diff --git a/cli/elm.json b/cli/elm.json
index dc2378d..e9cd43c 100644
--- a/cli/elm.json
+++ b/cli/elm.json
@@ -21,6 +21,7 @@
             "mdgriffith/elm-codegen": "6.0.1",
             "miniBill/elm-fast-dict": "1.2.4",
             "robinheghan/murmur3": "1.0.0",
+            "the-sett/elm-pretty-printer": "3.3.0",
             "wolfadex/elm-ansi": "3.0.1",
             "wolfadex/elm-open-api": "2.0.0"
         },
@@ -60,7 +61,6 @@
             "rtfeldman/elm-iso8601-date-strings": "1.1.4",
             "stil4m/elm-syntax": "7.3.9",
             "stil4m/structured-writer": "1.0.3",
-            "the-sett/elm-pretty-printer": "3.3.0",
             "the-sett/elm-syntax-dsl": "6.0.3",
             "zwilias/elm-utf-tools": "2.0.1"
         }
diff --git a/cli/review/suppressed/NoInternalImports.json b/cli/review/suppressed/NoInternalImports.json
index ff8a17e..9898a85 100644
--- a/cli/review/suppressed/NoInternalImports.json
+++ b/cli/review/suppressed/NoInternalImports.json
@@ -3,6 +3,6 @@
   "automatically created by": "elm-review suppress",
   "learn more": "elm-review suppress --help",
   "suppressions": [
-    { "count": 3, "filePath": "src/Cli.elm" }
+    { "count": 2, "filePath": "src/Cli.elm" }
   ]
 }
diff --git a/cli/src/Cli.elm b/cli/src/Cli.elm
index e853ae5..af56e12 100644
--- a/cli/src/Cli.elm
+++ b/cli/src/Cli.elm
@@ -18,20 +18,18 @@ import Elm
 import FastDict
 import FastSet
 import FatalError exposing (FatalError)
-import IndentedString exposing (IndentedString)
 import Json.Decode
 import Json.Encode
 import Json.Value
-import List.Extra
 import OpenApi
 import OpenApi.Common.Internal
 import OpenApi.Config
 import OpenApi.Generate
 import Pages.Script
 import Pages.Script.Spinner
+import Pretty
 import Regex exposing (Regex)
 import Result.Extra
-import Set
 import String.Extra
 import Url
 import UrlPath
@@ -983,6 +981,11 @@ yamlToJsonValueDecoder =
         ]
 
 
+width : Int
+width =
+    120
+
+
 generateFilesFromOpenApiSpecs :
     List ( OpenApi.Config.Generate, OpenApi.OpenApi )
     ->
@@ -1002,7 +1005,7 @@ generateFilesFromOpenApiSpecs configs =
                         (\err ->
                             err
                                 |> messageToString
-                                |> IndentedString.toString
+                                |> Pretty.pretty width
                                 |> FatalError.fromString
                         )
                     |> BackendTask.fromResult
@@ -1155,10 +1158,6 @@ printSuccessMessageAndWarnings :
     -> BackendTask.BackendTask FatalError.FatalError ()
 printSuccessMessageAndWarnings ( outputPaths, { requiredPackages, warnings } ) =
     let
-        indentBy : Int -> String -> String
-        indentBy amount input =
-            String.repeat amount " " ++ input
-
         allRequiredPackages : List String
         allRequiredPackages =
             requiredPackages
@@ -1168,9 +1167,9 @@ printSuccessMessageAndWarnings ( outputPaths, { requiredPackages, warnings } ) =
                 |> FastSet.insert "elm/bytes"
                 |> FastSet.toList
 
-        toInstall : String -> String
+        toInstall : String -> Pretty.Doc ()
         toInstall dependency =
-            "elm install " ++ dependency
+            Pretty.string ("elm install " ++ dependency)
 
         toSentence : List String -> String
         toSentence links =
@@ -1185,61 +1184,75 @@ printSuccessMessageAndWarnings ( outputPaths, { requiredPackages, warnings } ) =
                 , url = "https://package.elm-lang.org/packages/" ++ dependency ++ "/latest/"
                 }
 
-        warningTask : BackendTask.BackendTask FatalError.FatalError ()
-        warningTask =
+        warningString : Pretty.Doc ()
+        warningString =
             let
                 len : Int
                 len =
                     List.length warnings
             in
             if len == 0 then
-                BackendTask.succeed ()
+                Pretty.empty
 
             else
                 let
-                    warningTasks : List (BackendTask FatalError ())
-                    warningTasks =
+                    joined : Pretty.Doc ()
+                    joined =
                         warnings
                             |> Dict.Extra.groupBy .message
                             |> Dict.toList
-                            |> List.map logWarning
+                            |> List.map warningToString
+                            |> Pretty.lines
 
-                    countMessage : String
+                    countMessage : Pretty.Doc ()
                     countMessage =
                         if len == 1 then
-                            "\nGenerated 1" ++ Ansi.Color.fontColor Ansi.Color.yellow " warning" ++ "."
+                            [ ""
+                            , "Generated 1" ++ Ansi.Color.fontColor Ansi.Color.yellow " warning" ++ "."
+                            ]
+                                |> List.map Pretty.string
+                                |> Pretty.lines
 
                         else
-                            "\nGenerated " ++ String.fromInt len ++ Ansi.Color.fontColor Ansi.Color.yellow " warnings" ++ "."
+                            [ ""
+                            , "Generated " ++ String.fromInt len ++ Ansi.Color.fontColor Ansi.Color.yellow " warnings" ++ "."
+                            ]
+                                |> List.map Pretty.string
+                                |> Pretty.lines
                 in
-                (Pages.Script.log "" :: warningTasks ++ [ Pages.Script.log countMessage ])
-                    |> BackendTask.doEach
+                [ Pretty.string ""
+                , joined
+                , countMessage
+                ]
+                    |> Pretty.lines
 
-        successTask : BackendTask.BackendTask error ()
+        successTask : Pretty.Doc ()
         successTask =
-            [ [ ""
-              , "🎉 SDK generated:"
-              , ""
+            [ [ Pretty.string ""
+              , Pretty.string "🎉 SDK generated:"
+              , Pretty.string ""
               ]
+                |> Pretty.lines
             , outputPaths
-                |> List.map (indentBy 4)
-            , [ ""
-              , ""
-              , "You'll also need " ++ toSentence allRequiredPackages ++ " installed. Try running:"
-              , ""
+                |> List.map (\path -> Pretty.string path |> Pretty.indent 4)
+                |> Pretty.lines
+            , [ Pretty.string ""
+              , Pretty.string ""
+              , Pretty.string ("You'll also need " ++ toSentence allRequiredPackages ++ " installed. Try running:")
+              , Pretty.string ""
               ]
+                |> Pretty.lines
             , allRequiredPackages
                 |> List.map
                     (\requiredPackage ->
                         toInstall requiredPackage
-                            |> indentBy 4
+                            |> Pretty.indent 4
                     )
+                |> Pretty.lines
             ]
-                |> List.concat
-                |> List.map Pages.Script.log
-                |> BackendTask.doEach
+                |> Pretty.lines
     in
-    BackendTask.doEach [ successTask, warningTask ]
+    Pages.Script.log (Pretty.pretty width (Pretty.lines [ successTask, warningString ]))
 
 
 elmCodegenWarningToMessage : ( String, List { declaration : String, warning : String } ) -> List OpenApi.Generate.Message
@@ -1247,60 +1260,60 @@ elmCodegenWarningToMessage ( path, warnings ) =
     List.map
         (\warning ->
             { message = warning.warning
-            , details = []
             , path = [ path, warning.declaration ]
+            , details = Pretty.empty
             }
         )
         warnings
 
 
-messageToString : OpenApi.Generate.Message -> List IndentedString
+messageToString : OpenApi.Generate.Message -> Pretty.Doc ()
 messageToString { path, message, details } =
-    [ IndentedString.fromString ("Error! " ++ message)
+    [ Pretty.string ("Error! " ++ message)
     , if List.isEmpty path then
-        []
+        Pretty.empty
 
       else
-        IndentedString.fromString ("Path: " ++ String.join " -> " path)
-    , if List.isEmpty details then
-        []
+        Pretty.string ("Path: " ++ String.join " -> " path)
+    , if details == Pretty.empty then
+        Pretty.empty
 
       else
-        IndentedString.indent 2 (IndentedString.fromString "Details:")
-            ++ IndentedString.indent 4 details
+        [ Pretty.string "Details:"
+        , details
+        ]
+            |> Pretty.lines
+            |> Pretty.nest 2
     ]
-        |> List.concat
+        |> Pretty.lines
 
 
-logWarning : ( String, List OpenApi.Generate.Message ) -> BackendTask.BackendTask FatalError.FatalError ()
-logWarning ( message, messages ) =
+warningToString : ( String, List OpenApi.Generate.Message ) -> Pretty.Doc ()
+warningToString ( message, messages ) =
     let
-        firstLine : String
+        firstLine : Pretty.Doc ()
         firstLine =
-            Ansi.Color.fontColor Ansi.Color.brightYellow "Warning: " ++ message
+            Pretty.string (Ansi.Color.fontColor Ansi.Color.brightYellow "Warning: " ++ message)
 
-        paths : List String
+        paths : List (Pretty.Doc ())
         paths =
             messages
                 |> List.map
                     (\{ path, details } ->
-                        (if List.isEmpty path then
+                        if List.isEmpty path then
                             details
 
-                         else
-                            IndentedString.fromString (Ansi.Font.bold "at " ++ String.join " -> " path)
-                                ++ IndentedString.indent 2 details
-                        )
-                            |> IndentedString.indent 2
+                        else
+                            [ Pretty.string (Ansi.Font.bold "at " ++ String.join " -> " path)
+                            , details
+                            ]
+                                |> Pretty.lines
+                                |> Pretty.nest 2
                     )
-                |> List.Extra.removeWhen List.isEmpty
-                |> List.map IndentedString.toString
-                |> Set.fromList
-                |> Set.toList
     in
     (firstLine :: paths)
-        |> List.map Pages.Script.log
-        |> BackendTask.doEach
+        |> Pretty.lines
+        |> Pretty.nest 2
 
 
 
diff --git a/elm.json b/elm.json
index 5cc648d..c9b96c8 100644
--- a/elm.json
+++ b/elm.json
@@ -19,6 +19,7 @@
         "mdgriffith/elm-codegen": "6.0.1 <= v < 7.0.0",
         "miniBill/elm-fast-dict": "1.2.0 <= v < 2.0.0",
         "robinheghan/murmur3": "1.0.0 <= v < 2.0.0",
+        "the-sett/elm-pretty-printer": "3.3.0 <= v < 4.0.0",
         "wolfadex/elm-open-api": "2.0.0 <= v < 3.0.0"
     },
     "test-dependencies": {
diff --git a/review/suppressed/NoMissingTypeExpose.json b/review/suppressed/NoMissingTypeExpose.json
index d1bab4d..56dc427 100644
--- a/review/suppressed/NoMissingTypeExpose.json
+++ b/review/suppressed/NoMissingTypeExpose.json
@@ -4,6 +4,6 @@
   "learn more": "elm-review suppress --help",
   "suppressions": [
     { "count": 4, "filePath": "src/OpenApi/Config.elm" },
-    { "count": 2, "filePath": "src/OpenApi/Generate.elm" }
+    { "count": 1, "filePath": "src/OpenApi/Generate.elm" }
   ]
 }
diff --git a/review/suppressed/NoUnused.Exports.json b/review/suppressed/NoUnused.Exports.json
index f251531..179de1b 100644
--- a/review/suppressed/NoUnused.Exports.json
+++ b/review/suppressed/NoUnused.Exports.json
@@ -3,7 +3,6 @@
   "automatically created by": "elm-review suppress",
   "learn more": "elm-review suppress --help",
   "suppressions": [
-    { "count": 1, "filePath": "src/IndentedString.elm" },
     { "count": 1, "filePath": "src/OpenApi/Common/Internal.elm" }
   ]
 }
diff --git a/src/CliMonad.elm b/src/CliMonad.elm
index ca7b8dc..5f98004 100644
--- a/src/CliMonad.elm
+++ b/src/CliMonad.elm
@@ -33,17 +33,17 @@ import FastSet
 import Gen.Debug
 import Gen.Json.Decode
 import Gen.Json.Encode
-import IndentedString exposing (IndentedString)
 import Json.Encode
 import OpenApi exposing (OpenApi)
 import OpenApi.Config
+import Pretty
 import String.Extra
 
 
 type alias Message =
     { message : String
     , path : Path
-    , details : List IndentedString
+    , details : Pretty.Doc ()
     }
 
 
@@ -241,7 +241,14 @@ withWarning message (CliMonad f) =
             Result.map
                 (\( res, output, cache2 ) ->
                     ( res
-                    , { output | warnings = { path = [], message = message, details = [] } :: output.warnings }
+                    , { output
+                        | warnings =
+                            { path = []
+                            , message = message
+                            , details = Pretty.empty
+                            }
+                                :: output.warnings
+                      }
                     , cache2
                     )
                 )
@@ -249,14 +256,21 @@ withWarning message (CliMonad f) =
         )
 
 
-withExtendedWarning : { message : String, details : List IndentedString } -> CliMonad a -> CliMonad a
+withExtendedWarning : { message : String, details : Pretty.Doc () } -> CliMonad a -> CliMonad a
 withExtendedWarning { message, details } (CliMonad f) =
     CliMonad
         (\input cache ->
             Result.map
                 (\( res, output, cache2 ) ->
                     ( res
-                    , { output | warnings = { path = [], message = message, details = details } :: output.warnings }
+                    , { output
+                        | warnings =
+                            { path = []
+                            , message = message
+                            , details = details
+                            }
+                                :: output.warnings
+                      }
                     , cache2
                     )
                 )
@@ -276,7 +290,14 @@ todoWithDefault default message =
             if generateTodos then
                 Ok
                     ( default
-                    , { emptyOutput | warnings = [ { path = [], message = message, details = [] } ] }
+                    , { emptyOutput
+                        | warnings =
+                            [ { path = []
+                              , message = message
+                              , details = Pretty.empty
+                              }
+                            ]
+                      }
                     , cache
                     )
 
@@ -284,14 +305,14 @@ todoWithDefault default message =
                 Err
                     { path = []
                     , message = "Todo: " ++ message
-                    , details = []
+                    , details = Pretty.empty
                     }
         )
 
 
 fail : String -> CliMonad a
 fail message =
-    CliMonad (\_ _ -> Err { path = [], message = message, details = [] })
+    CliMonad (\_ _ -> Err { path = [], message = message, details = Pretty.empty })
 
 
 succeed : a -> CliMonad a
@@ -544,7 +565,7 @@ errorToWarning (CliMonad f) =
 
                 Err { path, message } ->
                     ( Nothing
-                    , { emptyOutput | warnings = [ { path = path, message = message, details = [] } ] }
+                    , { emptyOutput | warnings = [ { path = path, message = message, details = Pretty.empty } ] }
                     , cache
                     )
                         |> Ok
@@ -622,7 +643,7 @@ enumName variants =
                             | warnings =
                                 [ { path = []
                                   , message = message
-                                  , details = []
+                                  , details = Pretty.empty
                                   }
                                 ]
                           }
@@ -735,7 +756,7 @@ withFormat basicType maybeFormatName getter default =
                                     | warnings =
                                         [ { message = firstLine ++ "\n" ++ secondLine
                                           , path = [ "format" ]
-                                          , details = []
+                                          , details = Pretty.empty
                                           }
                                         ]
                                 }
diff --git a/src/IndentedString.elm b/src/IndentedString.elm
deleted file mode 100644
index df75897..0000000
--- a/src/IndentedString.elm
+++ /dev/null
@@ -1,35 +0,0 @@
-module IndentedString exposing (IndentedString, fromString, indent, listItem, toString)
-
-
-type IndentedString
-    = IndentedString Int String
-
-
-fromString : String -> List IndentedString
-fromString input =
-    input
-        |> String.lines
-        |> List.map (IndentedString 0)
-
-
-indent : Int -> List IndentedString -> List IndentedString
-indent i ls =
-    List.map (\(IndentedString j l) -> IndentedString (i + j) l) ls
-
-
-toString : List IndentedString -> String
-toString ls =
-    ls
-        |> List.map (\(IndentedString i l) -> String.repeat i " " ++ l)
-        |> String.join "\n"
-
-
-listItem : String -> List IndentedString -> List IndentedString
-listItem s ls =
-    case ls of
-        [] ->
-            []
-
-        (IndentedString j h) :: t ->
-            IndentedString j (s ++ " " ++ h)
-                :: indent (String.length s + 1) t
diff --git a/src/OpenApi/Generate.elm b/src/OpenApi/Generate.elm
index c3e7029..32ac5f2 100644
--- a/src/OpenApi/Generate.elm
+++ b/src/OpenApi/Generate.elm
@@ -36,7 +36,6 @@ import Gen.Maybe
 import Gen.String
 import Gen.Task
 import Gen.Url.Builder
-import IndentedString exposing (IndentedString)
 import Json.Schema.Definitions
 import JsonSchema.Generate
 import List.Extra
@@ -56,6 +55,7 @@ import OpenApi.Schema
 import OpenApi.SecurityRequirement
 import OpenApi.SecurityScheme
 import OpenApi.Server
+import Pretty
 import Regex exposing (Regex)
 import SchemaUtils
 import String.Extra
@@ -70,7 +70,7 @@ type alias Mime =
 type alias Message =
     { message : String
     , path : Path
-    , details : List IndentedString
+    , details : Pretty.Doc ()
     }
 
 
@@ -214,7 +214,7 @@ extractEnums openApi =
                                         Err
                                             { message = e
                                             , path = [ name, "Extracting enums" ]
-                                            , details = []
+                                            , details = Pretty.empty
                                             }
 
                             _ ->
diff --git a/src/SchemaUtils.elm b/src/SchemaUtils.elm
index d0fc9f7..63b245e 100644
--- a/src/SchemaUtils.elm
+++ b/src/SchemaUtils.elm
@@ -34,7 +34,6 @@ import Gen.List
 import Gen.Maybe
 import Gen.Result
 import Gen.String
-import IndentedString exposing (IndentedString)
 import IntersectionResult exposing (IntersectionResult)
 import Json.Decode
 import Json.Encode
@@ -48,6 +47,7 @@ import OpenApi
 import OpenApi.Common.Internal
 import OpenApi.Components
 import OpenApi.Schema
+import Pretty
 import Result.Extra
 import Set exposing (Set)
 
@@ -257,7 +257,7 @@ schemaToType seen schema =
                             (\disjoint ->
                                 let
                                     onIntersection :
-                                        { a | leftSchema : List IndentedString, rightSchema : List IndentedString }
+                                        { a | leftSchema : Pretty.Doc (), rightSchema : Pretty.Doc () }
                                         -> Maybe Json.Encode.Value
                                         -> CliMonad { type_ : Common.Type, documentation : Maybe String }
                                     onIntersection collision value =
@@ -273,31 +273,35 @@ schemaToType seen schema =
 
                                             Nothing ->
                                                 let
-                                                    formatSchema : List IndentedString -> List IndentedString
+                                                    formatSchema : Pretty.Doc () -> Pretty.Doc ()
                                                     formatSchema s =
-                                                        s
-                                                            |> IndentedString.listItem "-"
+                                                        Pretty.string "- "
+                                                            |> Pretty.a s
+                                                            |> Pretty.nest 2
 
-                                                    details : List IndentedString
+                                                    details : Pretty.Doc ()
                                                     details =
                                                         case value of
                                                             Just found ->
-                                                                [ IndentedString.fromString "Clash between"
+                                                                [ Pretty.string "Clash between"
                                                                 , formatSchema collision.leftSchema
                                                                 , formatSchema collision.rightSchema
-                                                                , IndentedString.fromString "Possible clashing value:"
-                                                                , IndentedString.fromString (Json.Encode.encode 2 found)
-                                                                    |> IndentedString.indent 2
+                                                                , Pretty.string "Possible clashing value:"
+                                                                , Json.Encode.encode 2 found
+                                                                    |> String.lines
+                                                                    |> List.map Pretty.string
+                                                                    |> Pretty.lines
+                                                                    |> Pretty.indent 2
                                                                 ]
-                                                                    |> List.concat
+                                                                    |> Pretty.lines
 
                                                             Nothing ->
-                                                                [ IndentedString.fromString "Clash between"
+                                                                [ Pretty.string "Clash between"
                                                                 , formatSchema collision.leftSchema
                                                                 , formatSchema collision.rightSchema
-                                                                , IndentedString.fromString "Could not build a clashing value"
+                                                                , Pretty.string "Could not build a clashing value"
                                                                 ]
-                                                                    |> List.concat
+                                                                    |> Pretty.lines
                                                 in
                                                 CliMonad.succeed
                                                     { type_ = Common.Value
@@ -532,13 +536,13 @@ areAllArrays schemas =
 type SchemaIntersectionResult
     = NoSchemaIntersection
     | SchemaMayIntersect
-        { leftSchema : List IndentedString
-        , rightSchema : List IndentedString
+        { leftSchema : Pretty.Doc ()
+        , rightSchema : Pretty.Doc ()
         }
     | FoundSchemaIntersection
-        { leftSchema : List IndentedString
+        { leftSchema : Pretty.Doc ()
         , value : Json.Encode.Value
-        , rightSchema : List IndentedString
+        , rightSchema : Pretty.Doc ()
         }
 
 
@@ -550,9 +554,9 @@ schemaIntersection seen schemas =
             case ( l, r ) of
                 ( Json.Schema.Definitions.BooleanSchema lb, Json.Schema.Definitions.BooleanSchema rb ) ->
                     if lb == rb then
-                        { leftSchema = IndentedString.fromString "bool"
+                        { leftSchema = Pretty.string "bool"
                         , value = Json.Encode.bool lb
-                        , rightSchema = IndentedString.fromString "bool"
+                        , rightSchema = Pretty.string "bool"
                         }
                             |> FoundSchemaIntersection
                             |> CliMonad.succeed
@@ -634,16 +638,16 @@ schemaIntersection seen schemas =
     go (LazyList.uniquePairs lazyList) NoSchemaIntersection
 
 
-describeSubSchema : Json.Schema.Definitions.SubSchema -> CliMonad (List IndentedString)
+describeSubSchema : Json.Schema.Definitions.SubSchema -> CliMonad (Pretty.Doc ())
 describeSubSchema subSchema =
     let
-        sourceToString : Json.Decode.Value -> List IndentedString
+        sourceToString : Json.Decode.Value -> Pretty.Doc ()
         sourceToString source =
             source
                 |> Json.Decode.decodeValue removeDocumentation
                 |> Result.withDefault subSchema.source
                 |> Json.Encode.encode 0
-                |> IndentedString.fromString
+                |> Pretty.string
     in
     case subSchema.ref of
         Nothing ->
@@ -663,8 +667,8 @@ describeSubSchema subSchema =
                                     Json.Schema.Definitions.BooleanSchema b ->
                                         Json.Encode.bool b
                         in
-                        IndentedString.fromString (ref ++ ":")
-                            ++ sourceToString source
+                        Pretty.string (ref ++ ": ")
+                            |> Pretty.a (sourceToString source)
                     )