GET /v1/weights

Weights of formats, hooks and targets

Weights of formats, hook types and targets from measured signals only (days live, EU reach, reach growth, versions), each with its sample size, median and top 10%. Weights under the minimum sample are never shown. Until the weighting engine runs this returns nothing. 10 credits per query (0 if nothing is returned).

Cost: 10 credits per call. A call that returns nothing costs 0.

Parameters

Parameter	Type	What it does
`dimension`	string	format, hook_type, target_country, target_age_gender…
`value`	string
`signal`	string
`niche`	string
`country`	string
`limit`	integer	Min 1. Max 50.

Errors

`400`	A parameter is refused (the answer lists the accepted values). Not billed.
`401`	Missing, unknown or revoked API key.
`402`	Not enough credits for this call. Credits never expire; top up with a pack.
`429`	Too many requests for this key. Wait Retry-After seconds. Not billed.
`503`	Server busy or a query took too long. Retry. Not billed.

Request

curl -s "https://api.askposeidon.app/v1/weights?dimension=format&niche=weight%20loss" \
  -H "Authorization: Bearer $POSEIDON_API_KEY"

Response

{
  "data": {
    "rows": [
      {
        "dimension": "format",
        "value": "VIDEO",
        "cohort": {
          "niche": "weight loss"
        },
        "signal": "days_live",
        "sample_size": 5750,
        "median": 48.0,
        "p90": 212.0,
        "computed_at": "2026-11-12T22:08:10.629853+00:00",
        "formula_version": "weight-v2"
      },
      {
        "dimension": "format",
        "value": "VIDEO",
        "cohort": {
          "niche": "weight loss"
        },
        "signal": "active",
        "sample_size": 5750,
        "median": 1.0,
        "p90": 1.0,
        "computed_at": "2026-11-12T22:08:10.629853+00:00",
        "formula_version": "weight-v2"
      }
    ],
    "minimum_sample": 30
  },
  "meta": {
    "endpoint": "get_weights",
    "api_version": "1.1.0",
    "credits_charged": 10,
    "credits_left": 500,
    "answered_at": "2026-11-12T22:11:37+00:00",
    "coverage": "Ads delivered in the EU or UK only. The only number of people shown is Meta's EU total reach (eu_reach, \"EU reach (Meta's total)\"), as read on the date shown. Meta publishes no spend or impressions for commercial ads. Countries, ages and genders are shown only as shares of Meta's age x gender breakdown of the same read, never as numbers of people: Meta's breakdown rows do not add up to its EU total (measured 0.93x to 1.10x on 3,820 reads), so a country figure in people would not be a fact."
  }
}