diff --git a/Cargo.toml b/Cargo.toml
index 62c3807..3f6057e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "tycho-execution"
-version = "1.0.0"
+version = "0.1.0"
 edition = "2021"
 
 [dependencies]
diff --git a/src/encoding/approvals_manager.rs b/src/encoding/approvals_manager.rs
new file mode 100644
index 0000000..fb37bfb
--- /dev/null
+++ b/src/encoding/approvals_manager.rs
@@ -0,0 +1,51 @@
+use std::{env, sync::Arc};
+
+use alloy::{
+    providers::{Provider, ProviderBuilder, RootProvider},
+    transports::BoxTransport,
+};
+use alloy_primitives::{Address, U256};
+use dotenv::dotenv;
+use tycho_core::Bytes;
+
+pub struct TokenApprovalsManager {
+    client: Arc<RootProvider<BoxTransport>>,
+}
+
+impl TokenApprovalsManager {
+    pub fn new(client: Arc<RootProvider<BoxTransport>>) -> Self {
+        Self { client }
+    }
+
+    pub async fn approval_needed(
+        &self,
+        token: Bytes,
+        spender_address: Address,
+        router_address: Address,
+    ) -> bool {
+        // should be something like
+        // let allowance = self
+        //     .client
+        //     .call(token, "allowance(address,address)(uint256)", (router_address, spender_address))
+        //     .await;
+        //
+        // allowance == U256::ZERO // If allowance is 0, approval is needed
+        todo!()
+    }
+}
+
+pub fn get_client() -> Arc<RootProvider<BoxTransport>> {
+    dotenv().ok();
+    let eth_rpc_url = env::var("ETH_RPC_URL").expect("Missing ETH_RPC_URL in environment");
+    let runtime = tokio::runtime::Handle::try_current()
+        .is_err()
+        .then(|| tokio::runtime::Runtime::new().unwrap())
+        .unwrap();
+    let client = runtime.block_on(async {
+        ProviderBuilder::new()
+            .on_builtin(&eth_rpc_url)
+            .await
+            .unwrap()
+    });
+    Arc::new(client)
+}
diff --git a/src/encoding/mod.rs b/src/encoding/mod.rs
new file mode 100644
index 0000000..538b893
--- /dev/null
+++ b/src/encoding/mod.rs
@@ -0,0 +1,6 @@
+mod approvals_manager;
+mod models;
+mod router_encoder;
+mod strategy_encoder;
+mod swap_encoder;
+mod utils;
diff --git a/src/encoding/models.rs b/src/encoding/models.rs
new file mode 100644
index 0000000..7076d49
--- /dev/null
+++ b/src/encoding/models.rs
@@ -0,0 +1,61 @@
+use alloy_primitives::Address;
+use num_bigint::BigUint;
+use tycho_core::{dto::ProtocolComponent, Bytes};
+
+pub struct Solution {
+    pub orders: Vec<Order>,
+    // if not set, then the Propeller Router will be used
+    pub router_address: Option<Address>,
+}
+
+pub struct Order {
+    /// True if the order is an exact output order.
+    pub exact_out: bool,
+    /// The token being sold (exact in) or bought (exact out).
+    given_token: Bytes,
+    /// Amount of the given token.
+    pub given_amount: BigUint,
+    /// The token being bought (exact in) or sold (exact out).
+    checked_token: Bytes,
+    /// Amount of the checked token.
+    checked_amount: BigUint,
+    /// Address of the sender.
+    sender: Bytes,
+    /// Address of the receiver.
+    pub receiver: Bytes,
+    /// List of swaps to fulfill the order.
+    pub swaps: Vec<Swap>,
+    /// Whether to include router calldata (true) or just swap data (false).
+    add_router_calldata: bool,
+
+    pub slippage: f64,
+    pub min_checked_amount: Option<BigUint>,
+}
+
+#[derive(Clone)]
+pub struct Swap {
+    /// Protocol component from tycho indexer
+    pub component: ProtocolComponent,
+    /// Token being input into the pool.
+    pub token_in: Bytes,
+    /// Token being output from the pool.
+    pub token_out: Bytes,
+    /// Fraction of the amount to be swapped in this operation.
+    pub split: f64,
+}
+
+// maybe this struct is useful - keeping it here for now (maybe we could collapse this with another
+// struct)
+pub struct EncodingContext {
+    pub receiver: Address,
+    pub exact_out: bool,
+    pub router_address: Address,
+}
+
+pub enum ActionType {
+    SingleExactIn = 1,
+    SingleExactOut = 2,
+    SequentialExactIn = 3,
+    SequentialExactOut = 4,
+    SplitIn = 5,
+}
diff --git a/src/encoding/router_encoder.rs b/src/encoding/router_encoder.rs
new file mode 100644
index 0000000..958c140
--- /dev/null
+++ b/src/encoding/router_encoder.rs
@@ -0,0 +1,61 @@
+use crate::encoding::models::{Order, Solution};
+use crate::encoding::strategy_encoder::{
+    SequentialExactInStrategyEncoder, SingleSwapStrategyEncoder, SlipSwapStrategyEncoder,
+    StrategyEncoder,
+};
+use crate::encoding::utils::{encode_input, ple_encode};
+use alloy_primitives::Address;
+use alloy_sol_types::SolValue;
+use anyhow::Error;
+use std::env;
+use std::str::FromStr;
+
+struct RouterEncoder {
+    router_address: Address,
+}
+
+impl RouterEncoder {
+    pub fn new() -> Self {
+        let router_address = Address::from_str(
+            &env::var("ROUTER_ADDRESS").expect("Missing ROUTER_ADDRESS in environment"),
+        )
+        .expect("Invalid ROUTER_ADDRESS");
+        Self { router_address }
+    }
+
+    pub fn encode_router_calldata(&self, solution: Solution) -> Result<Vec<u8>, Error> {
+        let mut calldata_list: Vec<Vec<u8>> = Vec::new();
+        let encode_for_batch_execute = solution.orders.len() > 1;
+        for order in solution.orders {
+            let strategy = self.get_strategy(&order);
+            // TODO: handle native action??
+
+            let contract_interaction = strategy.encode_strategy(
+                order,
+                if solution.router_address.is_some() {
+                    solution.router_address.unwrap()
+                } else {
+                    self.router_address
+                },
+                encode_for_batch_execute,
+            )?;
+            calldata_list.push(contract_interaction);
+        }
+        if encode_for_batch_execute {
+            let args = (false, ple_encode(calldata_list));
+            Ok(encode_input("batchExecute(bytes)", args.abi_encode()))
+        } else {
+            Ok(calldata_list[0].clone())
+        }
+    }
+
+    fn get_strategy(&self, order: &Order) -> &dyn StrategyEncoder {
+        if order.swaps.len() == 1 {
+            &SingleSwapStrategyEncoder {}
+        } else if order.swaps.iter().all(|s| s.split == 0.0) {
+            &SequentialExactInStrategyEncoder {}
+        } else {
+            &SlipSwapStrategyEncoder {}
+        }
+    }
+}
diff --git a/src/encoding/strategy_encoder.rs b/src/encoding/strategy_encoder.rs
new file mode 100644
index 0000000..dafd1c4
--- /dev/null
+++ b/src/encoding/strategy_encoder.rs
@@ -0,0 +1,130 @@
+use alloy_primitives::Address;
+use alloy_sol_types::SolValue;
+use anyhow::Error;
+use num_bigint::BigUint;
+use std::cmp::min;
+
+use crate::encoding::models::{ActionType, EncodingContext, Order};
+use crate::encoding::swap_encoder::{get_swap_encoder, get_swap_executor_address};
+use crate::encoding::utils::{biguint_to_u256, bytes_to_address, encode_input, ple_encode};
+
+pub trait StrategyEncoder {
+    fn encode_strategy(
+        &self,
+        to_encode: Order,
+        router_address: Address,
+        encode_for_batch_execute: bool,
+    ) -> Result<Vec<u8>, Error>;
+
+    fn encode_protocol_header(
+        &self,
+        protocol_data: Vec<u8>,
+        protocol_system: String,
+        // Token indices, split, and token inclusion are only used for split swaps
+        token_in: u16,
+        token_out: u16,
+        split: u16, // not sure what should be the type of this :/
+    ) -> Vec<u8> {
+        let executor_address = get_swap_executor_address(&protocol_system);
+        let args = (executor_address, token_in, token_out, split, protocol_data);
+        args.abi_encode()
+    }
+}
+
+pub struct SingleSwapStrategyEncoder {}
+
+impl StrategyEncoder for SingleSwapStrategyEncoder {
+    fn encode_strategy(
+        &self,
+        order: Order,
+        router_address: Address,
+        encode_for_batch_execute: bool,
+    ) -> Result<Vec<u8>, Error> {
+        todo!()
+    }
+}
+
+pub struct SequentialExactInStrategyEncoder {}
+
+impl StrategyEncoder for SequentialExactInStrategyEncoder {
+    fn encode_strategy(
+        &self,
+        order: Order,
+        router_address: Address,
+        encode_for_batch_execute: bool,
+    ) -> Result<Vec<u8>, Error> {
+        let one_hundred = BigUint::from(100u32);
+        let slippage_percent = BigUint::from((order.slippage * 100.0) as u32);
+        let multiplier = &one_hundred - slippage_percent;
+        let slippage_buy_amount = (&order.given_amount * multiplier) / one_hundred;
+
+        let min_checked_amount = if order.min_checked_amount.is_some() {
+            min(order.min_checked_amount.unwrap(), slippage_buy_amount)
+        } else {
+            slippage_buy_amount
+        };
+        let mut swaps = vec![];
+        for (index, swap) in order.swaps.iter().enumerate() {
+            let is_last = index == order.swaps.len() - 1;
+            let protocol_system = swap.component.protocol_system.clone();
+            let swap_encoder = get_swap_encoder(&protocol_system);
+            let receiver = if is_last {
+                bytes_to_address(&order.receiver)?
+            } else {
+                router_address
+            };
+            let encoding_context = EncodingContext {
+                receiver,
+                exact_out: order.exact_out,
+                router_address,
+            };
+            let protocol_data = swap_encoder.encode_swap(swap.clone(), encoding_context)?;
+            let swap_data = self.encode_protocol_header(protocol_data, protocol_system, 0, 0, 0);
+            swaps.push(swap_data);
+        }
+        let (selector, action_type) = if order.exact_out {
+            (
+                "sequentialExactOut(uint256, uint256, bytes[])",
+                ActionType::SequentialExactOut,
+            )
+        } else {
+            (
+                "sequentialExactIn(uint256, uint256, bytes[])",
+                ActionType::SequentialExactIn,
+            )
+        };
+        let encoded_swaps = ple_encode(swaps);
+        if encode_for_batch_execute {
+            let args = (
+                action_type as u16,
+                biguint_to_u256(&order.given_amount),
+                biguint_to_u256(&min_checked_amount),
+                encoded_swaps,
+            );
+            Ok(args.abi_encode())
+        } else {
+            Ok(encode_input(
+                selector,
+                (
+                    biguint_to_u256(&order.given_amount),
+                    biguint_to_u256(&min_checked_amount),
+                    encoded_swaps,
+                )
+                    .abi_encode(),
+            ))
+        }
+    }
+}
+
+pub struct SlipSwapStrategyEncoder {}
+
+impl StrategyEncoder for SlipSwapStrategyEncoder {
+    fn encode_strategy(
+        &self,
+        order: Order,
+        router_address: Address,
+        encode_for_batch_execute: bool,
+    ) -> Result<Vec<u8>, Error> {
+        todo!()
+    }
+}
diff --git a/src/encoding/swap_encoder.rs b/src/encoding/swap_encoder.rs
new file mode 100644
index 0000000..0c025d5
--- /dev/null
+++ b/src/encoding/swap_encoder.rs
@@ -0,0 +1,86 @@
+use alloy_primitives::Address;
+use alloy_sol_types::SolValue;
+use anyhow::Error;
+use std::str::FromStr;
+
+use crate::encoding::utils::bytes_to_address;
+use crate::encoding::{
+    approvals_manager::{get_client, TokenApprovalsManager},
+    models::{EncodingContext, Swap},
+};
+
+pub trait SwapEncoder: Sync + Send {
+    fn encode_swap(&self, swap: Swap, encoding_context: EncodingContext) -> Result<Vec<u8>, Error>;
+}
+
+struct UniswapV2SwapEncoder {}
+
+impl SwapEncoder for UniswapV2SwapEncoder {
+    fn encode_swap(&self, swap: Swap, encoding_context: EncodingContext) -> Result<Vec<u8>, Error> {
+        todo!()
+    }
+}
+
+struct BalancerV2SwapEncoder {
+    vault_address: Option<Address>,
+}
+
+impl BalancerV2SwapEncoder {
+    pub fn new() -> Self {
+        Self {
+            vault_address: Some(
+                Address::from_str("0xba12222222228d8ba445958a75a0704d566bf2c8")
+                    .expect("Invalid string for balancer vault address"),
+            ),
+        }
+    }
+}
+
+impl SwapEncoder for BalancerV2SwapEncoder {
+    fn encode_swap(&self, swap: Swap, encoding_context: EncodingContext) -> Result<Vec<u8>, Error> {
+        let client = get_client();
+        let token_approvals_manager = TokenApprovalsManager::new(client);
+        let runtime = tokio::runtime::Handle::try_current()
+            .is_err()
+            .then(|| tokio::runtime::Runtime::new().unwrap())
+            .unwrap();
+        let approval_needed = runtime.block_on(async {
+            token_approvals_manager
+                .approval_needed(
+                    swap.token_in.clone(),
+                    encoding_context.router_address,
+                    self.vault_address.unwrap(),
+                )
+                .await
+        });
+        // should we return gas estimation here too?? if there is an approval needed, gas will be
+        // higher.
+        let args = (
+            bytes_to_address(&swap.token_in)?,
+            bytes_to_address(&swap.token_out)?,
+            swap.component.id,
+            encoding_context.receiver,
+            encoding_context.exact_out,
+            approval_needed,
+        );
+        Ok(args.abi_encode())
+    }
+}
+
+pub fn get_swap_encoder(protocol_system: &str) -> Box<dyn SwapEncoder> {
+    match protocol_system {
+        "uniswap_v2" => Box::new(UniswapV2SwapEncoder {}),
+        "vm:balancer_v2" => Box::new(BalancerV2SwapEncoder::new()),
+        _ => panic!("Unknown protocol system: {}", protocol_system),
+    }
+}
+
+pub fn get_swap_executor_address(protocol_system: &str) -> Address {
+    match protocol_system {
+        "uniswap_v2" => Address::from_str("0x5C2F5a71f67c01775180ADc06909288B4C329308")
+            .expect("Invalid address"),
+        "vm:balancer_v2" => Address::from_str("0x543778987b293C7E8Cf0722BB2e935ba6f4068D4")
+            .expect("Invalid address"),
+        _ => panic!("Unknown protocol system: {}", protocol_system),
+    }
+}
diff --git a/src/encoding/utils.rs b/src/encoding/utils.rs
new file mode 100644
index 0000000..a2c9683
--- /dev/null
+++ b/src/encoding/utils.rs
@@ -0,0 +1,56 @@
+use alloy_primitives::{Address, Keccak256, U256};
+use alloy_sol_types::SolValue;
+use anyhow::Error;
+use num_bigint::BigUint;
+use tycho_core::Bytes;
+
+/// Safely converts a `Bytes` object to an `Address` object.
+///
+/// Checks the length of the `Bytes` before attempting to convert, and returns a `SimulationError`
+/// if not 20 bytes long.
+pub fn bytes_to_address(address: &Bytes) -> Result<Address, Error> {
+    if address.len() == 20 {
+        Ok(Address::from_slice(address))
+    } else {
+        Err(anyhow::format_err!(
+            "Invalid ERC20 token address: {:?}",
+            address
+        ))
+    }
+}
+pub fn biguint_to_u256(value: &BigUint) -> U256 {
+    let bytes = value.to_bytes_be();
+    U256::from_be_slice(&bytes)
+}
+
+pub fn ple_encode(action_data_array: Vec<Vec<u8>>) -> Vec<u8> {
+    let mut encoded_action_data: Vec<u8> = Vec::new();
+
+    for action_data in action_data_array {
+        let args = (encoded_action_data, action_data.len() as u16, action_data);
+        encoded_action_data = args.abi_encode();
+    }
+
+    encoded_action_data
+}
+
+pub fn encode_input(selector: &str, mut encoded_args: Vec<u8>) -> Vec<u8> {
+    let mut hasher = Keccak256::new();
+    hasher.update(selector.as_bytes());
+    let selector_bytes = &hasher.finalize()[..4];
+    let mut call_data = selector_bytes.to_vec();
+    // Remove extra prefix if present (32 bytes for dynamic data)
+    // Alloy encoding is including a prefix for dynamic data indicating the offset or length
+    // but at this point we don't want that
+    if encoded_args.len() > 32
+        && encoded_args[..32]
+            == [0u8; 31]
+                .into_iter()
+                .chain([32].to_vec())
+                .collect::<Vec<u8>>()
+    {
+        encoded_args = encoded_args[32..].to_vec();
+    }
+    call_data.extend(encoded_args);
+    call_data
+}
diff --git a/src/lib.rs b/src/lib.rs
index 5512a6a..b8120c4 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,12 +1 @@
-#[allow(dead_code)]
-fn main() {
-    println!("Hello, world!");
-}
-
-#[cfg(test)]
-mod tests {
-    #[test]
-    fn it_works() {
-        assert_eq!(2 + 2, 4);
-    }
-}
+mod encoding;
\ No newline at end of file