Mercadona Product and Price Tracker (Spain)

Read the online catalogue of Mercadona, Spain's largest supermarket, as flat rows: name, price, previous price and a price-drop flag, price per kg or litre, VAT rate, category path, pack size, photo and product URL. Pick a region (six Mercadona warehouses), one category or the whole range (about 4,300 products), and tell it to return only what is new or re-priced since your last run. Schedule it daily to get a price-watch feed that costs nothing for products that did not move.

Input

Field	Notes
categoryIds	Mercadona category ids. A top-level id (1 Fruta y verdura, 3 Carne, 12 Aceite, especias y salsas) reads all of its sub-categories; a sub-category id (27 Fruta, 43 Embutido) reads just that one. Empty = the whole catalogue. Every row carries top_category_id and category_id.
warehouse	vlc1 Valencia (default), bcn1 Barcelona, mad1 / mad2 Madrid, alc1 Alicante, svq1 Sevilla. See Regions below.
language	es (default), en or ca: language of product and category names. Prices do not change.
maxItems	Stop after this many products (default 100, so a default run reads only the first few categories). Raise it to 5000 for the whole catalogue.
changesOnly	Return and charge only products that are new to this watch or re-priced since the last run of the same warehouse and category ids.

Output

Field	Notes
change	new, price_drop, price_rise or unchanged, compared with the previous run of the same warehouse and category ids.
product_id, slug, name, url, thumbnail_url	url is Mercadona's own share link.
packaging, main_feature	How it is sold ("Bandeja", "Pack-10") and Mercadona's qualifier ("ultracongelado"). Null when Mercadona sends none or an empty string.
top_category_id, top_category, category_id, category, group_id, group, category_path	The three levels Mercadona files a product under, and the whole path joined with " > ".
unit_price	EUR, VAT included, for one sales unit as on the shelf label.
previous_price, is_price_drop	Mercadona's "was" price when it shows one, and whether it is above unit_price.
bulk_price, reference_price, reference_format	The price per kg, litre or piece, and the shelf-label figure with its unit ("kg", "L", "100 ml").
unit_size, size_format, approx_size, drained_weight	Content of one unit (0.17 kg for a banana), its unit, whether the weight is an average, and the drained weight for tinned and frozen goods.
unit_name, total_units, is_pack, pack_size	Multi-pack detail: bolsitas, 4.
iva_percent	VAT rate: 4, 10 or 21.
is_new	Mercadona's new-arrival flag.
requires_age_check, is_water	Mercadona's own badges (alcohol needs an age check at delivery).
max_quantity	Most units per order. Mercadona sends 999 almost everywhere, which means no practical cap; 10 and 20 are real limits.
unavailable_from, unavailable_weekdays	When a product stops being deliverable, and the weekdays it cannot be delivered on (Mercadona's numbering).
warehouse, language	Which warehouse's prices these are.

Prices are in EUR. There is no currency column because Mercadona sends none.

Honest nulls, and three Mercadona flags that do not work

A field Mercadona did not send is null, never 0 or "". previous_price is null for the 96 % of products with no reduction - a 0 would read as a price cut to nothing.

Mercadona's own JSON sends every price as a string, and pads the previous price with spaces (" 3.15"); they are stripped and turned into numbers here. Three of its flags were measured to be useless on 2026-10-07, over all 4,320 products, so they are not passed through:

• price_decreased is false on all 161 products that have a previous price. is_price_drop is computed from the two prices instead.
• price_instructions.is_new is false on all 4,320 products while 85 are flagged new at product level. is_new reads the product-level flag.
• iva is null on 73 % of products; tax_percentage is always there and equals it when both are set. iva_percent reads tax_percentage.

A product Mercadona lists under several sub-categories (271 repeats across the 152 sub-categories) is emitted and charged once, under the first one reached.

Regions

Mercadona prices and stocks per warehouse. Against Valencia's catalogue, Barcelona (bcn1) repriced 22 of the 43 products in category 27 and changed which are stocked (two added, one gone); Madrid (mad1) repriced 24 and added two (2026-10-07). Valencia is also what the API serves when you send no warehouse at all.

Only six codes answered with a real catalogue. Any other code is not refused by Mercadona - it silently returns Valencia's catalogue (43 of the 50 other codes tried did exactly that), so a typo would give you Valencia prices labelled as another region. This actor therefore accepts only the six measured codes and refuses the rest. Two further codes, pmi1 and vlc2, are recognised but answer an empty category tree, so they are not offered. The city names are read off the code prefix; Mercadona does not say, and which warehouse a given postal code is served from was not measured.

Change tracking

Each watch (warehouse plus category ids) has its own memory, kept in a named key-value store on your Apify account (mercadona-products-watch), so it is never visible to anyone else. The first run of a watch has nothing to compare against: it labels every product new. From the second run on, a product is new if the last run did not see it, price_drop / price_rise if its unit_price moved, and unchanged otherwise. The memory is kept on every run, so the change column is always filled; changesOnly just stops the unchanged rows from being returned and charged.

Changes are detected on the products a run actually reads: a run capped by maxItems compares only those, and the rest keep their last known price.

Pricing

Pay per event:

• $0.002 per run (actor-start), charged only after your input is validated - a run that fails on bad input costs nothing.
• $0.00021 per product row written (product-scraped), i.e. $0.21 per 1,000 products - about $0.90 for the whole catalogue. With changesOnly, unchanged products are not charged.

How it fetches

It calls the same JSON API Mercadona's website uses (tienda.mercadona.es/api/categories/): one request for the category tree, then one per sub-category (up to 291 products each). No account, no login and no postal code. Apify datacenter proxy is the default; the API answered an Apify datacenter exit with the full JSON on 2026-10-06, and a plain home connection on 2026-10-07.