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Event: price_threshold
Cost: 0.2 credits per delivery
The price_threshold event fires when an outcome’s price (implied probability) crosses a target level you set. It is edge-triggered: it fires once on the crossing, not on every trade that stays past the level. The full payload schema is in the auto-generated Price Threshold callback reference; this page documents the filters and matching behavior.

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When to use this

  • Alert the moment an outcome crosses up through a level (e.g. YES reaches 75%) or down through one (e.g. YES falls to 25%).
  • Build one-time triggers that delete themselves after firing, with one_shot.
  • Catch positions that are already past your target when you subscribe, with fire_if_already_past.

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Defining the threshold

Set min_probability for an upward target (fire when the price crosses up to ≥ that value) and max_probability for a downward target (fire when the price crosses down to ≤ that value). At least one is required; set both to watch a position from either side. By default the event waits for a real crossing: it needs a prior observation on the other side of the target before it fires. Set fire_if_already_past to fire immediately when the first observed price is already past the target.

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Subscription filters

Add these to the filters object when you create the subscription. At least one of min_probability or max_probability is required.
FilterTypeDescription
min_probabilitynumberUpward target, 0.0–1.0. Fire when the price crosses up to ≥ this value (e.g. 0.75).
max_probabilitynumberDownward target, 0.0–1.0. Fire when the price crosses down to ≤ this value (e.g. 0.25).
one_shotbooleanDelete the subscription after its first delivery (fire-and-delete). Requires position_ids or condition_ids. Defaults to false.
fire_if_already_pastbooleanFire immediately if the first observed price is already past the target, with no prior baseline. Defaults to false.
condition_idsstring[]Restrict to specific markets by condition ID (max 500).
position_idsstring[]Restrict to specific outcome tokens by position ID (max 500).
outcomesstring[]Restrict by outcome name, e.g. ["Yes", "No"] (max 500).
position_outcome_indicesnumber[]Restrict by outcome index: 0 (Yes/Up) or 1 (No).
event_slugsstring[]Restrict to specific events by slug (max 500).
tagsstring[]Restrict to markets carrying any of these tags or category names, case-insensitive (max 500).
series_slugsstring[]Restrict to markets in any of these series by slug, case-insensitive (max 500).
exclude_shortterm_marketsbooleanExclude short-term Up/Down markets.
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.

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Example

Fire once when a specific market’s YES outcome crosses up through 75%, then delete the subscription: 
{
  "url": "https://your-server.com/webhooks",
  "event": "price_threshold",
  "filters": {
    "condition_ids": ["0x4fec624c0ff2bfae89956cebd6fbc9c58f995f824382dc587dc5a32a4b15940b"],
    "min_probability": 0.75,
    "one_shot": true
  }
}

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Notes

  • The event is edge-triggered: it fires on the transition past the target, then re-arms once the price moves back to the other side (unless one_shot deleted the subscription).
  • The payload reports the crossing direction ("up" or "down"), the threshold that was crossed, and previous_price (the baseline the crossing was measured from).
  • one_shot requires position_ids or condition_ids so the subscription targets a bounded set of markets.
Last modified on June 15, 2026