diff --git a/promkit/src/lib.rs b/promkit/src/lib.rs
index 72922934..22730030 100644
--- a/promkit/src/lib.rs
+++ b/promkit/src/lib.rs
@@ -223,12 +223,13 @@ pub trait Renderer: Finalizer {
 /// event handling, and result production for a prompt.
 pub struct Prompt<T: Renderer> {
     pub renderer: T,
+    pub writer: Box<dyn io::Write>,
 }
 
 impl<T: Renderer> Drop for Prompt<T> {
     fn drop(&mut self) {
         execute!(
-            io::stdout(),
+            self.writer,
             cursor::Show,
             event::DisableMouseCapture,
             cursor::MoveToNextLine(1),
@@ -250,11 +251,11 @@ impl<T: Renderer> Prompt<T> {
     /// Returns a `Result` containing the produced result or an error.
     pub fn run(&mut self) -> anyhow::Result<T::Return> {
         enable_raw_mode()?;
-        execute!(io::stdout(), cursor::Hide)?;
+        execute!(self.writer, cursor::Hide)?;
 
         let size = crossterm::terminal::size()?;
         let panes = self.renderer.create_panes(size.0, size.1);
-        let mut terminal = Terminal::start_session(&panes)?;
+        let mut terminal = Terminal::start_session(&panes, &mut self.writer)?;
         terminal.draw(&panes)?;
 
         loop {
@@ -262,11 +263,7 @@ impl<T: Renderer> Prompt<T> {
 
             match &ev {
                 Event::Resize(_, _) => {
-                    terminal.position = (0, 0);
-                    crossterm::execute!(
-                        io::stdout(),
-                        crossterm::terminal::Clear(crossterm::terminal::ClearType::Purge),
-                    )?;
+                    terminal.on_resize()?;
                 }
                 _ => {
                     if self.renderer.evaluate(&ev)? == PromptSignal::Quit {
diff --git a/promkit/src/preset/checkbox.rs b/promkit/src/preset/checkbox.rs
index de4c6851..77d1c1f6 100644
--- a/promkit/src/preset/checkbox.rs
+++ b/promkit/src/preset/checkbox.rs
@@ -1,4 +1,4 @@
-use std::{cell::RefCell, fmt::Display};
+use std::{cell::RefCell, fmt::Display, io};
 
 use crate::{
     checkbox,
@@ -20,6 +20,8 @@ pub struct Checkbox {
     title_state: text::State,
     /// State for the checkbox list itself.
     checkbox_state: checkbox::State,
+    /// Writer to which promptkit write its contents
+    writer: Box<dyn io::Write>,
 }
 
 impl Checkbox {
@@ -48,6 +50,7 @@ impl Checkbox {
                 lines: Default::default(),
             },
             keymap: ActiveKeySwitcher::new("default", self::keymap::default),
+            writer: Box::new(io::stdout()),
         }
     }
 
@@ -69,6 +72,7 @@ impl Checkbox {
                 lines: Default::default(),
             },
             keymap: ActiveKeySwitcher::new("default", self::keymap::default),
+            writer: Box::new(io::stdout()),
         }
     }
 
@@ -119,6 +123,12 @@ impl Checkbox {
         self
     }
 
+    /// Sets writer.
+    pub fn writer<W: io::Write + 'static>(mut self, writer: W) -> Self {
+        self.writer = Box::new(writer);
+        self
+    }
+
     /// Displays the checkbox prompt and waits for user input.
     /// Returns a `Result` containing the `Prompt` result,
     /// which is a list of selected options.
@@ -129,6 +139,7 @@ impl Checkbox {
                 title_snapshot: Snapshot::<text::State>::new(self.title_state),
                 checkbox_snapshot: Snapshot::<checkbox::State>::new(self.checkbox_state),
             },
+            writer: self.writer,
         })
     }
 }
diff --git a/promkit/src/preset/form.rs b/promkit/src/preset/form.rs
index 786cd51e..0045fde7 100644
--- a/promkit/src/preset/form.rs
+++ b/promkit/src/preset/form.rs
@@ -1,4 +1,4 @@
-use std::cell::RefCell;
+use std::{cell::RefCell, io};
 
 use crate::{
     core::Cursor,
@@ -17,6 +17,8 @@ pub struct Form {
     text_editor_states: Vec<text_editor::State>,
     /// Overwrite the default styles of text editor states when unselected.
     overwrite_styles: Vec<render::Style>,
+    /// Writer to which promptkit write its contents
+    writer: Box<dyn io::Write>,
 }
 
 impl Form {
@@ -42,9 +44,16 @@ impl Form {
             keymap: ActiveKeySwitcher::new("default", self::keymap::default as keymap::Keymap),
             text_editor_states,
             overwrite_styles,
+            writer: Box::new(io::stdout()),
         }
     }
 
+    /// Sets writer.
+    pub fn writer<W: io::Write + 'static>(mut self, writer: W) -> Self {
+        self.writer = Box::new(writer);
+        self
+    }
+
     pub fn prompt(self) -> anyhow::Result<Prompt<render::Renderer>> {
         let default_styles = self
             .text_editor_states
@@ -62,6 +71,9 @@ impl Form {
             overwrite_styles: self.overwrite_styles,
         };
         renderer.overwrite_styles();
-        Ok(Prompt { renderer })
+        Ok(Prompt {
+            renderer,
+            writer: self.writer,
+        })
     }
 }
diff --git a/promkit/src/preset/json.rs b/promkit/src/preset/json.rs
index 2149664e..d89e2633 100644
--- a/promkit/src/preset/json.rs
+++ b/promkit/src/preset/json.rs
@@ -1,4 +1,4 @@
-use std::cell::RefCell;
+use std::{cell::RefCell, io};
 
 use crate::{
     crossterm::style::{Attribute, Attributes, Color, ContentStyle},
@@ -17,6 +17,8 @@ pub struct Json {
     keymap: ActiveKeySwitcher<keymap::Keymap>,
     title_state: text::State,
     json_state: json::State,
+    /// Writer to which promptkit write its contents
+    writer: Box<dyn io::Write>,
 }
 
 impl Json {
@@ -47,6 +49,7 @@ impl Json {
                 indent: 2,
             },
             keymap: ActiveKeySwitcher::new("default", self::keymap::default),
+            writer: Box::new(io::stdout()),
         }
     }
 
@@ -91,6 +94,12 @@ impl Json {
         self
     }
 
+    /// Sets writer.
+    pub fn writer<W: io::Write + 'static>(mut self, writer: W) -> Self {
+        self.writer = Box::new(writer);
+        self
+    }
+
     /// Creates a prompt based on the current configuration of the `Json` instance.
     pub fn prompt(self) -> anyhow::Result<Prompt<render::Renderer>> {
         Ok(Prompt {
@@ -99,6 +108,7 @@ impl Json {
                 title_snapshot: Snapshot::<text::State>::new(self.title_state),
                 json_snapshot: Snapshot::<json::State>::new(self.json_state),
             },
+            writer: self.writer,
         })
     }
 }
diff --git a/promkit/src/preset/listbox.rs b/promkit/src/preset/listbox.rs
index e27f8f79..f1fd27d9 100644
--- a/promkit/src/preset/listbox.rs
+++ b/promkit/src/preset/listbox.rs
@@ -1,4 +1,4 @@
-use std::{cell::RefCell, fmt::Display};
+use std::{cell::RefCell, fmt::Display, io};
 
 use crate::{
     crossterm::style::{Attribute, Attributes, Color, ContentStyle},
@@ -19,6 +19,8 @@ pub struct Listbox {
     title_state: text::State,
     /// State for the selectable list itself.
     listbox_state: listbox::State,
+    /// Writer to which promptkit write its contents
+    writer: Box<dyn io::Write>,
 }
 
 impl Listbox {
@@ -45,6 +47,7 @@ impl Listbox {
                 lines: Default::default(),
             },
             keymap: ActiveKeySwitcher::new("default", self::keymap::default),
+            writer: Box::new(io::stdout()),
         }
     }
 
@@ -89,6 +92,12 @@ impl Listbox {
         self
     }
 
+    /// Sets writer.
+    pub fn writer<W: io::Write + 'static>(mut self, writer: W) -> Self {
+        self.writer = Box::new(writer);
+        self
+    }
+
     /// Displays the select prompt and waits for user input.
     /// Returns a `Result` containing the `Prompt` result,
     /// which is the selected option.
@@ -99,6 +108,7 @@ impl Listbox {
                 title_snapshot: Snapshot::<text::State>::new(self.title_state),
                 listbox_snapshot: Snapshot::<listbox::State>::new(self.listbox_state),
             },
+            writer: self.writer,
         })
     }
 }
diff --git a/promkit/src/preset/query_selector.rs b/promkit/src/preset/query_selector.rs
index a2c679a0..f17673b5 100644
--- a/promkit/src/preset/query_selector.rs
+++ b/promkit/src/preset/query_selector.rs
@@ -1,4 +1,4 @@
-use std::{cell::RefCell, fmt::Display};
+use std::{cell::RefCell, fmt::Display, io};
 
 use crate::{
     crossterm::style::{Attribute, Attributes, Color, ContentStyle},
@@ -28,6 +28,8 @@ pub struct QuerySelector {
     /// A filter function to apply to the list box items
     /// based on the text editor input.
     filter: render::Filter,
+    /// Writer to which promptkit write its contents
+    writer: Box<dyn io::Write>,
 }
 
 impl QuerySelector {
@@ -74,6 +76,7 @@ impl QuerySelector {
             },
             keymap: ActiveKeySwitcher::new("default", self::keymap::default),
             filter,
+            writer: Box::new(io::stdout()),
         }
     }
 
@@ -154,6 +157,12 @@ impl QuerySelector {
         self
     }
 
+    /// Sets writer.
+    pub fn writer<W: io::Write + 'static>(mut self, writer: W) -> Self {
+        self.writer = Box::new(writer);
+        self
+    }
+
     /// Displays the query select prompt and waits for user input.
     /// Returns a `Result` containing the `Prompt` result,
     /// which is the selected option.
@@ -166,6 +175,7 @@ impl QuerySelector {
                 listbox_snapshot: Snapshot::<listbox::State>::new(self.listbox_state),
                 filter: self.filter,
             },
+            writer: self.writer,
         })
     }
 }
diff --git a/promkit/src/preset/readline.rs b/promkit/src/preset/readline.rs
index 85875c5b..84e6e960 100644
--- a/promkit/src/preset/readline.rs
+++ b/promkit/src/preset/readline.rs
@@ -1,4 +1,4 @@
-use std::{cell::RefCell, collections::HashSet};
+use std::{cell::RefCell, collections::HashSet, io};
 
 use crate::{
     crossterm::style::{Attribute, Attributes, Color, ContentStyle},
@@ -34,6 +34,8 @@ pub struct Readline {
     validator: Option<ValidatorManager<str>>,
     /// State for displaying error messages based on input validation.
     error_message_state: text::State,
+    /// Writer to which promptkit write its contents
+    writer: Box<dyn io::Write>,
 }
 
 impl Default for Readline {
@@ -80,6 +82,7 @@ impl Default for Readline {
                     .attrs(Attributes::from(Attribute::Bold))
                     .build(),
             },
+            writer: Box::new(io::stdout()),
         }
     }
 }
@@ -172,6 +175,12 @@ impl Readline {
         self
     }
 
+    /// Sets writer.
+    pub fn writer<W: io::Write + 'static>(mut self, writer: W) -> Self {
+        self.writer = Box::new(writer);
+        self
+    }
+
     /// Initiates the prompt process,
     /// displaying the configured UI elements and handling user input.
     pub fn prompt(self) -> anyhow::Result<Prompt<render::Renderer>> {
@@ -185,6 +194,7 @@ impl Readline {
                 validator: self.validator,
                 error_message_snapshot: Snapshot::<text::State>::new(self.error_message_state),
             },
+            writer: self.writer,
         })
     }
 }
diff --git a/promkit/src/preset/tree.rs b/promkit/src/preset/tree.rs
index 0904ba85..99a067de 100644
--- a/promkit/src/preset/tree.rs
+++ b/promkit/src/preset/tree.rs
@@ -1,4 +1,4 @@
-use std::cell::RefCell;
+use std::{cell::RefCell, io};
 
 use crate::{
     crossterm::style::{Attribute, Attributes, Color, ContentStyle},
@@ -21,6 +21,8 @@ pub struct Tree {
     title_state: text::State,
     /// State for the tree itself.
     tree_state: tree::State,
+    /// Writer to which promptkit write its contents
+    writer: Box<dyn io::Write>,
 }
 
 impl Tree {
@@ -47,6 +49,7 @@ impl Tree {
                 lines: Default::default(),
                 indent: 2,
             },
+            writer: Box::new(io::stdout()),
         }
     }
 
@@ -103,6 +106,12 @@ impl Tree {
         self
     }
 
+    /// Sets writer.
+    pub fn writer<W: io::Write + 'static>(mut self, writer: W) -> Self {
+        self.writer = Box::new(writer);
+        self
+    }
+
     /// Displays the tree prompt and waits for user input.
     /// Returns a `Result` containing the `Prompt` result,
     /// which is a list of selected options.
@@ -113,6 +122,7 @@ impl Tree {
                 title_snapshot: Snapshot::<text::State>::new(self.title_state),
                 tree_snapshot: Snapshot::<tree::State>::new(self.tree_state),
             },
+            writer: self.writer,
         })
     }
 }
diff --git a/promkit/src/terminal.rs b/promkit/src/terminal.rs
index d15e0f2d..0b834e50 100644
--- a/promkit/src/terminal.rs
+++ b/promkit/src/terminal.rs
@@ -1,17 +1,27 @@
-use std::io::{self, Write};
+use std::io::Write;
 
 use crate::{
     crossterm::{cursor, style, terminal},
     pane::Pane,
 };
 
-pub struct Terminal {
+pub struct Terminal<'a, W: Write> {
     /// The current cursor position within the terminal.
     pub position: (u16, u16),
+    pub writer: &'a mut W,
 }
 
-impl Terminal {
-    pub fn start_session(panes: &[Pane]) -> anyhow::Result<Self> {
+impl<'a, W: Write> Terminal<'a, W> {
+    pub fn on_resize(&mut self) -> anyhow::Result<()> {
+        self.position = (0, 0);
+        crossterm::execute!(
+            self.writer,
+            crossterm::terminal::Clear(crossterm::terminal::ClearType::Purge),
+        )?;
+        Ok(())
+    }
+
+    pub fn start_session(panes: &[Pane], writer: &'a mut W) -> anyhow::Result<Self> {
         let position = cursor::position()?;
         let size = terminal::size()?;
 
@@ -23,9 +33,9 @@ impl Terminal {
         //    to ensure the next output starts correctly.
         if position.0 != 0 {
             if size.1 == position.1 + 1 {
-                crossterm::queue!(io::stdout(), terminal::ScrollUp(1))?;
+                crossterm::queue!(writer, terminal::ScrollUp(1))?;
             }
-            crossterm::queue!(io::stdout(), cursor::MoveToNextLine(1))?;
+            crossterm::queue!(writer, cursor::MoveToNextLine(1))?;
         }
 
         // Calculate the total number of rows required by all panes.
@@ -39,16 +49,17 @@ impl Terminal {
         // to maintain its relative position.
         if size.1 == position.1 + 1 {
             crossterm::queue!(
-                io::stdout(),
+                writer,
                 terminal::ScrollUp(lines as u16),
                 cursor::MoveToPreviousLine(lines as u16),
             )?;
         }
 
-        io::stdout().flush()?;
+        writer.flush()?;
 
         Ok(Self {
             position: cursor::position()?,
+            writer,
         })
     }
 
@@ -62,7 +73,7 @@ impl Terminal {
 
         if height < viewable_panes.len() as u16 {
             return crossterm::execute!(
-                io::stdout(),
+                self.writer,
                 terminal::Clear(terminal::ClearType::FromCursorDown),
                 style::Print("⚠️ Insufficient Space"),
             )
@@ -70,7 +81,7 @@ impl Terminal {
         }
 
         crossterm::queue!(
-            io::stdout(),
+            self.writer,
             cursor::MoveTo(self.position.0, self.position.1),
             terminal::Clear(terminal::ClearType::FromCursorDown),
         )?;
@@ -88,7 +99,7 @@ impl Terminal {
             );
             used += rows.len();
             for (j, row) in rows.iter().enumerate() {
-                crossterm::queue!(io::stdout(), style::Print(row.styled_display()))?;
+                crossterm::queue!(self.writer, style::Print(row.styled_display()))?;
 
                 current_cursor_y = current_cursor_y.saturating_sub(1);
 
@@ -96,14 +107,14 @@ impl Terminal {
                     || i != viewable_panes.len() - 1)
                     && current_cursor_y == 0
                 {
-                    crossterm::queue!(io::stdout(), terminal::ScrollUp(1))?;
+                    crossterm::queue!(self.writer, terminal::ScrollUp(1))?;
                     self.position.1 = self.position.1.saturating_sub(1);
                 }
 
-                crossterm::queue!(io::stdout(), cursor::MoveToNextLine(1))?;
+                crossterm::queue!(self.writer, cursor::MoveToNextLine(1))?;
             }
         }
-        io::stdout().flush()?;
+        self.writer.flush()?;
         Ok(())
     }
 }