Costco Same-Day prices per store as JSON
This API reads sameday.costco.com, Costco Same-Day's online shop, live and returns it as JSON.
7 active endpoints, on 1 and 3 credit tiers.
- POST/costco-sameday/v1/search
- POST/costco-sameday/v1/category
- POST/costco-sameday/v1/product/detail
- POST/costco-sameday/v1/categories
- POST/costco-sameday/v1/stores
- POST/costco-sameday/v1/offers
- POST/costco-sameday/v1/promotions
What Costco Same-Day endpoints does ReefAPI ship?
7 live read endpoints. Read-only data API: no writes, no account actions, no dashboard access on the target site.
Costco Same-Day API
4 of 7 endpoints, ready to run
Milk at a Costco near 98027
// Press "Try it" and this pane shows exactly what the // live site returned this second — including an empty // result, if that is the truth. No key, no account.
How the Costco Same-Day API works
Costco Same-Day is a normal ReefAPI surface — the same four rules that hold for every other engine on the key.
No OAuth app, no request signing, no per-site account. One key covers all 585 engines.
Every route is a POST with a JSON body. Parameters are validated against the published schema before anything is charged.
Credits, not seats. Failed and blocked calls are never charged, and cache hits cost nothing.
One envelope everywhere. meta carries latency_ms, record_count and the endpoint that answered.
From a ZIP code to this week's Costco Same-Day deals at the nearest store
Pick a store, list the deals, then search its prices.
Costco stores nearest first, with store_id, distance and services.
The live deal lists with their product counts.
The deal products with price, regular price and promotions.
The same store's prices for any search.
One Costco store's current deals and prices, refreshable every day.
curl -X POST https://api.reefapi.com/costco-sameday/v1/search \
-H "x-api-key: $REEF_KEY" \
-H "content-type: application/json" \
-d '{"query":"milk","postal_code":"98027"}'{
"ok": true,
"data": { … },
"meta": {
"api": "costco-sameday",
"endpoint": "search",
"mode": "live",
"latency_ms": …,
"record_count": …
},
"error": null
}What a Costco Same-Day field actually contains
Fields that read differently from how they look, measured on live responses on 2026-10-18.
| Field | What it holds |
|---|---|
| price, price_display | The price at the chosen store as the sameday.costco.com product page prints it (matched on 8/8 products, e.g. Kirkland Signature Eggs, Large, 24-cou $3.96). |
| original_price, discount_percent | The struck-through regular price on sale items and the discount computed from the two prices; null when the item is not on sale. |
| promotions, buy_one_get_one | Deals shown on the item: BOGO, multi-buy ('Buy 2 for $9.16'), member offers. They are never folded into price. |
| loyalty_price | A separate card or member price when the site shows one next to the regular price; null otherwise. |
| store, store_defaulted | The Costco store that priced the response (id, name, street, city). store_defaulted is true when you gave neither postal_code nor store_id. |
| unit_price_text | The unit price as the site prints it ("$0.03/fl oz"). For items sold by weight, price is the estimated package price and price_is_estimate is true. |
| stock_level, likely_out_of_stock | many_in_stock, in_stock, likely_out_of_stock or out_of_stock for that store. |
| matches_query | Whether the row shares a word with your search. The site fills a search that matches nothing with unrelated products; such pages are dropped and counted in unmatched_dropped. |
Prices differ between stores: the same 14 products cost differently on 7 of them at a store near 90210 on the same day.
Costco Same-Day coverage, measured
Every number was read from live responses on 2026-10-18: 24 calls across all seven actions.
8 of 8 products: price matched the price printed on the sameday.costco.com product page.
A second store near 90210 priced 7 of 14 common products differently.
14 stores around 98027.
Weekly Savings 454 products at the default store.
The site re-ranked between calls (two products repeated across page 2 and 3 by page number). With next_cursor: 3 pages twice for 5 lists across 4 shops, no product repeated.
Across 133 rows: price, size, image and stock level on all; brand 129; unit price 79; regular price on sale items 24; promotions 24.
No sorting or filters beyond the store; no stock counts, only a stock level; product reviews are not returned.
What people build with Costco Same-Day
The jobs this data is most often used for.
endpoints
credits per call
Track Costco Same-Day prices per warehouse and ZIP code.
Compare Kirkland Signature prices between Costco warehouses.
Publish Costco Weekly Savings in a deals feed.
Build a Costco warehouse finder for same-day delivery coverage.
What Costco Same-Day data costs
The cheapest call here is 1 credit, so $15/mo (Pro) buys 10,000 of them — $1.50 per 1,000 credits. Credits roll over and never expire, and failed or blocked calls are not charged.
Full pricing →- 1,000 free credits on signup, no card
- One key, all 585 APIs, one credit pool
- Failed and blocked calls are never charged
- Credits roll over and never expire
Call it in two lines
Sign up, get 1,000 credits and one key that works on every engine. Then this is the whole protocol.
curl -X POST https://api.reefapi.com/costco-sameday/v1/search \
-H "x-api-key: $REEF_KEY" \
-H "content-type: application/json" \
-d '{"query":"milk","postal_code":"98027"}'import requests
r = requests.post(
"https://api.reefapi.com/costco-sameday/v1/search",
headers={"x-api-key": REEF_KEY},
json={
"query": "milk",
"postal_code": "98027"
},
)
print(r.json()["data"])Have a question? We got answers.
The questions people actually ask before wiring up Costco Same-Day.
Get a free key →Does Costco Same-Day have a public API?▾
No public product API. This API reads what sameday.costco.com shows a logged-out visitor and returns it as JSON. No account is needed.
Why do I need a ZIP code?▾
Costco prices are set per store. Pass postal_code or store_id; without them a fixed default store is used and store_defaulted is true.
Which price is returned?▾
The Costco Same-Day delivery price of the chosen warehouse, as sameday.costco.com prints it on its product page (8 of 8 products matched). In-warehouse shelf prices are not shown on the site and are not returned.
Can I get Costco's weekly savings?▾
Yes. offers with type weekly_savings returns the Weekly Savings list priced at one warehouse; promotions lists it with its product count.
Are these Costco warehouse prices?▾
These are the Costco Same-Day prices sameday.costco.com shows for a warehouse; they matched the price printed on the site's own product page for 8 of 8 products. No member-only price is shown to a visitor without a Costco login, so none is returned.
How do I find Costco stores near a ZIP code?▾
Call stores with postal_code. Around 98027 it returned 14 stores, nearest first, with address, coordinates, distance in miles and the services each offers. Use a store_id in any other call to price at that store.
Does search return everything the site finds?▾
Yes, in the site's own order, 20 per page by default (up to 40). cheese returned 139 products. The site can re-rank its list between two calls, so reading by page number can repeat or skip a product; follow next_cursor from each answer for a complete scan: it never returns a product twice and fills the page from the rest of the list.
How fresh is the data?▾
Every call reads sameday.costco.com live; nothing is cached on our side.
What is the Costco Same-Day API?▾
Costco Same-Day API is a ReefAPI endpoint group for sameday.costco.com prices as json per store: search, categories, weekly savings, product details and the store locator. It returns live JSON through POST requests under /costco-sameday/v1.
Is the Costco Same-Day API free to try?▾
Yes. ReefAPI starts with 1,000 free credits, no card required. Costco Same-Day calls use the same shared credit balance as every other ReefAPI engine.
Do I need a Costco Same-Day login or account?▾
No login to Costco Same-Day is needed for the API response. You call ReefAPI with your x-api-key header, and the playground can run live examples before you create a production key.
How fresh is the Costco Same-Day data?▾
The page example is captured from a live search call, and production requests fetch live data through ReefAPI rather than a static sample.
How many credits does the Costco Same-Day API use?▾
Costco Same-Day actions currently cost 1-3 credits per successful call. Failed or blocked calls are free. All APIs draw from one credit pool.
Can I call Costco Same-Day from an AI assistant or MCP client?▾
Yes. Connect ReefAPI once through MCP and your assistant can call costco-sameday actions with the same key, credit pool and JSON envelope used by normal REST requests.
320 E-commerce & Marketplaces APIs on the same key
One key, one credit pool, one response envelope. If you are pulling Costco Same-Day, you are one call away from the rest of the category — no second contract, no second integration.
Need something this API does not do?
Name the endpoint, the field, or a source we do not carry yet. We ship new APIs every week and you would be first to get the key. Real people read every message and reply the same day.
Try it on your own data before you pay anything
The call above is the real endpoint, not a recording. A free key gives you 1,000 credits, the other 584 APIs, and the same envelope everywhere.
Endpoints, parameters and credit costs on this page are read from the live catalog and cannot drift from what the API accepts. Field notes were captured on 2026-10-18.