diff --git a/envschema/validators.py b/envschema/validators.py
new file mode 100644
index 0000000..65afcbf
--- /dev/null
+++ b/envschema/validators.py
@@ -0,0 +1,153 @@
+"""Type validators for environment variable values."""
+
+import re
+from typing import Optional
+
+from envschema.schema import EnvVarType
+
+
+class ValidationError:
+    """Represents a validation error."""
+
+    def __init__(self, message: str, value: Optional[str] = None):
+        self.message = message
+        self.value = value
+
+    def __str__(self) -> str:
+        if self.value is not None:
+            return f"{self.message} (got: {self.value!r})"
+        return self.message
+
+
+class StringValidator:
+    """Validator for string type - always passes."""
+
+    @staticmethod
+    def validate(value: Optional[str]) -> tuple[bool, Optional[ValidationError]]:
+        if value is None:
+            return True, None
+        return True, None
+
+
+class IntegerValidator:
+    """Validator for integer type."""
+
+    @staticmethod
+    def validate(value: Optional[str]) -> tuple[bool, Optional[ValidationError]]:
+        if value is None:
+            return True, None
+        try:
+            int(value)
+            return True, None
+        except ValueError:
+            return False, ValidationError(
+                f"Invalid integer value",
+                value=value
+            )
+
+
+class BooleanValidator:
+    """Validator for boolean type."""
+
+    TRUE_VALUES = {"true", "1", "yes", "on"}
+    FALSE_VALUES = {"false", "0", "no", "off"}
+
+    @staticmethod
+    def validate(value: Optional[str]) -> tuple[bool, Optional[ValidationError]]:
+        if value is None:
+            return True, None
+        value_lower = value.lower().strip()
+        if value_lower in BooleanValidator.TRUE_VALUES:
+            return True, None
+        if value_lower in BooleanValidator.FALSE_VALUES:
+            return True, None
+        return False, ValidationError(
+            f"Invalid boolean value (expected: true, false, 1, 0, yes, no, on, off)",
+            value=value
+        )
+
+
+class ListValidator:
+    """Validator for list type (comma-separated values)."""
+
+    @staticmethod
+    def validate(value: Optional[str]) -> tuple[bool, Optional[ValidationError]]:
+        if value is None:
+            return True, None
+        if "," in value:
+            return True, None
+        return False, ValidationError(
+            f"Invalid list value (expected comma-separated values)",
+            value=value
+        )
+
+    @staticmethod
+    def parse(value: str) -> list[str]:
+        """Parse a comma-separated string into a list.
+
+        Args:
+            value: Comma-separated string.
+
+        Returns:
+            List of values.
+        """
+        return [item.strip() for item in value.split(",") if item.strip()]
+
+
+class PatternValidator:
+    """Validator for pattern/regex validation."""
+
+    @staticmethod
+    def validate(value: Optional[str], pattern: str) -> tuple[bool, Optional[ValidationError]]:
+        if value is None:
+            return True, None
+        try:
+            if re.match(pattern, value):
+                return True, None
+            return False, ValidationError(
+                f"Value does not match pattern: {pattern}",
+                value=value
+            )
+        except re.error:
+            return False, ValidationError(
+                f"Invalid regex pattern: {pattern}",
+                value=value
+            )
+
+
+def get_validator(var_type: EnvVarType):
+    """Get the validator class for a given type.
+
+    Args:
+        var_type: The environment variable type.
+
+    Returns:
+        Validator class.
+    """
+    validators = {
+        EnvVarType.STRING: StringValidator,
+        EnvVarType.INTEGER: IntegerValidator,
+        EnvVarType.BOOLEAN: BooleanValidator,
+        EnvVarType.LIST: ListValidator,
+    }
+    return validators.get(var_type, StringValidator)
+
+
+def validate_value(value: Optional[str], var_type: EnvVarType, pattern: Optional[str] = None) -> tuple[bool, Optional[ValidationError]]:
+    """Validate a value against a type and optional pattern.
+
+    Args:
+        value: The value to validate.
+        var_type: The expected type.
+        pattern: Optional regex pattern.
+
+    Returns:
+        Tuple of (is_valid, error).
+    """
+    validator = get_validator(var_type)
+    is_valid, error = validator.validate(value)
+
+    if is_valid and pattern and value is not None:
+        is_valid, error = PatternValidator.validate(value, pattern)
+
+    return is_valid, error
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