diff --git a/.credo.exs b/.credo.exs
new file mode 100644
index 0000000..8a524c0
--- /dev/null
+++ b/.credo.exs
@@ -0,0 +1,219 @@
+# This file contains the configuration for Credo and you are probably reading
+# this after creating it with `mix credo.gen.config`.
+#
+# If you find anything wrong or unclear in this file, please report an
+# issue on GitHub: https://github.com/rrrene/credo/issues
+#
+%{
+  #
+  # You can have as many configs as you like in the `configs:` field.
+  configs: [
+    %{
+      #
+      # Run any config using `mix credo -C <name>`. If no config name is given
+      # "default" is used.
+      #
+      name: "default",
+      #
+      # These are the files included in the analysis:
+      files: %{
+        #
+        # You can give explicit globs or simply directories.
+        # In the latter case `**/*.{ex,exs}` will be used.
+        #
+        included: [
+          "lib/",
+          "src/",
+          "test/",
+          "web/",
+          "apps/*/lib/",
+          "apps/*/src/",
+          "apps/*/test/",
+          "apps/*/web/"
+        ],
+        excluded: [~r"/_build/", ~r"/deps/", ~r"/node_modules/"]
+      },
+      #
+      # Load and configure plugins here:
+      #
+      plugins: [],
+      #
+      # If you create your own checks, you must specify the source files for
+      # them here, so they can be loaded by Credo before running the analysis.
+      #
+      requires: [],
+      #
+      # If you want to enforce a style guide and need a more traditional linting
+      # experience, you can change `strict` to `true` below:
+      #
+      strict: false,
+      #
+      # To modify the timeout for parsing files, change this value:
+      #
+      parse_timeout: 5000,
+      #
+      # If you want to use uncolored output by default, you can change `color`
+      # to `false` below:
+      #
+      color: true,
+      #
+      # You can customize the parameters of any check by adding a second element
+      # to the tuple.
+      #
+      # To disable a check put `false` as second element:
+      #
+      #     {Credo.Check.Design.DuplicatedCode, false}
+      #
+      checks: %{
+        enabled: [
+          #
+          ## Consistency Checks
+          #
+          {Credo.Check.Consistency.ExceptionNames, []},
+          {Credo.Check.Consistency.LineEndings, []},
+          {Credo.Check.Consistency.ParameterPatternMatching, []},
+          {Credo.Check.Consistency.SpaceAroundOperators, []},
+          {Credo.Check.Consistency.SpaceInParentheses, []},
+          {Credo.Check.Consistency.TabsOrSpaces, []},
+
+          #
+          ## Design Checks
+          #
+          # You can customize the priority of any check
+          # Priority values are: `low, normal, high, higher`
+          #
+          {Credo.Check.Design.AliasUsage, false},
+          {Credo.Check.Design.TagFIXME, []},
+          # You can also customize the exit_status of each check.
+          # If you don't want TODO comments to cause `mix credo` to fail, just
+          # set this value to 0 (zero).
+          #
+          {Credo.Check.Design.TagTODO, [exit_status: 2]},
+
+          #
+          ## Readability Checks
+          #
+          {Credo.Check.Readability.AliasOrder, []},
+          {Credo.Check.Readability.FunctionNames, []},
+          {Credo.Check.Readability.LargeNumbers, [only_greater_than: 99_999]},
+          {Credo.Check.Readability.MaxLineLength, [priority: :low, max_length: 120]},
+          {Credo.Check.Readability.ModuleAttributeNames, []},
+          {Credo.Check.Readability.ModuleDoc, false},
+          {Credo.Check.Readability.ModuleNames, []},
+          {Credo.Check.Readability.ParenthesesInCondition, []},
+          {Credo.Check.Readability.ParenthesesOnZeroArityDefs, []},
+          {Credo.Check.Readability.PipeIntoAnonymousFunctions, []},
+          {Credo.Check.Readability.PredicateFunctionNames, false},
+          {Credo.Check.Readability.PreferImplicitTry, []},
+          {Credo.Check.Readability.RedundantBlankLines, []},
+          {Credo.Check.Readability.Semicolons, []},
+          {Credo.Check.Readability.SpaceAfterCommas, []},
+          {Credo.Check.Readability.StringSigils, []},
+          {Credo.Check.Readability.TrailingBlankLine, []},
+          {Credo.Check.Readability.TrailingWhiteSpace, []},
+          {Credo.Check.Readability.UnnecessaryAliasExpansion, []},
+          {Credo.Check.Readability.VariableNames, []},
+          {Credo.Check.Readability.WithSingleClause, []},
+
+          #
+          ## Refactoring Opportunities
+          #
+          {Credo.Check.Refactor.Apply, []},
+          {Credo.Check.Refactor.CondStatements, []},
+          {Credo.Check.Refactor.CyclomaticComplexity, [max_complexity: 12]},
+          {Credo.Check.Refactor.FilterCount, []},
+          {Credo.Check.Refactor.FilterFilter, []},
+          {Credo.Check.Refactor.FunctionArity, []},
+          {Credo.Check.Refactor.LongQuoteBlocks, []},
+          {Credo.Check.Refactor.MapJoin, []},
+          {Credo.Check.Refactor.MatchInCondition, []},
+          {Credo.Check.Refactor.NegatedConditionsInUnless, []},
+          {Credo.Check.Refactor.NegatedConditionsWithElse, []},
+          {Credo.Check.Refactor.Nesting, [max_nesting: 3]},
+          {Credo.Check.Refactor.RedundantWithClauseResult, []},
+          {Credo.Check.Refactor.RejectReject, []},
+          {Credo.Check.Refactor.UnlessWithElse, []},
+          {Credo.Check.Refactor.WithClauses, []},
+
+          #
+          ## Warnings
+          #
+          {Credo.Check.Warning.ApplicationConfigInModuleAttribute, []},
+          {Credo.Check.Warning.BoolOperationOnSameValues, []},
+          {Credo.Check.Warning.Dbg, []},
+          {Credo.Check.Warning.ExpensiveEmptyEnumCheck, []},
+          {Credo.Check.Warning.IExPry, []},
+          {Credo.Check.Warning.IoInspect, []},
+          {Credo.Check.Warning.MissedMetadataKeyInLoggerConfig, []},
+          {Credo.Check.Warning.OperationOnSameValues, []},
+          {Credo.Check.Warning.OperationWithConstantResult, []},
+          {Credo.Check.Warning.RaiseInsideRescue, []},
+          {Credo.Check.Warning.SpecWithStruct, []},
+          {Credo.Check.Warning.StructFieldAmount, []},
+          {Credo.Check.Warning.UnsafeExec, []},
+          {Credo.Check.Warning.UnusedEnumOperation, []},
+          {Credo.Check.Warning.UnusedFileOperation, []},
+          {Credo.Check.Warning.UnusedKeywordOperation, []},
+          {Credo.Check.Warning.UnusedListOperation, []},
+          {Credo.Check.Warning.UnusedMapOperation, []},
+          {Credo.Check.Warning.UnusedPathOperation, []},
+          {Credo.Check.Warning.UnusedRegexOperation, []},
+          {Credo.Check.Warning.UnusedStringOperation, []},
+          {Credo.Check.Warning.UnusedTupleOperation, []},
+          {Credo.Check.Warning.WrongTestFileExtension, []}
+        ],
+        disabled: [
+          #
+          # Checks scheduled for next check update (opt-in for now)
+          {Credo.Check.Refactor.UtcNowTruncate, []},
+
+          #
+          # Controversial and experimental checks (opt-in, just move the check to `:enabled`
+          #   and be sure to use `mix credo --strict` to see low priority checks)
+          #
+          {Credo.Check.Consistency.MultiAliasImportRequireUse, []},
+          {Credo.Check.Consistency.UnusedVariableNames, []},
+          {Credo.Check.Design.DuplicatedCode, []},
+          {Credo.Check.Design.SkipTestWithoutComment, []},
+          {Credo.Check.Readability.AliasAs, []},
+          {Credo.Check.Readability.BlockPipe, []},
+          {Credo.Check.Readability.ImplTrue, []},
+          {Credo.Check.Readability.MultiAlias, []},
+          {Credo.Check.Readability.NestedFunctionCalls, []},
+          {Credo.Check.Readability.OneArityFunctionInPipe, []},
+          {Credo.Check.Readability.OnePipePerLine, []},
+          {Credo.Check.Readability.SeparateAliasRequire, []},
+          {Credo.Check.Readability.SingleFunctionToBlockPipe, []},
+          {Credo.Check.Readability.SinglePipe, []},
+          {Credo.Check.Readability.Specs, []},
+          {Credo.Check.Readability.StrictModuleLayout, []},
+          {Credo.Check.Readability.WithCustomTaggedTuple, []},
+          {Credo.Check.Refactor.ABCSize, []},
+          {Credo.Check.Refactor.AppendSingleItem, []},
+          {Credo.Check.Refactor.DoubleBooleanNegation, []},
+          {Credo.Check.Refactor.FilterReject, []},
+          {Credo.Check.Refactor.IoPuts, []},
+          {Credo.Check.Refactor.MapMap, []},
+          {Credo.Check.Refactor.ModuleDependencies, []},
+          {Credo.Check.Refactor.NegatedIsNil, []},
+          {Credo.Check.Refactor.PassAsyncInTestCases, []},
+          {Credo.Check.Refactor.PipeChainStart, []},
+          {Credo.Check.Refactor.RejectFilter, []},
+          {Credo.Check.Refactor.VariableRebinding, []},
+          {Credo.Check.Warning.LazyLogging, []},
+          {Credo.Check.Warning.LeakyEnvironment, []},
+          {Credo.Check.Warning.MapGetUnsafePass, []},
+          {Credo.Check.Warning.MixEnv, []},
+          {Credo.Check.Warning.UnsafeToAtom, []}
+          # {Credo.Check.Warning.UnusedOperation, [{MyMagicModule, [:fun1, :fun2]}]}
+
+          # {Credo.Check.Refactor.MapInto, []},
+
+          #
+          # Custom checks can be created using `mix credo.gen.check`.
+          #
+        ]
+      }
+    }
+  ]
+}
diff --git a/.dialyzer_ignore.exs b/.dialyzer_ignore.exs
new file mode 100644
index 0000000..6d301fb
--- /dev/null
+++ b/.dialyzer_ignore.exs
@@ -0,0 +1,30 @@
+[
+  # Mix.Task callbacks and functions not in dialyzer PLT (dev-only modules)
+  {"lib/mix/tasks/generate_mockups.ex", :callback_info_missing},
+  {"lib/mix/tasks/generate_mockups.ex", :unknown_function},
+  {"lib/mix/tasks/optimize_images.ex", :callback_info_missing},
+  {"lib/mix/tasks/optimize_images.ex", :unknown_function},
+  {"lib/mix/tasks/register_webhooks.ex", :callback_info_missing},
+  {"lib/mix/tasks/register_webhooks.ex", :unknown_function},
+  {"lib/mix/tasks/simpleshop/download_images.ex", :callback_info_missing},
+  {"lib/mix/tasks/simpleshop/download_images.ex", :unknown_function},
+
+  # Stripe library type specs cause false positives
+  {"lib/simpleshop_theme/stripe/setup.ex", :pattern_match_cov},
+  {"lib/simpleshop_theme/stripe/setup.ex", :pattern_match},
+  {"lib/simpleshop_theme/stripe/setup.ex", :no_return},
+  {"lib/simpleshop_theme/stripe/setup.ex", :call},
+  {"lib/simpleshop_theme_web/controllers/checkout_controller.ex", :call},
+  {"lib/simpleshop_theme_web/controllers/checkout_controller.ex", :pattern_match_cov},
+  {"lib/simpleshop_theme_web/controllers/checkout_controller.ex", :no_return},
+
+  # Environment-dependent: localhost?() is always true in dev
+  {"lib/simpleshop_theme_web/live/admin_live/settings.ex", :pattern_match},
+
+  # Provider behaviour type not derived by dialyzer
+  {"lib/simpleshop_theme/providers/provider.ex", :unknown_type},
+
+  # ExUnit internals not in PLT (test support files)
+  {"test/support/conn_case.ex", :unknown_function},
+  {"test/support/data_case.ex", :unknown_function}
+]
diff --git a/PROGRESS.md b/PROGRESS.md
index a050130..70b4088 100644
--- a/PROGRESS.md
+++ b/PROGRESS.md
@@ -20,7 +20,7 @@
 - Transactional emails (order confirmation, shipping notification)
 - Demo content polished and ready for production
 
-**Tier 1 MVP complete.** Next up: Tier 2 — hosting & deployment.
+**Tier 1 MVP complete.** CI pipeline done. Next up: Tier 2 — hosting & deployment.
 
 ## Roadmap
 
@@ -35,7 +35,7 @@
 
 5. **Hosting & deployment** — Fly.io or similar deployment config. Release configuration, runtime env setup, health checks. Observability: structured logging, error tracking (Sentry or similar), basic metrics.
 6. **Litestream / SQLite replication** — Litestream for continuous SQLite backup to S3-compatible storage. Point-in-time recovery. Simple sidecar process, no code changes needed, works with vanilla SQLite. For the hosted platform (Tier 5), evaluate [Turso](https://turso.tech/) (libSQL fork of SQLite) with embedded read replicas via [ecto_libsql](https://github.com/ocean/ecto_libsql) adapter — gives multi-node reads without a separate replication daemon, but adds a dependency on the libSQL fork.
-7. **CI pipeline** — All checks implemented as mix aliases (`mix ci` wrapping `mix precommit` + credo + dialyzer). CI config is a thin wrapper that calls `mix ci` — portable across GitHub Actions, Forgejo Actions, Woodpecker, or plain SSH. No proprietary CI dependencies. Custom mix tasks for anything project-specific (e.g. `mix lighthouse`). Oban stays for runtime background jobs, not CI.
+7. ~~**CI pipeline**~~ — ✅ Complete. `mix ci` alias: compile --warning-as-errors, deps.unlock --unused, format --check-formatted, credo, dialyzer, test. Credo configured with sensible defaults. Dialyzer with ignore file for false positives (Stripe types, Mix tasks, ExUnit internals). 612 tests, 0 failures.
 8. **PageSpeed in CI** — Lighthouse CI to catch regressions. Fail the build if score drops below threshold. Protects the current 100% score.
 9. **End-to-end tests** — Wallaby or similar for browser-based tests of critical flows: browse → add to cart → checkout → order confirmation. Covers the full happy path plus key error cases.
 
@@ -219,6 +219,16 @@ All shop pages now have LiveView integration tests (612 total):
 - **Collection page** (16 tests, pre-existing) — category filtering, sorting, URL params
 - **Content pages** (10 tests, pre-existing) — about, delivery, privacy, terms
 
+### CI Pipeline
+**Status:** Complete
+
+- `mix ci` alias: compile --warning-as-errors → deps.unlock --unused → format --check-formatted → credo → dialyzer → test
+- `mix precommit` alias: compile --warning-as-errors → deps.unlock --unused → format → test
+- Credo with tuned config (disabled AliasUsage, ModuleDoc, PredicateFunctionNames; relaxed line length, nesting, complexity)
+- Dialyzer with ignore file for known false positives (Stripe library types, Mix.Task dev-only modules, ExUnit internals)
+- All credo issues resolved (map_join, filter consolidation, nesting extraction)
+- 612 tests, 0 failures
+
 ### Page Editor
 **Status:** Future (Tier 4)
 
@@ -232,6 +242,7 @@ See: [docs/plans/page-builder.md](docs/plans/page-builder.md) for design
 
 | Feature | Commit | Notes |
 |---------|--------|-------|
+| CI pipeline | — | mix ci/precommit aliases, credo, dialyzer, 612 tests |
 | Default content pages | 5a43cfc | Generic Content LiveView, delivery/privacy/terms pages, 10 tests |
 | Transactional emails | — | Plain text order confirmation + shipping notification, 10 tests |
 | Printify order submission & fulfilment | — | Submit, track, webhooks, polling, admin UI, 33 tests |
diff --git a/lib/mix/tasks/generate_mockups.ex b/lib/mix/tasks/generate_mockups.ex
index e4541b0..2c43c50 100644
--- a/lib/mix/tasks/generate_mockups.ex
+++ b/lib/mix/tasks/generate_mockups.ex
@@ -129,7 +129,7 @@ defmodule Mix.Tasks.GenerateMockups do
 
     case MockupGenerator.search_blueprints(term) do
       results when is_list(results) ->
-        if length(results) == 0 do
+        if results == [] do
           Mix.shell().info("No blueprints found matching '#{term}'")
         else
           Mix.shell().info("\nMatching Blueprints:\n")
diff --git a/lib/simpleshop_theme/clients/printify.ex b/lib/simpleshop_theme/clients/printify.ex
index e483c22..7a8c029 100644
--- a/lib/simpleshop_theme/clients/printify.ex
+++ b/lib/simpleshop_theme/clients/printify.ex
@@ -89,7 +89,7 @@ defmodule SimpleshopTheme.Clients.Printify do
   """
   def get_shop_id do
     case get_shops() do
-      {:ok, shops} when is_list(shops) and length(shops) > 0 ->
+      {:ok, shops} when is_list(shops) and shops != [] ->
         {:ok, hd(shops)["id"]}
 
       {:ok, []} ->
diff --git a/lib/simpleshop_theme/mockups/generator.ex b/lib/simpleshop_theme/mockups/generator.ex
index 955f68c..8360f80 100644
--- a/lib/simpleshop_theme/mockups/generator.ex
+++ b/lib/simpleshop_theme/mockups/generator.ex
@@ -214,7 +214,7 @@ defmodule SimpleshopTheme.Mockups.Generator do
   """
   def find_print_provider(blueprint_id) do
     case Client.get_print_providers(blueprint_id) do
-      {:ok, providers} when is_list(providers) and length(providers) > 0 ->
+      {:ok, providers} when is_list(providers) and providers != [] ->
         # Just pick the first provider for simplicity
         {:ok, hd(providers)}
 
diff --git a/lib/simpleshop_theme/orders/fulfilment_status_worker.ex b/lib/simpleshop_theme/orders/fulfilment_status_worker.ex
index 0287795..254b1fc 100644
--- a/lib/simpleshop_theme/orders/fulfilment_status_worker.ex
+++ b/lib/simpleshop_theme/orders/fulfilment_status_worker.ex
@@ -23,24 +23,27 @@ defmodule SimpleshopTheme.Orders.FulfilmentStatusWorker do
       Logger.info("Polling fulfilment status for #{length(orders)} order(s)")
 
       Enum.each(orders, fn order ->
-        case Orders.refresh_fulfilment_status(order) do
-          {:ok, updated} ->
-            if updated.fulfilment_status != order.fulfilment_status do
-              Logger.info(
-                "Order #{order.order_number} status: #{order.fulfilment_status} → #{updated.fulfilment_status}"
-              )
-            end
-
-          {:error, reason} ->
-            Logger.warning(
-              "Failed to refresh status for order #{order.order_number}: #{inspect(reason)}"
-            )
-        end
-
+        refresh_order(order)
         Process.sleep(200)
       end)
 
       :ok
     end
   end
+
+  defp refresh_order(order) do
+    case Orders.refresh_fulfilment_status(order) do
+      {:ok, updated} ->
+        if updated.fulfilment_status != order.fulfilment_status do
+          Logger.info(
+            "Order #{order.order_number} status: #{order.fulfilment_status} → #{updated.fulfilment_status}"
+          )
+        end
+
+      {:error, reason} ->
+        Logger.warning(
+          "Failed to refresh status for order #{order.order_number}: #{inspect(reason)}"
+        )
+    end
+  end
 end
diff --git a/lib/simpleshop_theme/providers/printify.ex b/lib/simpleshop_theme/providers/printify.ex
index 9e56962..0037761 100644
--- a/lib/simpleshop_theme/providers/printify.ex
+++ b/lib/simpleshop_theme/providers/printify.ex
@@ -146,21 +146,22 @@ defmodule SimpleshopTheme.Providers.Printify do
       true ->
         with api_key when is_binary(api_key) <- ProviderConnection.get_api_key(conn),
              :ok <- set_api_key(api_key) do
-          results =
-            Enum.map(@webhook_events, fn event ->
-              case Client.create_webhook(shop_id, webhook_url, event, secret) do
-                {:ok, response} -> {:ok, event, response}
-                {:error, reason} -> {:error, event, reason}
-              end
-            end)
-
-          {:ok, results}
+          {:ok, create_all_webhooks(shop_id, webhook_url, secret)}
         else
           nil -> {:error, :no_api_key}
         end
     end
   end
 
+  defp create_all_webhooks(shop_id, webhook_url, secret) do
+    Enum.map(@webhook_events, fn event ->
+      case Client.create_webhook(shop_id, webhook_url, event, secret) do
+        {:ok, response} -> {:ok, event, response}
+        {:error, reason} -> {:error, event, reason}
+      end
+    end)
+  end
+
   @doc """
   Lists registered webhooks for the shop.
   """
diff --git a/lib/simpleshop_theme/theme/fonts.ex b/lib/simpleshop_theme/theme/fonts.ex
index 732aaeb..4824c16 100644
--- a/lib/simpleshop_theme/theme/fonts.ex
+++ b/lib/simpleshop_theme/theme/fonts.ex
@@ -128,9 +128,7 @@ defmodule SimpleshopTheme.Theme.Fonts do
         [heading_key, body_key]
       end
 
-    font_keys
-    |> Enum.map(&generate_font_face_for_font(&1, path_resolver))
-    |> Enum.join("\n")
+    Enum.map_join(font_keys, "\n", &generate_font_face_for_font(&1, path_resolver))
   end
 
   @doc """
@@ -143,8 +141,7 @@ defmodule SimpleshopTheme.Theme.Fonts do
   def generate_all_font_faces(path_resolver \\ &default_path_resolver/1) do
     @fonts
     |> Map.keys()
-    |> Enum.map(&generate_font_face_for_font(&1, path_resolver))
-    |> Enum.join("\n")
+    |> Enum.map_join("\n", &generate_font_face_for_font(&1, path_resolver))
   end
 
   @doc """
@@ -213,8 +210,7 @@ defmodule SimpleshopTheme.Theme.Fonts do
   defp generate_font_face_for_font(key, path_resolver) do
     case get_font(key) do
       %{family: family, file_prefix: prefix, weights: weights} ->
-        weights
-        |> Enum.map(fn weight ->
+        Enum.map_join(weights, "", fn weight ->
           weight_suffix = if weight == 400, do: "regular", else: to_string(weight)
           font_path = path_resolver.("/fonts/#{prefix}-#{weight_suffix}.woff2")
 
@@ -228,7 +224,6 @@ defmodule SimpleshopTheme.Theme.Fonts do
           }
           """
         end)
-        |> Enum.join("")
 
       nil ->
         ""
diff --git a/lib/simpleshop_theme/theme/preview_data.ex b/lib/simpleshop_theme/theme/preview_data.ex
index f73f8ee..8a2074e 100644
--- a/lib/simpleshop_theme/theme/preview_data.ex
+++ b/lib/simpleshop_theme/theme/preview_data.ex
@@ -393,8 +393,7 @@ defmodule SimpleshopTheme.Theme.PreviewData do
     # Get available variants for pricing
     available_variants =
       product.variants
-      |> Enum.filter(& &1.is_enabled)
-      |> Enum.filter(& &1.is_available)
+      |> Enum.filter(&(&1.is_enabled and &1.is_available))
 
     # Get the cheapest available variant for display price
     cheapest_variant =
diff --git a/lib/simpleshop_theme_web/components/shop_components/content.ex b/lib/simpleshop_theme_web/components/shop_components/content.ex
index 7b94337..520c28a 100644
--- a/lib/simpleshop_theme_web/components/shop_components/content.ex
+++ b/lib/simpleshop_theme_web/components/shop_components/content.ex
@@ -1199,7 +1199,6 @@ defmodule SimpleshopThemeWeb.ShopComponents.Content do
 
     widths
     |> Enum.sort()
-    |> Enum.map(&"#{base}#{separator}#{&1}.#{format} #{&1}w")
-    |> Enum.join(", ")
+    |> Enum.map_join(", ", &"#{base}#{separator}#{&1}.#{format} #{&1}w")
   end
 end
diff --git a/lib/simpleshop_theme_web/components/shop_components/product.ex b/lib/simpleshop_theme_web/components/shop_components/product.ex
index 450925f..95331e3 100644
--- a/lib/simpleshop_theme_web/components/shop_components/product.ex
+++ b/lib/simpleshop_theme_web/components/shop_components/product.ex
@@ -417,8 +417,7 @@ defmodule SimpleshopThemeWeb.ShopComponents.Product do
     gap_class = gap || ""
 
     [base, cols, gap_class, extra_class]
-    |> Enum.reject(&is_nil/1)
-    |> Enum.reject(&(&1 == ""))
+    |> Enum.reject(&(is_nil(&1) or &1 == ""))
     |> Enum.join(" ")
   end
 
diff --git a/lib/simpleshop_theme_web/controllers/checkout_controller.ex b/lib/simpleshop_theme_web/controllers/checkout_controller.ex
index 4c4f86c..fd1796b 100644
--- a/lib/simpleshop_theme_web/controllers/checkout_controller.ex
+++ b/lib/simpleshop_theme_web/controllers/checkout_controller.ex
@@ -10,14 +10,12 @@ defmodule SimpleshopThemeWeb.CheckoutController do
     cart_items = Cart.get_from_session(get_session(conn))
     hydrated = Cart.hydrate(cart_items)
 
-    cond do
-      hydrated == [] ->
-        conn
-        |> put_flash(:error, "Your basket is empty")
-        |> redirect(to: ~p"/cart")
-
-      true ->
-        create_checkout(conn, hydrated)
+    if hydrated == [] do
+      conn
+      |> put_flash(:error, "Your basket is empty")
+      |> redirect(to: ~p"/cart")
+    else
+      create_checkout(conn, hydrated)
     end
   end
 
diff --git a/mix.exs b/mix.exs
index 9aab2fd..68c29db 100644
--- a/mix.exs
+++ b/mix.exs
@@ -11,7 +11,8 @@ defmodule SimpleshopTheme.MixProject do
       aliases: aliases(),
       deps: deps(),
       compilers: [:phoenix_live_view] ++ Mix.compilers(),
-      listeners: [Phoenix.CodeReloader]
+      listeners: [Phoenix.CodeReloader],
+      dialyzer: [ignore_warnings: ".dialyzer_ignore.exs"]
     ]
   end
 
@@ -27,7 +28,7 @@ defmodule SimpleshopTheme.MixProject do
 
   def cli do
     [
-      preferred_envs: [precommit: :test]
+      preferred_envs: [precommit: :test, ci: :test]
     ]
   end
 
@@ -73,7 +74,9 @@ defmodule SimpleshopTheme.MixProject do
       {:oban, "~> 2.18"},
       {:ex_money, "~> 5.0"},
       {:ex_money_sql, "~> 1.0"},
-      {:stripity_stripe, "~> 3.2"}
+      {:stripity_stripe, "~> 3.2"},
+      {:credo, "~> 1.7", only: [:dev, :test], runtime: false},
+      {:dialyxir, "~> 1.4", only: [:dev, :test], runtime: false}
     ]
   end
 
@@ -102,7 +105,15 @@ defmodule SimpleshopTheme.MixProject do
         "esbuild simpleshop_theme --minify",
         "phx.digest"
       ],
-      precommit: ["compile --warning-as-errors", "deps.unlock --unused", "format", "test"]
+      precommit: ["compile --warning-as-errors", "deps.unlock --unused", "format", "test"],
+      ci: [
+        "compile --warning-as-errors",
+        "deps.unlock --unused",
+        "format --check-formatted",
+        "credo",
+        "dialyzer",
+        "test"
+      ]
     ]
   end
 end
diff --git a/mix.lock b/mix.lock
index 8e8a2fd..03adc77 100644
--- a/mix.lock
+++ b/mix.lock
@@ -1,19 +1,23 @@
 %{
   "bandit": {:hex, :bandit, "1.10.2", "d15ea32eb853b5b42b965b24221eb045462b2ba9aff9a0bda71157c06338cbff", [:mix], [{:hpax, "~> 1.0", [hex: :hpax, repo: "hexpm", optional: false]}, {:plug, "~> 1.18", [hex: :plug, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:thousand_island, "~> 1.0", [hex: :thousand_island, repo: "hexpm", optional: false]}, {:websock, "~> 0.5", [hex: :websock, repo: "hexpm", optional: false]}], "hexpm", "27b2a61b647914b1726c2ced3601473be5f7aa6bb468564a688646a689b3ee45"},
   "bcrypt_elixir": {:hex, :bcrypt_elixir, "3.3.2", "d50091e3c9492d73e17fc1e1619a9b09d6a5ef99160eb4d736926fd475a16ca3", [:make, :mix], [{:comeonin, "~> 5.3", [hex: :comeonin, repo: "hexpm", optional: false]}, {:elixir_make, "~> 0.6", [hex: :elixir_make, repo: "hexpm", optional: false]}], "hexpm", "471be5151874ae7931911057d1467d908955f93554f7a6cd1b7d804cac8cef53"},
+  "bunt": {:hex, :bunt, "1.0.0", "081c2c665f086849e6d57900292b3a161727ab40431219529f13c4ddcf3e7a44", [:mix], [], "hexpm", "dc5f86aa08a5f6fa6b8096f0735c4e76d54ae5c9fa2c143e5a1fc7c1cd9bb6b5"},
   "cc_precompiler": {:hex, :cc_precompiler, "0.1.11", "8c844d0b9fb98a3edea067f94f616b3f6b29b959b6b3bf25fee94ffe34364768", [:mix], [{:elixir_make, "~> 0.7", [hex: :elixir_make, repo: "hexpm", optional: false]}], "hexpm", "3427232caf0835f94680e5bcf082408a70b48ad68a5f5c0b02a3bea9f3a075b9"},
   "certifi": {:hex, :certifi, "2.15.0", "0e6e882fcdaaa0a5a9f2b3db55b1394dba07e8d6d9bcad08318fb604c6839712", [:rebar3], [], "hexpm", "b147ed22ce71d72eafdad94f055165c1c182f61a2ff49df28bcc71d1d5b94a60"},
   "circular_buffer": {:hex, :circular_buffer, "1.0.0", "25c004da0cba7bd8bc1bdabded4f9a902d095e20600fd15faf1f2ffbaea18a07", [:mix], [], "hexpm", "c829ec31c13c7bafd1f546677263dff5bfb006e929f25635878ac3cfba8749e5"},
   "cldr_utils": {:hex, :cldr_utils, "2.29.4", "11437b0bf9a0d57db4eccdf751c49f675a04fa4261c5dae1e23552a0347e25c9", [:mix], [{:castore, "~> 0.1 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:certifi, "~> 2.5", [hex: :certifi, repo: "hexpm", optional: true]}, {:decimal, "~> 1.9 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: false]}], "hexpm", "e72a43e69a3f546979085cbdbeae7e9049998cd21cedfdd796cff9155998114e"},
   "comeonin": {:hex, :comeonin, "5.5.1", "5113e5f3800799787de08a6e0db307133850e635d34e9fab23c70b6501669510", [:mix], [], "hexpm", "65aac8f19938145377cee73973f192c5645873dcf550a8a6b18187d17c13ccdb"},
+  "credo": {:hex, :credo, "1.7.16", "a9f1389d13d19c631cb123c77a813dbf16449a2aebf602f590defa08953309d4", [:mix], [{:bunt, "~> 0.2.1 or ~> 1.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:file_system, "~> 0.2 or ~> 1.0", [hex: :file_system, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "d0562af33756b21f248f066a9119e3890722031b6d199f22e3cf95550e4f1579"},
   "db_connection": {:hex, :db_connection, "2.8.1", "9abdc1e68c34c6163f6fb96a96532272d13ad7ca45262156ae8b7ec6d9dc4bec", [:mix], [{:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "a61a3d489b239d76f326e03b98794fb8e45168396c925ef25feb405ed09da8fd"},
   "decimal": {:hex, :decimal, "2.3.0", "3ad6255aa77b4a3c4f818171b12d237500e63525c2fd056699967a3e7ea20f62", [:mix], [], "hexpm", "a4d66355cb29cb47c3cf30e71329e58361cfcb37c34235ef3bf1d7bf3773aeac"},
+  "dialyxir": {:hex, :dialyxir, "1.4.7", "dda948fcee52962e4b6c5b4b16b2d8fa7d50d8645bbae8b8685c3f9ecb7f5f4d", [:mix], [{:erlex, ">= 0.2.8", [hex: :erlex, repo: "hexpm", optional: false]}], "hexpm", "b34527202e6eb8cee198efec110996c25c5898f43a4094df157f8d28f27d9efe"},
   "digital_token": {:hex, :digital_token, "1.0.0", "454a4444061943f7349a51ef74b7fb1ebd19e6a94f43ef711f7dae88c09347df", [:mix], [{:cldr_utils, "~> 2.17", [hex: :cldr_utils, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}], "hexpm", "8ed6f5a8c2fa7b07147b9963db506a1b4c7475d9afca6492136535b064c9e9e6"},
   "dns_cluster": {:hex, :dns_cluster, "0.2.0", "aa8eb46e3bd0326bd67b84790c561733b25c5ba2fe3c7e36f28e88f384ebcb33", [:mix], [], "hexpm", "ba6f1893411c69c01b9e8e8f772062535a4cf70f3f35bcc964a324078d8c8240"},
   "ecto": {:hex, :ecto, "3.13.5", "9d4a69700183f33bf97208294768e561f5c7f1ecf417e0fa1006e4a91713a834", [:mix], [{:decimal, "~> 2.0", [hex: :decimal, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "df9efebf70cf94142739ba357499661ef5dbb559ef902b68ea1f3c1fabce36de"},
   "ecto_sql": {:hex, :ecto_sql, "3.13.4", "b6e9d07557ddba62508a9ce4a484989a5bb5e9a048ae0e695f6d93f095c25d60", [:mix], [{:db_connection, "~> 2.4.1 or ~> 2.5", [hex: :db_connection, repo: "hexpm", optional: false]}, {:ecto, "~> 3.13.0", [hex: :ecto, repo: "hexpm", optional: false]}, {:myxql, "~> 0.7", [hex: :myxql, repo: "hexpm", optional: true]}, {:postgrex, "~> 0.19 or ~> 1.0", [hex: :postgrex, repo: "hexpm", optional: true]}, {:tds, "~> 2.1.1 or ~> 2.2", [hex: :tds, repo: "hexpm", optional: true]}, {:telemetry, "~> 0.4.0 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "2b38cf0749ca4d1c5a8bcbff79bbe15446861ca12a61f9fba604486cb6b62a14"},
   "ecto_sqlite3": {:hex, :ecto_sqlite3, "0.22.0", "edab2d0f701b7dd05dcf7e2d97769c106aff62b5cfddc000d1dd6f46b9cbd8c3", [:mix], [{:decimal, "~> 1.6 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: false]}, {:ecto, "~> 3.13.0", [hex: :ecto, repo: "hexpm", optional: false]}, {:ecto_sql, "~> 3.13.0", [hex: :ecto_sql, repo: "hexpm", optional: false]}, {:exqlite, "~> 0.22", [hex: :exqlite, repo: "hexpm", optional: false]}], "hexpm", "5af9e031bffcc5da0b7bca90c271a7b1e7c04a93fecf7f6cd35bc1b1921a64bd"},
   "elixir_make": {:hex, :elixir_make, "0.9.0", "6484b3cd8c0cee58f09f05ecaf1a140a8c97670671a6a0e7ab4dc326c3109726", [:mix], [], "hexpm", "db23d4fd8b757462ad02f8aa73431a426fe6671c80b200d9710caf3d1dd0ffdb"},
+  "erlex": {:hex, :erlex, "0.2.8", "cd8116f20f3c0afe376d1e8d1f0ae2452337729f68be016ea544a72f767d9c12", [:mix], [], "hexpm", "9d66ff9fedf69e49dc3fd12831e12a8a37b76f8651dd21cd45fcf5561a8a7590"},
   "esbuild": {:hex, :esbuild, "0.10.0", "b0aa3388a1c23e727c5a3e7427c932d89ee791746b0081bbe56103e9ef3d291f", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "468489cda427b974a7cc9f03ace55368a83e1a7be12fba7e30969af78e5f8c70"},
   "ex_cldr": {:hex, :ex_cldr, "2.46.0", "29b5bb638932ca4fc4339595145e327b797f59963a398c12a6aee1efe5a35b1b", [:mix], [{:cldr_utils, "~> 2.28", [hex: :cldr_utils, repo: "hexpm", optional: false]}, {:decimal, "~> 1.6 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: false]}, {:gettext, "~> 0.19 or ~> 1.0", [hex: :gettext, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:nimble_parsec, "~> 0.5 or ~> 1.0", [hex: :nimble_parsec, repo: "hexpm", optional: true]}], "hexpm", "14157ac16694e99c1339ac25a4f10d3df0e0d15cc1a35073b37e195487c1b6cb"},
   "ex_cldr_currencies": {:hex, :ex_cldr_currencies, "2.17.0", "c38d76339dbee413f7dd1aba4cdf05758bd4c0bbfe9c3b1c8602f96082c2890a", [:mix], [{:ex_cldr, "~> 2.38", [hex: :ex_cldr, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}], "hexpm", "9af59bd29407dcca59fa39ded8c1649ae1cf6ec29fd0611576dcad0279bce0db"},
diff --git a/test/simpleshop_theme/theme/preview_data_test.exs b/test/simpleshop_theme/theme/preview_data_test.exs
index 95982af..beaadc6 100644
--- a/test/simpleshop_theme/theme/preview_data_test.exs
+++ b/test/simpleshop_theme/theme/preview_data_test.exs
@@ -8,7 +8,7 @@ defmodule SimpleshopTheme.Theme.PreviewDataTest do
       products = PreviewData.products()
 
       assert is_list(products)
-      assert length(products) > 0
+      assert products != []
     end
 
     test "each product has required fields" do
@@ -62,7 +62,7 @@ defmodule SimpleshopTheme.Theme.PreviewDataTest do
       products = PreviewData.products()
       on_sale_products = Enum.filter(products, & &1.on_sale)
 
-      assert length(on_sale_products) > 0
+      assert on_sale_products != []
     end
 
     test "on-sale products have compare_at_price" do
@@ -80,7 +80,7 @@ defmodule SimpleshopTheme.Theme.PreviewDataTest do
       cart_items = PreviewData.cart_items()
 
       assert is_list(cart_items)
-      assert length(cart_items) > 0
+      assert cart_items != []
     end
 
     test "each cart item has required fields" do
@@ -120,7 +120,7 @@ defmodule SimpleshopTheme.Theme.PreviewDataTest do
       testimonials = PreviewData.testimonials()
 
       assert is_list(testimonials)
-      assert length(testimonials) > 0
+      assert testimonials != []
     end
 
     test "each testimonial has required fields" do
@@ -160,7 +160,7 @@ defmodule SimpleshopTheme.Theme.PreviewDataTest do
       categories = PreviewData.categories()
 
       assert is_list(categories)
-      assert length(categories) > 0
+      assert categories != []
     end
 
     test "each category has required fields" do