Close to Bond

Event: close_to_bond
Endpoint: wss://api.struct.to/ws/alerts
Cost: 0.2 credits per event

Get notified when a trade occurs at a near-certain-outcome price. At least one of min_price or max_price is required to define the bond zone.

Related guide: Bond-zone alerts is a worked walkthrough of this event across both websockets and webhooks.

Defining the bond zone

The bond zone is defined entirely by how you combine min_price and max_price. The relationship between the two values selects one of four modes:

You set	Mode	Fires when	`bond_side`
`min_price` only	Single high edge	`price ≥ min_price`	`"high"`
`max_price` only	Single low edge	`price ≤ max_price`	`"low"`
Both, with `min < max`	Bounded range	`min_price ≤ price ≤ max_price`	`"high"`
Both, with `min > max`	Two edges	`price ≥ min_price` or `price ≤ max_price`	`"high"` or `"low"`

min < max is a band, not a bond. If you set min_price: 0.75 and max_price: 0.90, you do not get “fires above 90% or below 75%”. Because min < max, it switches to bounded-range mode and fires only when the price lands inside the 75–90% band. To alert on the two near-certain extremes, you must set min > max (see below).

Alerting on near-certain outcomes

To get notified when an outcome becomes near-certain in either direction (at or above 90% or at or below 10%), set min_price higher than max_price:

{
  "min_price": 0.90,
  "max_price": 0.10
}

Because 0.90 > 0.10, this is read as two separate edges. A trade at 96¢ fires with bond_side: "high"; a trade at 4¢ fires with bond_side: "low". For a single edge, set just one of the two.

How price is read

The traded position’s own price is used: the price of the exact outcome token (position_id) that printed.
Trades at a price of exactly 0 or 1 are skipped, since there is no remaining risk to alert on.
price is on a 0.0–1.0 scale (so 95¢ = 0.95).

Picking the right side

On a binary market, “YES at ≤10%” and “NO at ≥90%” are the same event priced from opposite tokens. If you add position_outcome_indices: [0] you will only ever see trades that print on the Yes/Up token (index 0); trades on the No token (index 1) won’t fire even when they hit the same bond zone. Omit position_outcome_indices to catch the zone regardless of which side the trade prints on.

Filters

Filter	Type	Required	Description
`min_price`	number	Yes*	High zone threshold, 0.0-1.0 (e.g. 0.95). *At least one of `min_price` or `max_price` is required.
`max_price`	number	Yes*	Low zone threshold, 0.0-1.0 (e.g. 0.05). *At least one of `min_price` or `max_price` is required.
`condition_ids`	string[]	No	Restrict to specific conditions (max 500)
`position_ids`	string[]	No	Restrict to specific positions (max 500)
`outcomes`	string[]	No	Filter by outcome name, e.g. `["Yes", "No"]` (max 500)
`position_outcome_indices`	number[]	No	Filter by outcome index: 0 or 1 (max 500)
`event_slugs`	string[]	No	Restrict to specific events (max 500)
`tags`	string[]	No	Restrict to markets carrying any of these tags or category names, case-insensitive (max 500)
`series_slugs`	string[]	No	Restrict to markets in any of these series by slug, case-insensitive (max 500)
`exclude_shortterm_markets`	boolean	No	Exclude short-term markets from results

Scope by market taxonomy. tags matches a market’s own tags or its category, given as the display label shown on Polymarket (for example "Sports", "Politics", or "FIFA World Cup"), not a slug. series_slugs matches the market’s parent series by slug (for example "nba-finals"). Both are case-insensitive, accept up to 500 values each, and an empty or omitted list applies no taxonomy restriction.

Single high edge: fire when an outcome is near-certain (≥ 95%):

{
  "op": "subscribe",
  "event": "close_to_bond",
  "min_price": 0.95
}

Both edges: fire when an outcome is near-certain in either direction (≥ 90% or ≤ 10%). Note min_price is set higher than max_price:

{
  "op": "subscribe",
  "event": "close_to_bond",
  "min_price": 0.90,
  "max_price": 0.10
}

Response

{
  "event": "close_to_bond",
  "timestamp": 1775913505260,
  "data": {
    "trader": "0x9d84cef98b41a5b88dafb55c05e9a7e0f1a4f4d6",
    "taker": "0x4bfb41d5b3570defd03c39a9a4d8de6bd8b8982e",
    "position_id": "452312848583266388373324160190187140051835877600158453279131187530910662656",
    "condition_id": "0x4fec624c0ff2bfae89956cebd6fbc9c58f995f824382dc587dc5a32a4b15940b",
    "outcome": "Yes",
    "outcome_index": 0,
    "question": "Will candidate X win the 2028 election?",
    "market_slug": "will-candidate-x-win",
    "event_slug": "us-presidential-election-2028",
    "trade_id": "0x9a8b7c6d5e4f3a2b1c0d9e8f7a6b5c4d3e2f1a0b",
    "hash": "0x1f2e3d4c5b6a7988deadbeefcafebabe0011223344556677889900aabbccddee",
    "block": 19456789,
    "confirmed_at": 1713012000,
    "amount_usd": 5000.00,
    "shares_amount": 5263.16,
    "fee": 50.00,
    "side": "Buy",
    "price": 0.96,
    "bond_side": "high",
    "threshold": 0.95
  }
}

Introduction

Rooms

Alerts

Defining the bond zone

Alerting on near-certain outcomes

How price is read

Picking the right side

Filters

Response

​Defining the bond zone

​Alerting on near-certain outcomes

​How price is read

​Picking the right side

​Filters

​Subscribe

​Response

Defining the bond zone

Alerting on near-certain outcomes

How price is read

Picking the right side

Filters

Subscribe

Response