How to Build a CS2 Price Alert Bot

A CS2 price alert bot can read the all-item GET /v1/prices/latest snapshot, select exact items or variants, and evaluate fresh marketplace asks or bids against stored rules.

The alert definition should name both the price field and source set. An ask-below alert watches acquisition listings; a bid-above alert watches an immediate-sale quote. These are different signals.

Data inputs for price alerts#

• Current ask, bid, ask_volume, and bid_volume fields across six marketplaces, with the source-specific exceptions documented below.
• updated_at and collected_at on each source row for freshness decisions.
• Supported phases and tiers under variants, with stable version codes and full variant names.
• Historical OHLC from December 24, 2025 for moving thresholds, high/low breakouts, or change calculations.

Current prices generally refresh every ~5-10 minutes. CSFloat bids refresh every ~10-30 minutes depending on liquidity. Polling more frequently than the underlying source cadence does not create a new observation.

Mapping rules to the data#

Fetch the current snapshot on a server, locate each rule by exact market_hash_name, and then choose the requested source and field. Compare collected_at with the snapshot's response_time to reject quotes older than the rule allows.

Keep alert state under the full item or variant identity plus source and field. This prevents a Phase 2 ask rule from sharing state with the base Doppler item or with a bid rule. For percentage changes, compare observations with known timestamps or use OHLC buckets instead of treating a long monitoring outage as one short-period move.

Applicable endpoints#

Alert limits#

• Skinport has no current bid. CSFloat and C5Game have no bid_volume, so rules requiring executable quantity cannot use those source rows.
• A current ask is one observed listing floor, not a completed sale or a reservation. It can disappear before the alert is acted on.
• Missing and null values should leave a rule unevaluated. Treating them as zero produces false price-drop alerts.
• A crossed bid and ask can reflect asynchronous observations. Discard the crossed pair for spread alerts instead of emitting a negative-spread event.

For sale-confirmed events, use the price and sale-volume spike method instead of current listing volume.