diff --git a/nssa/test_program_methods/guest/src/bin/pool.rs b/nssa/test_program_methods/guest/src/bin/pool.rs
new file mode 100644
index 0000000..d720fbf
--- /dev/null
+++ b/nssa/test_program_methods/guest/src/bin/pool.rs
@@ -0,0 +1,317 @@
+use nssa_core::{
+    account::{Account, AccountId, AccountWithMetadata, Data},
+    program::{ProgramInput, read_nssa_inputs, write_nssa_outputs},
+};
+
+// The token program has two functions:
+// 1. New token definition.
+//    Arguments to this function are:
+//      * Two **default** accounts: [definition_account, holding_account].
+//        The first default account will be initialized with the token definition account values. The second account will
+//        be initialized to a token holding account for the new token, holding the entire total supply.
+//      * An instruction data of 23-bytes, indicating the total supply and the token name, with
+//        the following layout:
+//        [0x00 || total_supply (little-endian 16 bytes) || name (6 bytes)]
+//        The name cannot be equal to [0x00, 0x00, 0x00, 0x00, 0x00, 0x00]
+// 2. Token transfer
+//    Arguments to this function are:
+//      * Two accounts: [sender_account, recipient_account].
+//      * An instruction data byte string of length 23, indicating the total supply with the following layout
+//        [0x01 || amount (little-endian 16 bytes) || 0x00 || 0x00 || 0x00 || 0x00 || 0x00 || 0x00].
+
+
+//TODO: pool should have 2 tokens
+
+
+//TODO: correct these values
+const TOKEN_DEFINITION_TYPE: u8 = 0;
+const POOL_DEFINITION_DATA_SIZE: usize = 19;
+
+const TOKEN_HOLDING_TYPE: u8 = 1;
+const TOKEN_HOLDING_DATA_SIZE: usize = 49;
+
+struct PoolDefinition{
+    account_type: u8,
+    name_pool: [u8; 6], //TODO: unsure
+    name_token_a: [u8; 6], //TODO: specifies token A
+    name_token_b: [u8; 6], //TODO: specifies token B
+}
+
+struct PoolHolding {
+    account_type: u8,
+    definition_pool_id: AccountId,
+    definition_token_a_id: AccountId,
+    definition_token_b_id: AccountId,
+    definition_token_lp_id: AccountId,
+}
+
+
+impl PoolDefinition {
+    fn into_data(self) -> Vec<u8> {
+        let mut bytes = [0; POOL_DEFINITION_DATA_SIZE];
+        bytes[0] = self.account_type;
+        bytes[1..7].copy_from_slice(&self.name_pool);
+        bytes[7..13].copy_from_slice(&self.name_token_a);
+        bytes[13..].copy_from_slice(&self.name_token_b);
+        bytes.into();
+    }
+}
+
+impl PoolHolding {
+    fn new(definition_pool_id: &AccountId,
+            definition_token_a_id: &AccountId,
+            definition_token_b_id: &AccountId,
+            definition_token_lp_id: &AccountId,
+            ) -> Self {
+        Self {
+            account_type: TOKEN_HOLDING_TYPE, //TODO
+            definition_pool_id: definition_pool_id.clone(),
+            definition_token_a_id: definition_token_a_id.clone(),
+            definition_token_b_id: definition_token_b_id.clone(),
+            definition_token_lp_id: definition_token_lp_id.clone(),
+        }
+    }
+
+    fn parse(data: &[u8]) -> Option<Self> {
+        if data.len() != TOKEN_HOLDING_DATA_SIZE || data[0] != TOKEN_HOLDING_TYPE {
+            None
+        } else {
+            let account_type = data[0];
+            let definition_pool_id = AccountId::new(data[1..33].try_into().unwrap());
+            let definition_token_a_id = AccountId::new(data[33..65].try_into().unwrap());
+            let definition_token_b_id = AccountId::new(data[65..97].try_into().unwrap());
+            let definition_token_lp_id = AccountId::new(data[97..129]);
+            Some(Self {
+                definition_pool_id,
+                definition_token_a,
+                definition_token_b,
+                definition_token_lp_id,
+            })
+        }
+    }
+
+    fn into_data(self) -> Data {
+        let mut bytes = [0; TOKEN_HOLDING_DATA_SIZE];
+        bytes[0] = self.account_type;
+        bytes[1..33].copy_from_slice(&self.definition_pool_id.to_bytes());
+        bytes[33..65].copy_from_slice(&self.definition_token_a_id.to_bytes());
+        bytes[65..97].copy_from_slice(&self.definition_token_b_id.to_bytes());
+        bytes[97..].copy_from_slice(&self.definition_token_lp_id.to_bytes());
+        bytes.into()
+    }
+}
+
+
+fn initialize_pool(pre_state: &[AccountWithMetadata], balance_in: [u128]) {
+    //Pool accounts: pool itself, and its 2 vaults and LP token
+    //2 accounts for funding tokens
+    //initial funder's LP account
+    if pre_states.len() != 7 {
+        panic!("Invalid number of input account")
+    }
+
+    if balance_in.len() != 2 {
+        panic!("Invalid number of balance")
+    }
+
+    let mut pool = pre_state[0];
+    let mut vault_a = pre_state[1];
+    let mut vault_b = pre_state[2];
+    let mut pool_lp = pre_state[3];
+    let mut fund_a = pre_state[4];
+    let mut fund_b = pre_state[5];
+    let mut user_lp = pre_state[6];
+
+    if pool.account != Account::default() || !pool.is_authorized {
+        return;
+    }
+
+    if vault_a.account != Account::default() || !vault_a.is_authorized {
+        return;
+    }
+
+    if pool_b.account != Account::default() || !vault_b.is_authorized {
+        return;
+    }
+
+    if pool_lp.account != Account::default() || !pool_lp.account.is_authorized {
+        return;
+    }
+    
+    if !fund_a.is_authorized || !fund_b.is_authorized {
+        return;
+    }
+
+    if user_lp.account != Account::default() || !user_lp.account.is_authorized {
+        return;
+    }
+        
+
+    let balance_a = balance_in[0];
+    let balance_b = balance_in[1];
+
+    // Prevents pool constant coefficient (k) from being 0.
+    assert!(balance_a > 0);
+    assert!(balance_b > 0);
+
+    // Verify token_a and token_b are different
+    token_a_id = fund_a.account.data.parse().definition_id;
+    token_b_id = fund_b.account.data.parse().definition_id;
+    assert!(token_a_id != token_b_id);
+
+    // 1. Account verification
+    //TODO: check a pool for (tokenA, tokenB) does not already exist?
+
+        
+    // 2. Initialize stake
+    let pool_data = PoolDefinition::new(pool_id,
+                    token_a_id,
+                    token_b_id).into_data();
+
+        
+    // 3. LP token minting calculations
+    //TODO
+
+    // 4. Cross program calls
+    //TODO
+}
+
+fn swap(pre_states: &[AccountWithMetadata], balance_in: [u128], min_amount_out: u128) {
+    //Does not require pool's LP account
+    if pre_states.len() != 5 {
+        panic!("Invalid number of input accounts");
+    }
+    let pool = &pre_states[0];
+    let vault_a = &pre_states[1];
+    let vault_b = &pre_states[2];
+    let user_a = &pre_states[3];
+    let user_b = &pre_states[4];
+
+    if balance_in.len() != 2 {
+        panic!("Invalid number of input balances");
+    }
+
+    //TODO: return here
+    let mut pool_holding =
+        PoolHolding::parse(&pool.account.data).expect("Invalid pool data");
+
+    //TODO: return here
+    //TODO: a new account must be minted for the recipient regardless.
+    //So, we should receive 3 accounts for pre_state.
+    //TODO: fix sender_holding
+    let mut user_holding = if recipient.account == Account::default() {
+        TokenHolding::new(&sender_holding.definition_id);
+    };
+
+
+    // 1. Identify swap direction (a -> b or b -> a)
+    // Exactly one should be 0.
+    let in_a = balance_in[0];
+    let in_b = balance_in[1];
+    assert!( in_a == 0 || in_b == 0);
+    assert!( in_a > 0 || in_b > 0);
+    let a_to_b: bool = if in_a > 0 { true } else { false };
+
+    // 2. fetch pool reserves
+    assert!(vault_a.account.balance > 0);
+    assert!(vault_b.account.balance > 0);
+
+    // 3. Compute output amount
+    // Note: no fees
+    // Compute pool's exchange constant
+    let k = vault_a.account.balance * vault_b.account.balance;
+    let net_in_a = in_a;
+    let net_in_b = in_b;
+    let amount_out_a = if a_to_b { (vault_b.balance * net_in_b)/(vault_a.account.balance + net_in_a)}
+                    else { 0 };
+    let amount_out_b = if a_to_b { 0 }
+                else {
+                    (vault_a.account.balance * net_in_a)/(vault_b.account.balance + net_in_b) };                    
+
+    // 4. Slippage check
+    if a_to_b {
+        assert!(amount_out_a > min_amount_out); }
+    else{
+        assert!(amount_out_b > min_amount_out); }
+
+    //TODO Note to self: step 5 unnecessary (update reserves)
+
+    // 6. Transfer tokens (Cross call)
+    //TODO
+
+    // 7. Result
+    //TODO
+
+}
+    
+
+
+fn add_liquidity(pre_state: &[AccountWithMetadata], max_balance_in: [u128], main_token: AccountId) {
+    if pre_states.len() != 7 {
+       panic!("Invalid number of input accounts");
+    }
+
+    let pool = &pre_states[0];
+    let vault_a = &pre_states[1];
+    let vault_b = &pre_states[2];
+    let pool_lp = &pre_states[3];
+    let user_a = &pre_states[4];
+    let user_b = &pre_states[5];
+    let user_lp = &pre_state[6];
+
+    if balance_in.len() != 2 {
+        panic!("Invalid number of input balances");
+    }
+
+    //TODO: add authorization checks if need be;
+    //might be redundant
+
+    max_amount_a = balance_in[0];
+    max_amount_b = balance_in[1];
+
+    // 2. Determine deposit amounts
+    pool_data = pool.account.data.parse();
+    let mut actual_amount_a = 0;
+    let mut actual_amount_b = 0;
+
+    if main_token == pool_data.definition_token_a {
+        actual_amount_a = max_amount_a;
+        actual_amount_b = (vault_b.account.balance/vault_a.account.balance)*actual_amount_a;
+    } else if main_token == pool_data.definition_token_b {
+        actual_amount_b = max_amount_b;
+        actual_amount_a = (vault_a.account.balance/vault_b.account.balance)*actual_amount_b;
+    } else {
+        return; //main token does not match with vaults.
+    }
+
+    // 3. Validate amounts
+    assert!(user_a.account.balance >= actual_amount_a && actual_amount_a > 0);
+    assert!(user_b.account.balance >= actual_amount_b && actual_amount_b > 0)
+
+    // 4. Calculate LP to mint
+    //TODO
+}
+
+
+
+
+fn remove_liquidity(pre_state: &[AccountWithMetadata], max_balance_in: [u128], main_token: AccountId) {
+    if pre_states.len() != 7 {
+       panic!("Invalid number of input accounts");
+    }
+
+    let pool = &pre_states[0];
+    let vault_a = &pre_states[1];
+    let vault_b = &pre_states[2];
+    let pool_lp = &pre_states[3];
+    let user_a = &pre_states[4];
+    let user_b = &pre_states[5];
+    let user_lp = &pre_states[6];
+
+    if balance_in.len() != 2 {
+        panic!("Invalid number of input balances");
+    }
+
+    assert!(user_lp.account.balance)
+    //TODO
+}
\ No newline at end of file