> ## Documentation Index
> Fetch the complete documentation index at: https://docs.bayse.markets/llms.txt
> Use this file to discover all available pages before exploring further.

# v0.1.13 — May 18, 2026

> Batch amend orders endpoint, batch place / amend cap reduced to 20

## New endpoint

### Batch amend orders — `POST /v1/pm/orders/batch/amend`

Modify the price and/or size of up to 20 open CLOB orders in a single round-trip. The natural complement to batch place and batch cancel — designed for market makers running cancel-and-replace ladders who want to keep time priority where possible instead of always going to the tail of the queue.

```json theme={null}
{
  "items": [
    {
      "orderId": "f6a7b8c9-d0e1-2345-fabc-678901234567",
      "newPrice": 0.50,
      "newSize": 15
    },
    {
      "orderId": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
      "newPrice": 0.40,
      "newSize": 8
    }
  ]
}
```

Key behavior:

* **`newPrice` and `newSize` are independently optional** — supply one or both. The omitted field keeps its current value. Items with neither field are rejected per-item with `BAD_REQUEST`.
* **Total size, not delta** — `newSize` is the new TOTAL size in the order's original currency. For partial-filled orders the new remaining becomes `newSize − filledSize`.
* **Per-item failure isolation** — bad items return their own error without aborting siblings. Failures use the same per-item shape as the place/cancel batches.
* **Funding rejection codes** — `INSUFFICIENT_BALANCE` (BID amend exceeds wallet) and `INSUFFICIENT_SHARES` (ASK amend exceeds free shares) surface per-item rather than failing the whole call.
* **Cross-market** — items may target orders in different markets and events.
* **Time priority** — preserved when the new `(price, size)` is unchanged or shrunk at the same price level. Price moves go to the new tail.
* **Self-trade prevention** — fixed server policy: amend always uses `CANCEL_OLDEST` to resolve same-user crossers at the new price. The order's resting `stpMode` (set at placement) governs matching, not amend. Crossers being amended in the same batch are excluded from the cancel set.
* **Idempotency** — supports the standard `Idempotency-Key` header with the same 24-hour replay semantics as the other batch endpoints.

Requires [write authentication](/authentication). Charged one rate-limit token per item against the write bucket.

See [Batch amend orders](/api-reference/pm/batch-amend-orders) for the full schema and [Order lifecycle](/concepts/order-lifecycle#amending-an-open-order) for the funding and time-priority semantics.

***

## Breaking changes

### Batch place + amend max items: **50 → 20**

Both `POST /v1/pm/orders/batch` and `POST /v1/pm/orders/batch/amend` now accept at most **20 items per call** (was 50 for batch place). Larger payloads are rejected with `400 BAD_REQUEST` before any items reach the matching engine. The cap on `DELETE /v1/pm/orders/batch` (batch cancel) is unchanged at **100**.

Rationale: bound wallet round-trips and DB statement sizes under high-frequency cancel-and-replace ladders. Existing integrations sending up to 20 items per batch are unaffected.

***

## Enhancements

### Cancel-and-replace cycle guidance

The [Batch orders](/concepts/batch-orders) concept page documents the canonical three-step cycle for re-quoting: `cancel → amend → place`. Each step's wallet/balance state is visible to the next, so size-up amends in step 2 can use capacity freed by step 1.

### Amend section in order lifecycle

[Order lifecycle](/concepts/order-lifecycle) now describes amend semantics, time-priority preservation, and per-side funding checks.