diff --git a/api/src/card.rs b/api/src/card.rs
new file mode 100644
index 0000000..547dbab
--- /dev/null
+++ b/api/src/card.rs
@@ -0,0 +1,192 @@
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct Card(u8);
+
+impl Card {
+    // Constants for suits
+    pub const SPADES: u8 = 0;
+    pub const HEARTS: u8 = 1;
+    pub const DIAMONDS: u8 = 2;
+    pub const CLUBS: u8 = 3;
+
+    // Constants for ranks
+    pub const TWO: u8 = 2;
+    pub const THREE: u8 = 3;
+    pub const FOUR: u8 = 4;
+    pub const FIVE: u8 = 5;
+    pub const SIX: u8 = 6;
+    pub const SEVEN: u8 = 7;
+    pub const EIGHT: u8 = 8;
+    pub const NINE: u8 = 9;
+    pub const TEN: u8 = 10;
+    pub const JACK: u8 = 11;
+    pub const QUEEN: u8 = 12;
+    pub const KING: u8 = 13;
+    pub const ACE: u8 = 14;
+
+    // Special constants
+    pub const BAD_CARD: u8 = 255;
+    pub const NUM_SUITS: u8 = 4;
+    pub const NUM_RANKS: u8 = 13;
+    pub const NUM_CARDS: u8 = 52;
+
+    // Constructor for an empty/invalid card
+    pub fn new() -> Self {
+        Self(Self::BAD_CARD)
+    }
+
+    // Constructor from rank and suit
+    pub fn from_rank_suit(rank: u8, suit: u8) -> Self {
+        assert!(rank >= Self::TWO && rank <= Self::ACE, "Invalid rank");
+        assert!(suit < Self::NUM_SUITS, "Invalid suit");
+        Self((suit << 4) | (rank & 0xF))
+    }
+
+    // Constructor from index (0..51)
+    pub fn from_index(index: u8) -> Self {
+        assert!(index < Self::NUM_CARDS, "Invalid index");
+        let rank = (index % Self::NUM_RANKS) + Self::TWO;
+        let suit = index / Self::NUM_RANKS;
+        Self::from_rank_suit(rank, suit)
+    }
+
+    // Constructor from string (e.g., "As" for Ace of Spades)
+    pub fn from_string(s: &str) -> Self {
+        assert!(s.len() == 2, "Invalid card string");
+        let rank_char = s.chars().nth(0).unwrap();
+        let suit_char = s.chars().nth(1).unwrap();
+        let rank = Self::rank_from_char(rank_char);
+        let suit = Self::suit_from_char(suit_char);
+        Self::from_rank_suit(rank, suit)
+    }
+
+    // Get the rank of the card
+    pub fn rank(&self) -> u8 {
+        self.0 & 0xF
+    }
+
+    // Get the suit of the card
+    pub fn suit(&self) -> u8 {
+        (self.0 >> 4) & 0x3
+    }
+
+    // Get the index of the card (0..51)
+    pub fn index(&self) -> u8 {
+        (self.suit() * Self::NUM_RANKS) + (self.rank() - Self::TWO)
+    }
+
+    // Check if the card is valid
+    pub fn is_valid(&self) -> bool {
+        self.0 != Self::BAD_CARD
+    }
+
+    // Convert rank to character (e.g., 14 -> 'A')
+    pub fn rank_to_char(rank: u8) -> char {
+        match rank {
+            Self::TWO => '2',
+            Self::THREE => '3',
+            Self::FOUR => '4',
+            Self::FIVE => '5',
+            Self::SIX => '6',
+            Self::SEVEN => '7',
+            Self::EIGHT => '8',
+            Self::NINE => '9',
+            Self::TEN => 'T',
+            Self::JACK => 'J',
+            Self::QUEEN => 'Q',
+            Self::KING => 'K',
+            Self::ACE => 'A',
+            _ => panic!("Invalid rank"),
+        }
+    }
+
+    // Convert suit to character (e.g., 0 -> 's')
+    pub fn suit_to_char(suit: u8) -> char {
+        match suit {
+            Self::SPADES => 's',
+            Self::HEARTS => 'h',
+            Self::DIAMONDS => 'd',
+            Self::CLUBS => 'c',
+            _ => panic!("Invalid suit"),
+        }
+    }
+
+    // Convert rank character to rank (e.g., 'A' -> 14)
+    pub fn rank_from_char(rank_char: char) -> u8 {
+        match rank_char {
+            '2' => Self::TWO,
+            '3' => Self::THREE,
+            '4' => Self::FOUR,
+            '5' => Self::FIVE,
+            '6' => Self::SIX,
+            '7' => Self::SEVEN,
+            '8' => Self::EIGHT,
+            '9' => Self::NINE,
+            'T' => Self::TEN,
+            'J' => Self::JACK,
+            'Q' => Self::QUEEN,
+            'K' => Self::KING,
+            'A' => Self::ACE,
+            _ => panic!("Invalid rank character"),
+        }
+    }
+
+    // Convert suit character to suit (e.g., 's' -> 0)
+    pub fn suit_from_char(suit_char: char) -> u8 {
+        match suit_char {
+            's' => Self::SPADES,
+            'h' => Self::HEARTS,
+            'd' => Self::DIAMONDS,
+            'c' => Self::CLUBS,
+            _ => panic!("Invalid suit character"),
+        }
+    }
+}
+
+impl std::fmt::Display for Card {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        if !self.is_valid() {
+            write!(f, "Invalid Card")
+        } else {
+            let rank_char = Self::rank_to_char(self.rank());
+            let suit_char = Self::suit_to_char(self.suit());
+            write!(f, "{}{}", rank_char, suit_char)
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_card_creation() {
+        let card = Card::from_rank_suit(Card::ACE, Card::SPADES);
+        assert_eq!(card.rank(), Card::ACE);
+        assert_eq!(card.suit(), Card::SPADES);
+        assert_eq!(card.index(), 12); // Ace of Spades is index 12
+        assert!(card.is_valid());
+    }
+
+    #[test]
+    fn test_card_from_string() {
+        let card = Card::from_string("As");
+        assert_eq!(card.rank(), Card::ACE);
+        assert_eq!(card.suit(), Card::SPADES);
+        assert_eq!(card.to_string(), "As");
+    }
+
+    #[test]
+    fn test_card_from_index() {
+        let card = Card::from_index(0);
+        assert_eq!(card.rank(), Card::TWO);
+        assert_eq!(card.suit(), Card::SPADES);
+        assert_eq!(card.to_string(), "2s");
+    }
+
+    #[test]
+    fn test_invalid_card() {
+        let card = Card::new();
+        assert!(!card.is_valid());
+        assert_eq!(card.to_string(), "Invalid Card");
+    }
+}
diff --git a/api/src/lib.rs b/api/src/lib.rs
new file mode 100644
index 0000000..2e8b5ec
--- /dev/null
+++ b/api/src/lib.rs
@@ -0,0 +1 @@
+pub mod card;
\ No newline at end of file
diff --git a/api/tests/card_test.rs b/api/tests/card_test.rs
new file mode 100644
index 0000000..b09311a
--- /dev/null
+++ b/api/tests/card_test.rs
@@ -0,0 +1,7 @@
+use poker_api::card::Card;
+
+#[test]
+fn test_card_integration() {
+    let card = Card::from_string("As");
+    assert_eq!(card.to_string(), "As");
+}