diff --git a/src/tui/viewer.py b/src/tui/viewer.py
new file mode 100644
index 0000000..f53f3f7
--- /dev/null
+++ b/src/tui/viewer.py
@@ -0,0 +1,159 @@
+"""TUI viewer module for displaying data with syntax highlighting."""
+
+from typing import Any
+from rich.console import Console
+from rich.syntax import Syntax
+from rich.theme import Theme
+from rich.panel import Panel
+from rich.text import Text
+from rich.box import ROUNDED
+
+
+class DataViewer:
+    """Viewer for displaying data with syntax highlighting."""
+    
+    DEFAULT_THEMES = {
+        'default': 'rich',
+        'monokai': 'monokai',
+        'github-dark': 'github-dark',
+        'github-light': 'github-light',
+        'dracula': 'dracula',
+        'nord': 'nord',
+        'one-dark': 'one-dark',
+    }
+    
+    def __init__(self, theme: str = 'default', console: Console = None):
+        """Initialize the data viewer.
+        
+        Args:
+            theme: Syntax highlighting theme name
+            console: Rich Console instance
+        """
+        self.theme_name = theme
+        self.console = console or Console()
+        self.theme = self._load_theme(theme)
+    
+    def _load_theme(self, theme_name: str) -> Theme:
+        """Load a Rich theme.
+        
+        Args:
+            theme_name: Name of the theme
+            
+        Returns:
+            Rich Theme instance
+        """
+        theme_map = {
+            'default': None,
+            'monokai': Theme({'syntax.string': 'green', 'syntax.keyword': 'orange3'}),
+            'github-dark': Theme({'syntax.string': 'green', 'syntax.keyword': 'blue'}),
+            'github-light': Theme({'syntax.string': 'green', 'syntax.keyword': 'blue'}),
+            'dracula': Theme({'syntax.string': 'green', 'syntax.keyword': 'purple'}),
+            'nord': Theme({'syntax.string': 'green', 'syntax.keyword': 'blue'}),
+            'one-dark': Theme({'syntax.string': 'green', 'syntax.keyword': 'orange3'}),
+        }
+        return theme_map.get(theme_name)
+    
+    def get_language_for_format(self, format_name: str) -> str:
+        """Get syntax highlighting language for format.
+        
+        Args:
+            format_name: Data format name
+            
+        Returns:
+            Language identifier for Syntax highlighter
+        """
+        language_map = {
+            'json': 'json',
+            'yaml': 'yaml',
+            'toml': 'toml',
+            'csv': 'csv',
+        }
+        return language_map.get(format_name.lower(), 'text')
+    
+    def view(self, content: str, format_name: str, title: str = None) -> None:
+        """Display data with syntax highlighting.
+        
+        Args:
+            content: Data content to display
+            format_name: Format of the data
+            title: Optional title for the panel
+        """
+        language = self.get_language_for_format(format_name)
+        
+        syntax = Syntax(
+            content,
+            language,
+            theme=self.theme or 'default',
+            line_numbers=True,
+            word_wrap=True,
+            indent_guides=True,
+        )
+        
+        panel = Panel(
+            syntax,
+            title=title or f"Data ({format_name.upper()})",
+            box=ROUNDED,
+            expand=True,
+        )
+        
+        self.console.print(panel)
+    
+    def view_data(self, data: Any, format_name: str, title: str = None, indent: int = 2) -> None:
+        """Display data object with syntax highlighting.
+        
+        Args:
+            data: Data object to display
+            format_name: Format of the data
+            title: Optional title for the panel
+            indent: Indentation level for serialization
+        """
+        from src.converters import get_converter
+        
+        converter = get_converter(format_name)
+        content = converter.dumps(data, indent=indent)
+        self.view(content, format_name, title)
+    
+    def display_error(self, message: str, title: str = "Error") -> None:
+        """Display an error message.
+        
+        Args:
+            message: Error message to display
+            title: Title for the error panel
+        """
+        text = Text(message, style='red bold')
+        panel = Panel(text, title=title, box=ROUNDED, style='red')
+        self.console.print(panel)
+    
+    def display_success(self, message: str, title: str = "Success") -> None:
+        """Display a success message.
+        
+        Args:
+            message: Success message to display
+            title: Title for the success panel
+        """
+        text = Text(message, style='green bold')
+        panel = Panel(text, title=title, box=ROUNDED, style='green')
+        self.console.print(panel)
+    
+    def display_validation_result(self, result) -> None:
+        """Display validation result.
+        
+        Args:
+            result: ValidationResult object
+        """
+        if result.valid:
+            self.display_success(f"Valid {result.format_type.upper()} file", "Validation")
+        else:
+            error_text = Text()
+            for error in result.errors:
+                if error.line and error.column:
+                    error_text.append(f"Line {error.line}, Column {error.column}: ", style='yellow')
+                error_text.append(f"{error.message}\n", style='red')
+            
+            panel = Panel(
+                error_text,
+                title="Validation Errors",
+                box=ROUNDED,
+                style='red'
+            )
+            self.console.print(panel)