Bond-zone alerts

A “bond zone” is the near-certain end of a market: an outcome trading at, say, ≥ 95¢ (almost certain to win) or ≤ 5¢ (almost certain to lose). The close_to_bond event fires when a trade prints inside a zone you define, so you can react to outcomes that are effectively resolved before the oracle settles them. The same event and filters are available two ways:

Transport	How it arrives	Reference
Webhook	HTTP `POST` to your endpoint	`close-to-bond` callback
Websocket	Pushed over a live connection	`close_to_bond` alert

When to use this

Resolution front-running: surface markets the crowd already treats as decided, ahead of on-chain settlement.
Risk / exit signals: alert when a position you hold flips to near-certain-loss so you can exit the remaining size.
Mispricing scans: watch one side of a market for prints at the opposite extreme of where you think it should trade.

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.

Examples

A near-certain-win alert for one specific market, Yes side only:

{
  "condition_ids": ["0x19b3cbe24efa387cac21271dd869cb1121432cd212308f3a6e3ec2f7a8614b9d"],
  "min_price": 0.95,
  "position_outcome_indices": [0]
}

Near-certain wins across whole categories, scoped by tags:

{
  "min_price": 0.95,
  "tags": ["Sports", "Crypto Prices"],
  "position_outcome_indices": [0]
}

tags matches a market’s tags or its category by display label (for example "Sports", "Crypto Prices"), case-insensitive. Both extremes, scoped to the Yes/Up token so each event alerts once:

{
  "min_price": 0.90,
  "max_price": 0.10,
  "position_outcome_indices": [0],
  "exclude_shortterm_markets": true
}

Two-edge mode (min_price > max_price) fires from both tokens. On a near-certain market the Yes token near 90¢ triggers bond_side: "high" and the No token near 10¢ triggers bond_side: "low", so each event arrives as two separate deliveries. Add position_outcome_indices: [0] (Yes/Up only) to watch one side and get one delivery per extreme.

Reading the payload

Every delivery tells you which zone was hit and the threshold it breached:

bond_side: "high" (near-certain) or "low" (near-zero).
threshold: the filter value that was breached. In bounded-range mode this is min_price.
price: the value that triggered the alert, on a 0.0–1.0 scale.

See the full field list on the websocket alert page.

Available filters

Filter	Type	Description
`min_price`	number	High-edge / lower bound of the zone, `0.0`–`1.0`.
`max_price`	number	Low-edge / upper bound of the zone, `0.0`–`1.0`.
`condition_ids`	string[]	Restrict to specific markets (max 500).
`position_ids`	string[]	Restrict to specific outcome tokens (max 500).
`outcomes`	string[]	Restrict by outcome name, e.g. `["Yes", "No"]` (max 500).
`position_outcome_indices`	number[]	Restrict by outcome index: `0` (Yes/Up) or `1` (No).
`event_slugs`	string[]	Restrict to specific events (max 500).
`tags`	string[]	Restrict to markets carrying any of these tags or category names, case-insensitive (max 500).
`series_slugs`	string[]	Restrict to markets in any of these series by slug, case-insensitive (max 500).
`exclude_shortterm_markets`	boolean	Exclude short-term Up/Down markets.

At least one of min_price or max_price is required. Without either, every trade in every market would fire.

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.

Essentials

Data access

Markets

Traders & positions

PnL

Charts & feeds

Builders

Holders

Alerts

When to use this

Defining the bond zone

Alerting on near-certain outcomes

How price is read

Picking the right side

Examples

Reading the payload

Available filters

​When to use this

​Defining the bond zone

​Alerting on near-certain outcomes

​How price is read

​Picking the right side

​Examples

​Reading the payload

​Available filters

When to use this

Defining the bond zone

Alerting on near-certain outcomes

How price is read

Picking the right side

Examples

Reading the payload

Available filters