Betting data glossary: the words in an odds feed, explained

Prices and probability

Odds

A bookmaker's price for an outcome: what you get back if it happens. Written as decimal, fractional or American odds, all three saying the same thing in different notation.

Decimal odds

The total return per dollar staked, stake included. 2.50 pays $2.50 for every $1, a profit of $1.50. The standard in Australia and in this feed's decimal_odds field.

Fractional odds

Profit to stake as a fraction: 3/2 means $3 profit for every $2 staked, the same as decimal 2.50. Common in the UK and in racing.

American odds

A signed number: +150 means a $100 stake wins $150; -200 means you stake $200 to win $100. The feed sends decimal prices; the converter turns them into American odds.

Implied probability

The chance a price would be fair at: one divided by the decimal price. 2.50 implies 40%. Add the implied chances of every outcome in a market and the total shows the bookmaker's margin.

Overround

How far a market's implied probabilities add up past 100%. Two sides at 1.90 imply 52.6% each, 105.3% together: a 5.3% overround.

Vig (vigorish, juice, margin)

The bookmaker's built-in edge, the same thing as the overround seen from the bookmaker's side. Lower vig means prices closer to fair.

Fair odds (no-vig price)

A price with the margin taken out, so the implied chances add to exactly 100%. The feed sends the inputs, Pinnacle and Betfair Exchange prices; four ways to compute your own.

De-vig

Removing the margin from a set of prices. The common methods are multiplicative, additive, power and Shin; they differ in how much of the margin they take off long-priced outcomes.

Consensus price

A single price summarising what the bookmakers think, margin still inside, such as the median of every book's price. One response holds every book you need to work it out.

Sharp bookmaker

A bookmaker with low margins that accepts large bets from winning customers, so its prices track the true chances closely. Pinnacle is the usual example and a common source for fair prices.

Soft bookmaker

A retail bookmaker whose prices lag the sharp market and whose margins are higher. Most Australian corporate bookmakers sit here, which is where price gaps appear.

Betting exchange

A marketplace where customers bet against each other and the operator takes a commission. Prices are set by backers and layers, which makes them a good guide to fair value. Betfair, Matchbook and ProphetX are in the feed.

Back and lay

On an exchange, backing an outcome bets that it happens; laying bets that it does not, taking the other side.

Prediction market

A venue trading contracts that pay $1 if an event happens, so a contract at 62 cents implies a 62% chance. Kalshi and Polymarket appear in the feed as bookmakers, their prices converted to decimal.

Favourite-longshot bias

The tendency of bookmakers to load more margin onto outsiders than favourites, so long prices are worse value than short ones. Some de-vig methods allow for it.

Markets

Market

One thing to bet on in a game, such as the winner or the total points, with a price for each outcome. In the feed each market has an ID and a key such as winner or total_points, and lists its outcomes, each with a price.

Head to head (moneyline)

Which side wins. Called the moneyline in the US. Market key winner in the feed, with sides home and away.

Line (spread, handicap)

A points start given to one side; the bet is whether they cover it. Market key handicap; each outcome's number is in its line, negative for the side giving the start.

Total (over/under)

Whether the combined score lands over or under a number. Market key total_points (or total_goals, total_runs), sides over and under, with the number in line.

1X2 (three-way)

Home win, draw, away win as three outcomes, standard in soccer. Market key result, with sides home, draw and away.

Alternate line

A line or total at a number other than the bookmaker's main one, with its own price. The feed returns each one as its own market, marked alternate, when you ask with alternates=true.

Main line

The line or total a bookmaker shows by default, usually the one closest to even money. In the feed, outcomes away from the main line are marked alternate: true.

Player prop

A bet on one player's statistic: disposals, try scorer, hits, passing yards. In the feed a prop is a market whose subject is the player, with a key such as player_disposals_over_under. Props in detail.

Team prop

A bet on a team statistic other than the main result, such as a team total. In the feed its subject is the team, as in team_points_over_under.

Period market

A market on part of a game: a half, a quarter, an innings. The market's period says which part, such as half_1 or quarter_2.

Futures (outrights)

A bet on a season-long result, such as the premiership winner. The feed prices games, not futures.

Multi (parlay, accumulator)

Several bets combined into one; every leg must win and the prices multiply. Called a parlay in the US.

Same game multi (SGM)

A multi whose legs come from one game. Books price these themselves because the legs are often related; multiplying the single prices overstates the payout.

Yes/no market

A market with two outcomes that are not sides, such as whether a player scores. In the feed, scorer markets end in _anytime with the single side yes, and others in _yes_no.

Strategy

Expected value (EV)

The average profit per dollar over many bets at a given price and chance: fair chance times price, minus one. Positive means the price is better than fair. +EV with the feed.

Positive EV (+EV)

A bet whose price is longer than the fair price, so its expected value is above zero. An edge over many bets, not a sure thing on any one.

Arbitrage (arb, surebet)

Backing every outcome of a market with different bookmakers at prices whose implied chances add to under 100%, so you profit whatever happens. Finding them in the feed.

Middle

Backing the over at one bookmaker's total and the under at a higher total from another, so both win if the result lands between them.

Closing line

The price just before the game starts, when the market is best informed. On Pro, snapshots=opening,closing returns each outcome's first and last recorded price for one event.

Closing line value (CLV)

How much better the price you took was than the fair closing price. Beating the close consistently is the standard sign that a strategy finds real value.

Line movement (steam)

A price or line changing before the game, often because informed money arrived. Steam is a sharp move across several books at once. Alerting on moves.

Kelly criterion

A formula for stake size from your edge and the price that maximises long-run growth. Most people bet a fraction of it. Calculator.

Bankroll

The money set aside for betting, from which stakes are sized. A unit is a fixed fraction of it, often 1%.

Line shopping

Checking every bookmaker's price before betting and taking the best. The whole point of a feed that lists every book's quote under one market.

Limiting

A bookmaker cutting the maximum stake it will accept from a customer it judges to be winning. Common for arbitrage and +EV bettors; read each book's terms.

Settlement

Settlement

Deciding whether a bet won, lost or pushed from the result. The feed's /v1/results grades each outcome it can settle from official results as won, lost, void or dead heat.

Push

A bet that lands exactly on the line or total, so the stake is returned. Avoided by half-point lines such as 40.5.

Dead heat

Two outcomes tying where only one was expected to win, such as a drawn AFL match on a head to head. Bookmakers usually pay a share of the stake under their dead-heat rules.

Void

A bet cancelled and the stake returned, for example when a game is abandoned or a player does not take the field.

Finalised

A game whose result is official. The feed's status turns final, and /v1/results publishes the verdicts.

Suspended

A price temporarily withdrawn by the bookmaker, often during a big moment in play. The feed leaves it out of current prices; ask for snapshots and it shows as available: false with no price.

The feed

Odds API

A web service that returns bookmaker prices as structured data on request, so software can read them instead of a person reading a website.

API key

The secret string that identifies your account on every request, sent as Authorization: Bearer on every request. Keep it on your server.

Endpoint

One address in the API that returns one kind of thing: /v1/odds for games and prices, /v1/leagues for the league list, /v1/odds/history for price changes.

Rate limit

The most requests a plan may make per minute. Past it the API answers 429 with a retry-after header saying how long to wait.

Object

The unit this API bills by: one top-level item in a response, usually one game, whatever is inside it. How usage is counted.

Event ID

The feed's ID for one game, such as ev_t03024es3aee. The same game keeps it in prices, results and history.

Outcome ID

The ID of one side of one market, such as oc_f0a48xpz2qd0qt1h. It is the same at every bookmaker, so it is how you line the books up, and results use it too.

Bookmaker key

The key for one bookmaker, such as sportsbet or pinnacle, on each bookmaker in a response and in the bookmakers filter. All 42.

League key

The exact key for one competition, such as afl or champions_league. Looked up, never guessed. All 46.

Market key

The plain name of a market, the same in every sport: winner, handicap, total_points, player_disposals_over_under. /v1/markets lists them.

Pagination (cursor)

Large answers come in pages. Follow links.next, the full address of the next page, until it comes back null.

Polling

Asking the API again on a timer to see what changed. About every five minutes suits this feed, since prices refresh about that often.

WebSocket

A connection the server pushes updates down, so you need not poll. On Pro the feed streams snapshots this way at /v1/stream/odds, every 15 seconds.

Stale

A price that has not been seen for a while. The feed holds back any price not seen for ten minutes instead of serving it as current.

Observed at

When a price was last seen at the bookmaker, on every quote as observed_at, in UTC. Show it, so readers know how fresh a price is.

OpenAPI specification

A machine-readable description of every endpoint, parameter and field, which code generators and AI tools can read. The spec.

llms.txt

A plain-text file at a site's root summarising it for language models, with links to fuller text. Ours.