Limit Order Events

Parse limit order events from program logs using Borsh deserialization.

You can listen to limit order events by parsing through the program logs for emitted data. Events are Borsh-serialized and emitted in program logs for every order lifecycle operation.

---

Event structure

#[repr(C)]
#[derive(Clone, Copy, Debug, PartialEq, Eq, BorshDeserialize, BorshSerialize)]
pub struct LimitOrderEvent {
    /// Event discriminator, used to identify the event type
    /// Create - 1, Take - 2, Cancel - 3, Modify - 4, Withdraw - 5, CloseExpired - 6
    pub discriminator: u8,
    /// Instruction that triggered the event
    pub instruction: u8,
    /// The status of the order
    pub status: u8,
    /// Unique identifier for the order, used to differentiate orders for same
    /// (owner, input_mint, output_mint) tuple
    pub id: u8,
    /// The public key of the order
    pub maker: Pubkey,
    /// The mint of the input token
    pub input_mint: Pubkey,
    /// The mint of the output token
    pub output_mint: Pubkey,
    /// The slot at which the event was emitted
    pub slot: u64,
    /// The slot at which the order was created
    pub creation_slot: u64,
    /// The slot at which the order expires
    pub expiration_slot: u64,
    /// The amount of input tokens to be exchanged
    pub amount: u64,
    /// The amount of input tokens that have been filled
    pub amount_filled: u64,
    /// The amount of output tokens that have been exchanged
    pub out_amount_filled: u64,
    /// The amount of fees paid in the smallest unit of from_token mint
    pub fees_paid: u64,
    /// Price base in the order, in the smallest unit of output token
    pub price_base: u64,
    /// Price exponent, price is calculated as price_base * 10^(-price_exponent)
    pub price_exponent: u8,
    /// Time in order, used to determine how long the order is valid
    pub time_in_force: u8,
    /// Fee rate in ticks, used to determine the fee charged for the order
    pub fee_ticks: u8,
}

---

Instruction discriminators

The discriminator field is always 0. The instruction field identifies which operation triggered the event:

• 1 — PlaceOrder — A new limit order was created.

• 2 — TakeOrder — A searcher filled (partially or fully) an order.

• 3 — CancelOrder — The maker cancelled the order.

• 4 — ModifyOrder — The maker modified the order parameters.

• 5 — WithdrawFilled — The maker withdrew filled output tokens from a partially filled order.

• 6 — CloseExpired — An expired order was closed and rent reclaimed.

The status field in the event reflects the order's state after the operation. Use OrderStatus values to interpret it.

---

Related pages

• Limit Orders Overview — Order structure, time-in-force, order status, fees

• Placing Taker Orders — TakeOrder instruction and execution code

• Error Codes — Program error codes