Steam Price & Market Monitor

Tracks Steam game prices and discounts — including exactly when each sale ends — and Community Market item prices with listing counts and 24-hour volume. In monitor mode it tells you what moved since the last run.

Uses Steam's own public APIs. No key, no login, no browser, no CAPTCHA solving.

Two modes

Store — games

Price, original price, discount % and discountEndsAt: the exact moment the sale expires. That last one turns a price list into a deadline — «$17.99 instead of $59.99, until 10 August».

Optional extras, each one request per game:

• fullDetails — developers, publishers, genres, platforms, release date, Metacritic, plus Steam's own review verdict (reviewScoreDesc, e.g. "Overwhelmingly Positive", with the total review count).
• withPlayerCount — playersOnline, how many people are in the game right now. Counter-Strike 2 reads 672,128 as this is written. It is the demand signal a price-only scraper cannot give you.

Games come from any mix of: search by name, exact app IDs, or Steam's own collections (specials, top_sellers, new_releases, coming_soon).

Market — Community Market items

CS2 skins, TF2 hats, Dota sets, trading cards. Per item: cheapest listing price, how many are listed, median price, 24-hour sales volume, item type, rarity colour, tradability and icon. Price plus liquidity is what a trader actually reads.

Pick the game with marketAppId: 730 = CS2 (~34,700 items), 440 = Team Fortress 2 (~41,600), 570 = Dota 2 (~33,700), 252490 = Rust.

Monitor mode

Compares against the previous run for the same search and country:

changeType	Means
new	First time seen in this scope
discount_start	A sale just began
discount_end	The sale is over
price_down / price_up	The price moved with no change in sale status
unchanged	Nothing moved

Sale start and end are checked before the plain price comparison, because a drop caused by a sale is a different event from a permanent price change — only the former reverts. Rows also carry previousPrice, priceLow30 and priceHigh30.

Turn on Output only changed items so each run returns just what moved.

Input

Field	What it does
What to track	store (games) or market (Community Market items). Everything below is tagged with the mode it applies to.
Search	Game names in store mode, item keywords in market mode.
App IDs (store)	Exact games, e.g. 730. Skips search entirely.
Collections (store)	Steam's own lists: specials, top_sellers, new_releases, coming_soon. Default specials — this is also the only source of discountEndsAt.
Full game details (store)	Developers, publishers, genres, platforms, release date, Metacritic, review verdict. One request per game.
Add live player count (store)	playersOnline — how many people are in the game right now. One request per game.
Market app (market)	Which game's items: 730 CS2, 440 TF2, 570 Dota 2, 252490 Rust.
Add median price & 24h volume (market)	Liquidity data per item. On by default.
Country / currency	Pricing region, e.g. us, de, ru. Some titles have no price in some regions.
Max pages (market)	The Market returns 10 items per page whatever you ask for, so pagination moves in tens.
Max results / Max concurrency	Overall row cap (0 = no cap) and parallel requests (default 4).
Monitor mode / Output only changed items	The alert behaviour above.

Notes & limits

Properties of Steam's API, measured rather than assumed:

• Prices come 50 games per request, full details one at a time. appdetails accepts a batch of app IDs only with filters=price_overview; asking for full data on two IDs returns nothing. That is why fullDetails is opt-in and flagged as costing one request per game.
• The Market returns 10 items per request whatever count says (verified up to 200), so market pagination moves in tens and a whole-game dump is expensive — narrow it with a keyword.
• No rate limiting at a sane pace — twelve rapid price lookups in a row all returned 200 — but the Actor still backs off and retries on HTTP 429.
• Some titles have no price in some regions. cc=ru in particular returns no price for many games; those rows come back with price: null rather than a guess.
• Sale end times come from Steam's featured collections, which is the only place discount_expiration is published — a game found purely by search may therefore have a discount but no discountEndsAt.
• Cost measured at $0.06 per 1,000 rows.