Pricing algorithms

Every price the bot uses comes from one analysis run over Steam's public price history for that item. The run produces a buy price, a sell price, and a verdict on whether the item may be bought.

Two sides of every price

Steam charges the buyer; the seller receives less. XBOT tracks both:

The conversion uses a fixed multiplier of 1.15:

steam price = sell price × 1.15
sell price  = steam price ÷ 1.15

The analysis window

1. Steam's price history is read in the market timezone (America/Phoenix).
2. Points are bucketed: period = the last Analysis period days ending yesterday, plus week (7 days), month (30 days) and today. Today's trades never enter the pricing window — only the trend filters read them.
3. The Corridor filter drops points further than corridor % from the bucket average. With 0 nothing is dropped.
4. If the period bucket is empty after filtering — or Steam returned fewer than four history points — the analysis is skipped: the item keeps its current prices and no error is raised.

Algorithms

All five run on the same window; the group picks one for the buy side and one for the sell side independently. "Daily high/low" means the highest or lowest price a calendar day traded at.

Sell-anchored algorithms take their base price as the Steam price, strip the fee to get the sell price, then subtract the markup to get the buy price:

steam price = base
sell price  = base ÷ 1.15
buy price   = sell price − markup % of sell price

Buy goes the other way — the base price is the buy price, and the sell price is the price that yields the configured margin:

buy price   = base
sell price  = buy price ÷ (1 − markup / 100)
steam price = sell price × 1.15

Scaling

The chosen prices are then scaled by their own shares:

buy price  = buy algorithm price  × (Buy algorithm, %  ÷ 100)
sell price = sell algorithm price × (Sell algorithm, % ÷ 100)

The Steam price is re-derived from the scaled sell price. A share of 0 is treated as 100.

Outbidding

With Outbid the highest buy order enabled, a calculated buy price above the highest existing buy order is pulled down to that order plus one cent — enough to lead the queue, and no more. The option also forces an order-book request on every analysis.

Filters

Filters decide whether the item may be bought. They never change a price, and they never stop selling.

A filter set to 0 is disabled. One failing filter is enough to block the purchase; the item is still listed and sold as usual.

Worked example

A group with Safe on both sides, markup 3 %, shares at 100 %, over a 5-day window whose daily highs are 2.30, 2.20, 2.00, 2.45, 2.10:

base (lowest daily high) = 2.00      → Steam price 2.00
sell price               = 2.00 / 1.15 = 1.74
buy price                = 1.74 − 3 % = 1.69

The bot bids 1.69, lists at a Steam price of 2.00, and nets 1.74 per sale before the market moves.