Amazon Date First Available API: When Was This ASIN Created?

listedSinceDate on /amazon-product-lookup is Amazon's own "Date First Available" label, parsed to YYYY-MM-DD - the date the ASIN was created, not necessarily when the product first shipped or went on sale. It is null when the page has no such label, or when the label is in a language the extraction does not match yet; on amazon.co.jp an ambiguous date (day and month both 12 or lower) can come back with day and month swapped.

How do I read the creation date for an ASIN?

Call /amazon-product-lookup and read productInfo.listedSinceDate. No extra parameter is needed; the field is simply present (a string) or null in the same response you would read for title and price.

A raw call for comparison (uses .get so a non-200 body never raises)

curl -s "https://sellermagnet-api.com/api/amazon-product-lookup?asin=B0CL61F39H&marketplaceId=ATVPDKIKX0DER" \
  -H "X-Api-Key: $SELLERMAGNET_API_KEY" | python3 -c "import json,sys; d=json.load(sys.stdin); print(d.get('data',{}).get('productInfo',{}).get('listedSinceDate'))"

listing_age.py - read Date First Available and handle the null/caveat cases

"""Read Date First Available and flag the two known caveats (null label, JP day/month ambiguity)."""
import datetime as dt

import requests

from retry import get_with_retry
from sellermagnet import ApiError, new_session

JAPAN_MARKETPLACE = "A1VC38T7YXB528"

session = new_session()


def listing_age(asin: str, marketplace_id: str = "ATVPDKIKX0DER") -> dict:
    try:
        data = get_with_retry(session, "amazon-product-lookup", asin=asin, marketplaceId=marketplace_id)
    except ApiError as err:
        return {"error": f"lookup failed ({err.status}): {err}"}
    except (requests.ConnectionError, requests.Timeout) as err:
        return {"error": f"network error: {err}"}
    raw = data["productInfo"].get("listedSinceDate")
    if raw is None:
        return {"listedSinceDate": None, "note": "no label matched on this marketplace, or none on the page"}
    try:
        created = dt.date.fromisoformat(raw)
    except ValueError:
        return {"listedSinceDate": raw, "note": "unparsable date string, show raw value"}
    note = ""
    if marketplace_id == JAPAN_MARKETPLACE and created.day <= 12 and created.month <= 12:
        # day-first parsing cannot tell "2024/3/5" (5 March) from "2024/5/3" (3 May): both parse the same way
        note = "amazon.co.jp: day and month are both 12 or lower, so they may be swapped - verify before date math"
    weeks_old = (dt.date.today() - created).days // 7
    return {"listedSinceDate": raw, "weeks_old": weeks_old, "note": note}


if __name__ == "__main__":
    print(listing_age("B0CL61F39H"))
    print(listing_age("B0CL61F39H", marketplace_id="A2NODRKZP88ZB9"))
    print(listing_age("B07ZZK3VPB", marketplace_id=JAPAN_MARKETPLACE))

Example output across three calls, from python listing_age.py (illustrative data)

{'listedSinceDate': '2021-03-15', 'weeks_old': 292, 'note': ''}
{'listedSinceDate': None, 'note': 'no label matched on this marketplace, or none on the page'}
{'listedSinceDate': '2024-05-03', 'weeks_old': 129, 'note': 'amazon.co.jp: day and month are both 12 or lower, so they may be swapped - verify before date math'}

Is this the same as listedSince on the statistics endpoint?

No. /amazon-product-statistics has its own listedSince (and trackingSince) fields, and they mark where THAT endpoint's own price/rank history starts, not when the product itself was created - a product first tracked in 2024 can have a 2019 listedSinceDate on the lookup endpoint. Use listedSinceDate from the lookup for the product's real age, and the statistics fields only to know how far back a price or rank chart goes; the price history guide and the sales rank history guide both rely on that history-start distinction.

What can I use the listing age for?

Listing age is a cheap signal for sourcing and research: a very young ASIN on an established niche can mean a new entrant worth watching, and a very old one that still sells well can mean a durable product worth sourcing. It is one input among several, not a verdict by itself - pair it with current rank and review count from the same lookup call before drawing a conclusion.

Bottom line: listedSinceDate on the product lookup is the closest thing to a listing's real birthday, matched across most but not all marketplace languages, with one open caveat on Japan. Every field is on the product lookup page.