Glossary

Definitions as this API uses them. For the concepts themselves — the maths and the CS2 domain — the marketing site's glossary and learn sections go deeper.

API terms

Envelope — the {data, meta} wrapper on every response. Details.

Cursor — an opaque forward pagination token from meta.next_cursor. Encodes a position within one specific ordering; never construct one. Details.

Slug — a lowercase hyphenated identifier (natus-vincere), usable anywhere a path id is expected on teams, players and tournaments.

Expansion — ?include=teams,tournament,odds on match detail, embedding related resources so one request replaces four.

Ticket — a 60-second credential from POST /v1/{game}/ws-token used to open a WebSocket, so the raw key never reaches a browser.

Quota vs rate limit — the quota is your monthly request allowance (hard cap); the rate limit is short-term throughput (a token bucket). Independent. Details.

Odds terms

eo_market — the served market line: a de-vigged aggregate of several bookmakers and exchanges, published only when at least two contributed. How it's computed.

eo_model — our own forecast. Not served until it clears its accuracy gate. Details.

De-vig — removing a bookmaker's margin so implied probabilities sum to 1 rather than more. Why our lines sum to ~1.0. Longer explainer: /learn/devig-fair-odds.

book_count — how many independent contributors priced an eo_market line. Never below 2.

Decimal odds — total return per unit staked. Implied probability is 1 / price. The only format served.

Closing line (is_closing) — the last price captured before scheduled_at. The standard benchmark for evaluating a forecast.

Brier score — mean squared error of forecast probabilities. Lower is better; 0.25 is the coin-flip baseline for a two-way market.

CS2 terms

ADR — average damage per round. Explainer.

KAST — share of rounds with a kill, assist, survival or trade. Units differ by endpoint: a 0–1 fraction on a player stat line, a 0–5 count on a round row. Explainer.

Rating — our own computed player rating. Not a third party's; don't compare absolute values across sources.

Opening duel (first_kills/first_deaths) — the round's first kill. Across a round's two team rows these sum to 0 or 1.

Trade — a kill avenging a teammate who has just died.

Eco / force buy — rounds bought below a full buy. Identified by a negative economy_level, which is a signed tier, not a missing value. Explainer.

Veto — the pick/ban sequence. The leftover map is a decider and has no acting team.

Glicko-2 — the rating system behind team ratings. The leaderboard sorts on rating − 2 × rd, discounting by uncertainty. Details.