> For the complete documentation index, see [llms.txt](https://titan-exchange.gitbook.io/titan/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://titan-exchange.gitbook.io/titan/developer-doc/searchers-limit-orders/events.md).

# Limit Order Events

**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

```rust
#[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.

{% hint style="info" %}
The `status` field in the event reflects the order's state **after** the operation. Use [OrderStatus](/titan/developer-doc/searchers-limit-orders/overview.md#order-status) values to interpret it.
{% endhint %}

***

## Related pages

* [Limit Orders Overview](/titan/developer-doc/searchers-limit-orders/overview.md) — Order structure, time-in-force, order status, fees
* [Placing Taker Orders](/titan/developer-doc/searchers-limit-orders/take-order.md) — TakeOrder instruction and execution code
* [Error Codes](/titan/developer-doc/searchers-limit-orders/error-codes.md) — Program error codes