GET /v1/brands/{page_id}/changes

What changed for a brand since a date

Watch a competitor: what changed for one brand since a date. Use it for 'what's new from <brand>', 'did they launch or stop ads', 'what is scaling for them this week'. Returns, each with its date and source: ads started (Meta's start date), ads stopped (Meta's stop date), ads whose version count rose, new ads relaunching a media the brand already used, and the ads whose EU reach grew most between two readings. Get the page_id with find_brand. Costs 5 credits (0 if nothing changed).

Cost: 5 credits per call. A call that returns nothing costs 0.

Parameters

Parameter	Type	What it does
`page_id` required	string
`since`	string

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.
`404`	Not in Poseidon.
`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/brands/2218331548432159/changes?since=2026-11-01" \
  -H "Authorization: Bearer $POSEIDON_API_KEY"

Response

{
  "data": {
    "brand": {
      "page_id": "2218331548432159",
      "name": "Epycure",
      "shop_domain": "epycure.com"
    },
    "since": "2026-11-01",
    "started": [],
    "stopped": [
      {
        "ad_id": "1846559006694732",
        "library_url": "https://www.facebook.com/ads/library/?id=1846559006694732",
        "stopped": "2026-11-13",
        "started": "2026-10-31",
        "days_live": 13,
        "source": "Meta's stop date"
      },
      {
        "ad_id": "1019162297879814",
        "library_url": "https://www.facebook.com/ads/library/?id=1019162297879814",
        "stopped": "2026-11-13",
        "started": "2026-10-31",
        "days_live": 13,
        "source": "Meta's stop date"
      }
    ],
    "more_versions": [],
    "relaunched_media": [],
    "reach_movers": [],
    "reach_movers_coverage": {
      "ads": 30,
      "ads_with_2_reach_readings_since": 0,
      "note": "reach growth can only be shown for ads read at least twice after 'since'"
    },
    "coverage": "Started and stopped come from Meta's own dates. Version changes come from Poseidon's readings since 2026-11-12. Reach growth needs two readings of the same ad after 'since'. New products appear once shop catalogs are read (not yet)."
  },
  "meta": {
    "endpoint": "brand_changes",
    "api_version": "1.22.2",
    "credits_charged": 5,
    "credits_left": 1115,
    "answered_at": "2026-11-13T14:59:52+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."
  }
}