::Domeapi::Polymarket::Client.new
+
+    _(client.market_price).must_be_instance_of Rubyists::Domeapi::Polymarket::MarketPrice
+  end
+
+  it 'initializes wallet endpoint' do
+    client = Rubyists::Domeapi::Polymarket::Client.new
+
+    _(client.wallet).must_be_instance_of Rubyists::Domeapi::Polymarket::Wallet
+  end
+
+  it 'initializes wallet_profit_and_loss endpoint' do
+    client = Rubyists::Domeapi::Polymarket::Client.new
+
+    _(client.wallet_profit_and_loss).must_be_instance_of Rubyists::Domeapi::Polymarket::WalletProfitAndLoss
+  end
+end
diff --git a/test/domeapi/polymarket/endpoint_test.rb b/test/domeapi/polymarket/endpoint_test.rb
new file mode 100644
index 0000000..dbe6112
--- /dev/null
+++ b/test/domeapi/polymarket/endpoint_test.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+require_relative '../../helper'
+
+describe Rubyists::Domeapi::Polymarket::Endpoint do
+  it 'initializes with default client' do
+    endpoint = Rubyists::Domeapi::Polymarket::Endpoint.new
+
+    _(endpoint.client).must_be_instance_of Rubyists::Domeapi::Polymarket::Client
+  end
+
+  it 'initializes with provided client' do
+    client = Object.new
+    endpoint = Rubyists::Domeapi::Polymarket::Endpoint.new(client)
+
+    _(endpoint.client).must_equal client
+  end
+end
diff --git a/test/domeapi/polymarket/listable_test.rb b/test/domeapi/polymarket/listable_test.rb
new file mode 100644
index 0000000..b914c29
--- /dev/null
+++ b/test/domeapi/polymarket/listable_test.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+require_relative '../../helper'
+
+describe Rubyists::Domeapi::Polymarket::Listable do
+  # Test using Markets as it includes Listable
+  describe 'Class methods' do
+    it 'delegates list to instance' do
+      stub_request(:get, 'https://api.domeapi.io/v1/polymarket/markets')
+        .to_return(status: 200, body: '[]')
+
+      response = Rubyists::Domeapi::Polymarket::Markets.list
+
+      _(response).must_equal []
+    end
+  end
+end
diff --git a/test/domeapi/polymarket/market_price_test.rb b/test/domeapi/polymarket/market_price_test.rb
new file mode 100644
index 0000000..9e4414e
--- /dev/null
+++ b/test/domeapi/polymarket/market_price_test.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+require_relative '../../helper'
+
+describe Rubyists::Domeapi::Client do
+  let(:client) { Rubyists::Domeapi::Client.new }
+  let(:market_price) { client.polymarket.market_price }
+
+  before do
+    Rubyists::Domeapi.configure do |config|
+      config.api_key = 'test_api_key'
+    end
+  end
+
+  describe 'Polymarket Market Price' do
+    it 'gets market price' do
+      stub_request(:get, 'https://api.domeapi.io/v1/polymarket/markets/get_market_price')
+        .with(query: { token_id: '123' })
+        .to_return(status: 200, body: '{"price": 0.5}')
+
+      response = market_price.list(token_id: '123')
+
+      _(response).must_equal({ price: 0.5 })
+    end
+
+    it 'validates required parameters' do
+      error = _ { market_price.list({}) }.must_raise ArgumentError
+      _(error.message).must_include 'Token Id must be filled'
+    end
+  end
+end
diff --git a/test/domeapi/polymarket/markets_test.rb b/test/domeapi/polymarket/markets_test.rb
index 3c0c2f4..e332ee9 100644
--- a/test/domeapi/polymarket/markets_test.rb
+++ b/test/domeapi/polymarket/markets_test.rb
@@ -29,6 +29,16 @@
       _(response).must_equal({ price: 0.5 })
     end
 
+    it 'gets market price with at_time' do
+      stub_request(:get, 'https://api.domeapi.io/v1/polymarket/markets/get_market_price')
+        .with(query: { token_id: '123', at_time: '1625097600' })
+        .to_return(status: 200, body: '{"price": 0.4}')
+
+      response = markets.price(token_id: '123', at_time: 1_625_097_600)
+
+      _(response).must_equal({ price: 0.4 })
+    end
+
     it 'lists markets' do
       stub_request(:get, 'https://api.domeapi.io/v1/polymarket/markets')
         .with(query: { limit: '10', offset: '0' })
@@ -50,5 +60,21 @@
 
       _(response).must_equal([{ id: 'market1' }])
     end
+
+    it 'lists markets with hash filter' do
+      stub_request(:get, 'https://api.domeapi.io/v1/polymarket/markets')
+        .with(query: { tags: 'nfl' })
+        .to_return(status: 200, body: '[{"id": "market1"}]')
+
+      response = markets.list(tags: 'nfl')
+
+      _(response).must_equal([{ id: 'market1' }])
+    end
+
+    it 'initializes with default client' do
+      markets = Rubyists::Domeapi::Polymarket::Markets.new
+
+      _(markets.client).must_be_instance_of Rubyists::Domeapi::Polymarket::Client
+    end
   end
 end
diff --git a/test/domeapi/polymarket/orderbook_test.rb b/test/domeapi/polymarket/orderbook_test.rb
new file mode 100644
index 0000000..953d96c
--- /dev/null
+++ b/test/domeapi/polymarket/orderbook_test.rb
@@ -0,0 +1,58 @@
+# frozen_string_literal: true
+
+require_relative '../../helper'
+
+describe Rubyists::Domeapi::Client do
+  let(:client) { Rubyists::Domeapi::Client.new }
+  let(:orderbook) { client.polymarket.orderbook }
+
+  before do
+    Rubyists::Domeapi.configure do |config|
+      config.api_key = 'test_api_key'
+    end
+  end
+
+  describe 'Polymarket Orderbook' do
+    it 'gets orderbook history' do
+      stub_request(:get, 'https://api.domeapi.io/v1/polymarket/markets/get_orderbook_history')
+        .with(query: { token_id: '123', start_time: '1000', end_time: '2000' })
+        .to_return(status: 200, body: '{"snapshots": []}')
+
+      filter = Rubyists::Domeapi::Polymarket::Orderbook::Filter.new(
+        Rubyists::Domeapi::Polymarket::Orderbook::Filter::Properties.new(
+          token_id: '123',
+          start_time: 1000,
+          end_time: 2000
+        )
+      )
+      response = orderbook.list(filter)
+
+      _(response).must_equal({ snapshots: [] })
+    end
+
+    it 'validates required parameters' do
+      filter = Rubyists::Domeapi::Polymarket::Orderbook::Filter.new(
+        Rubyists::Domeapi::Polymarket::Orderbook::Filter::Properties.new
+      )
+
+      error = _ { orderbook.list(filter) }.must_raise ArgumentError
+      _(error.message).must_include 'Token Id must be filled'
+      _(error.message).must_include 'Start Time must be filled'
+      _(error.message).must_include 'End Time must be filled'
+    end
+
+    it 'validates limit range' do
+      filter = Rubyists::Domeapi::Polymarket::Orderbook::Filter.new(
+        Rubyists::Domeapi::Polymarket::Orderbook::Filter::Properties.new(
+          token_id: '123',
+          start_time: 1000,
+          end_time: 2000,
+          limit: 1001
+        )
+      )
+
+      error = _ { orderbook.list(filter) }.must_raise ArgumentError
+      _(error.message).must_include 'Limit must be less than or equal to 1000'
+    end
+  end
+end
diff --git a/test/domeapi/polymarket/trade_history_test.rb b/test/domeapi/polymarket/trade_history_test.rb
index d210086..fe25220 100644
--- a/test/domeapi/polymarket/trade_history_test.rb
+++ b/test/domeapi/polymarket/trade_history_test.rb
@@ -29,6 +29,16 @@
       _(response).must_equal({ trades: [] })
     end
 
+    it 'gets trade history with hash filter' do
+      stub_request(:get, 'https://api.domeapi.io/v1/polymarket/markets/get_trade_history')
+        .with(query: { market_slug: 'slug', limit: '10' })
+        .to_return(status: 200, body: '{"trades": []}')
+
+      response = trade_history.list(market_slug: 'slug', limit: 10)
+
+      _(response).must_equal({ trades: [] })
+    end
+
     it 'validates limit range' do
       filter = Rubyists::Domeapi::Polymarket::TradeHistory::Filter.new(
         Rubyists::Domeapi::Polymarket::TradeHistory::Filter::Properties.new(limit: 1001)
diff --git a/test/domeapi/polymarket/wallet_profit_and_loss_test.rb b/test/domeapi/polymarket/wallet_profit_and_loss_test.rb
new file mode 100644
index 0000000..e0f7bbd
--- /dev/null
+++ b/test/domeapi/polymarket/wallet_profit_and_loss_test.rb
@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+require_relative '../../helper'
+
+describe Rubyists::Domeapi::Client do
+  let(:client) { Rubyists::Domeapi::Client.new }
+  let(:wallet_pnl) { client.polymarket.wallet_profit_and_loss }
+
+  before do
+    Rubyists::Domeapi.configure do |config|
+      config.api_key = 'test_api_key'
+    end
+  end
+
+  describe 'Polymarket Wallet Profit and Loss' do
+    it 'gets wallet pnl' do
+      stub_request(:get, 'https://api.domeapi.io/v1/polymarket/wallet/pnl')
+        .with(query: { wallet_address: '0x123', granularity: 'day' })
+        .to_return(status: 200, body: '{"pnl_over_time": []}')
+
+      response = wallet_pnl.list(wallet_address: '0x123', granularity: 'day')
+
+      _(response).must_equal({ pnl_over_time: [] })
+    end
+
+    it 'validates required parameters' do
+      error = _ { wallet_pnl.list({}) }.must_raise ArgumentError
+      _(error.message).must_include 'Wallet Address must be filled'
+      _(error.message).must_include 'Granularity must be filled'
+    end
+
+    it 'validates granularity' do
+      error = _ { wallet_pnl.list(wallet_address: '0x123', granularity: 'invalid') }.must_raise ArgumentError
+      _(error.message).must_include 'Granularity must be one of: day, week, month, year, all'
+    end
+  end
+end
diff --git a/test/domeapi/polymarket/wallet_test.rb b/test/domeapi/polymarket/wallet_test.rb
new file mode 100644
index 0000000..e0bd348
--- /dev/null
+++ b/test/domeapi/polymarket/wallet_test.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+require_relative '../../helper'
+
+describe Rubyists::Domeapi::Client do
+  let(:client) { Rubyists::Domeapi::Client.new }
+  let(:wallet) { client.polymarket.wallet }
+
+  before do
+    Rubyists::Domeapi.configure do |config|
+      config.api_key = 'test_api_key'
+    end
+  end
+
+  describe 'Polymarket Wallet' do
+    it 'gets wallet with eoa' do
+      stub_request(:get, 'https://api.domeapi.io/v1/polymarket/wallet')
+        .with(query: { eoa: '0x123' })
+        .to_return(status: 200, body: '{"eoa": "0x123"}')
+
+      response = wallet.list(eoa: '0x123')
+
+      _(response).must_equal({ eoa: '0x123' })
+    end
+
+    it 'gets wallet with proxy' do
+      stub_request(:get, 'https://api.domeapi.io/v1/polymarket/wallet')
+        .with(query: { proxy: '0x456' })
+        .to_return(status: 200, body: '{"proxy": "0x456"}')
+
+      response = wallet.list(proxy: '0x456')
+
+      _(response).must_equal({ proxy: '0x456' })
+    end
+
+    it 'validates either eoa or proxy' do
+      error = _ { wallet.list({}) }.must_raise ArgumentError
+      _(error.message).must_include 'Either eoa or proxy must be provided'
+
+      error = _ { wallet.list(eoa: '0x123', proxy: '0x456') }.must_raise ArgumentError
+      _(error.message).must_include 'Either eoa or proxy must be provided, but not both'
+    end
+  end
+end
diff --git a/test/domeapi_test.rb b/test/domeapi_test.rb
index 93e3cea..c8e443e 100644
--- a/test/domeapi_test.rb
+++ b/test/domeapi_test.rb
@@ -11,6 +11,10 @@ class DomeapiTest < Minitest::Spec
         refute_nil subject::VERSION
       end
 
+      it 'returns a default client' do
+        _(subject.client).must_be_instance_of Rubyists::Domeapi::Client
+      end
+
       describe 'VERSION' do
         subject { ::Rubyists::Domeapi::VERSION }
 
diff --git a/test/helper.rb b/test/helper.rb
index 872d038..a5dea57 100644
--- a/test/helper.rb
+++ b/test/helper.rb
@@ -1,8 +1,26 @@
 # frozen_string_literal: true
 
+if ENV['COVERAGE']
+  require 'simplecov'
+  require 'simplecov-json'
+  SimpleCov.formatters = SimpleCov::Formatter::MultiFormatter.new(
+    [
+      SimpleCov::Formatter::HTMLFormatter,
+      SimpleCov::Formatter::JSONFormatter
+    ]
+  )
+  SimpleCov.start do
+    enable_coverage :branch
+    add_filter '/test/'
+    add_filter '/vendor/'
+  end
+end
+
 require_relative '../lib/domeapi'
 
 require 'minitest/autorun'
+require 'minitest/spec'
+require 'shoulda/context'
 require 'webmock/minitest'
 require 'httpx'
 require 'httpx/adapters/webmock'