A/B test
#Splitting traffic between two versions of a page or ad and keeping the one that wins on a metric you picked before the test started.
Picking the metric after you've seen the results is called astrology.
See also: Conversion rate
139 terms from slot math, affiliate deals, media buying, compliance and tech, each in one plain sentence plus a note from the margin. Filter by your job, jump to a letter, or link a colleague straight to the word they keep getting wrong.

Splitting traffic between two versions of a page or ad and keeping the one that wins on a metric you picked before the test started.
Picking the metric after you've seen the results is called astrology.
See also: Conversion rate
A partner who sends players to an operator and gets paid per player (CPA), as a share of revenue (RevShare) or a mix of both.
The only people who read bonus T&Cs for fun.
See also: CPA, RevShare, Hybrid deal
A platform that bundles games from many studios behind one integration, so an operator signs one contract instead of hundreds.
One API, thousands of slots, one very tired integration team.
See also: RGS
The checks an operator must run on deposits, withdrawals and source of funds so gambling can't be used to clean money.
Why “I'd like to deposit a suitcase” gets a phone call.
See also: KYC
The free way to get sweepstakes entries (often a mailed-in request) that keeps a US sweepstakes casino a sweepstakes and not a lottery.
The postcard that holds a whole business model together.
See also: Sweepstakes casino
An optional extra stake on top of each spin that raises the chance of triggering a feature.
Paying for the window seat. Sometimes the view is better.
See also: Enhancer
Revenue divided by the number of active players over a period.
The number finance quotes when it wants to sound calm.
See also: LTV
Repeating rounds automatically with the same bet. Some regulators restrict it; the UK switched it off for online slots in 2021.
The Auto modes in our Originals come with a stop-on-profit limit; dice and limbo add stop-on-loss.
B2B companies sell games or tech to operators. B2C companies run the casino and face the players.
We're B2B. Our only player is Chip, and he never cashes out before 2×.
See also: Operator
The main game mode, before any free spins or bonus round.
Where players spend most of their time, so it can't feel like a waiting room.
See also: Bonus round
What a referred player must do (deposit amount, wagering, active days) before an affiliate's CPA is paid.
Read it before you celebrate an FTD.
A separately priced way to play the same game (base, enhancer, bonus buy), each with its own math and its own RTP.
Vampir has five. Uncle Vlado has opinions on all of them.
A celebration screen for wins above a set multiple of the bet, usually in tiers like big, mega and epic.
Our Originals roll it out from 10× upwards. Your neighbours will hear about it.
Paying a fixed multiple of the bet (100×, for example) to start the bonus feature straight away. Not allowed in some markets, the UK among them.
Skipping the queue, priced in multipliers.
See also: Bet mode
A special mode (free spins, pick-me, wheel) triggered during play, usually where the big wins live.
The reason anyone tolerates the base game.
See also: Free spins
Stake Engine's pre-generated rounds: every possible outcome of a bet mode written out with its events and given a weight. The RGS picks one per bet.
Every possible night shift, written down before anyone spins.
See also: Lookup table, Stake Engine
The share of visitors who leave without interacting with the page.
Usually a page-weight problem wearing a copy-problem costume.
What it costs, on average, to win one new depositing player.
Compare it with LTV, not with your hopes.
See also: LTV
Winning symbols disappear and new ones drop in, so a single bet can produce a chain of wins.
Vampir's bats gain +1 for every tumble they survive.
A refund of part of a player's losses over a period, paid as cash or as bonus money.
A consolation prize with a marketing budget.
A network of servers around the world that serves your files from somewhere close to the visitor.
Physics is undefeated; a CDN just moves the files closer.
An accredited testing house (GLI, BMM, eCOGRA and iTech Labs are well-known names) that checks a game's RNG and math against a market's technical standards.
The exam where your RTP has to show its working.
A unique ID your tracker gives each click, carried through the landing page to the offer so a conversion can be matched back to it.
Lose it on the way and your best campaign looks like your worst.
Showing ad reviewers one page and real users another to slip past a policy. We don't build it, at any price.
If the reviewer can't see it, it shouldn't be live.
See also: Geo-swap
Wins for groups of touching symbols (side by side or above and below) instead of lines.
Rakia Lab pays in clusters on a 7×7 glass grid.
See also: Pay anywhere
The share of visitors who complete the next step: click, register or deposit. Always say which step.
“Our CR is 30%” means nothing until someone asks “of what?”.
See also: A/B test
Google's page-experience metrics with published “good” thresholds: LCP ≤ 2.5 s, INP ≤ 200 ms, CLS ≤ 0.1.
Green on a real phone beats green on your laptop.
See also: Lighthouse
A fixed fee per qualified new player, usually paid on a first deposit that meets the baseline.
Simple, until you read the baseline.
See also: Baseline, Hybrid deal
What you pay for each click, or for each thousand times the ad is shown.
CPM buys eyeballs. CPC buys fingers.
See also: CTR
A multiplier climbs from 1.00× until a random crash point. Cash out before the crash and you win the bet times the multiplier.
Our Rocket Chip has a 1% edge: the chance of reaching x is 0.99 ÷ x.
See also: Originals
The drop in an ad's performance as the same audience sees it again and again.
Why media buyers order creatives in packs of 50.
The button or line that tells the visitor what to do next. One per screen is plenty.
“Click here” isn't a CTA, it's a shrug.
Clicks divided by impressions.
High CTR with a low CR usually means the ad promised something the page didn't.
See also: Conversion rate
Design that tricks people into something they didn't mean to do: fake scarcity, hidden opt-outs, confusing buttons.
Not in our toolbox. It's in the house rules.
See also: Fake urgency
A free version of a game with fake currency. Some regulators (the UK, for example) want age checks even before free play.
Every demo on this site runs on play money and nothing else.
A cap a player sets on how much they can deposit per day, week or month.
A seatbelt you fasten before the ride, not during.
See also: RG
A bonus that adds a percentage of the player's deposit, for example 100% up to a cap, usually with wagering requirements.
“100% up to €500” reads fast. The wagering requirement reads slower.
See also: Wagering requirement
The player sets a target and picks over or under; a random number decides. The multiplier follows from the win chance.
In our Hyper Dice: multiplier = 99 ÷ win chance, from 1.0102× up to 9,900×.
The final screen of a playable or video ad, carrying the call to action.
The last three seconds that pay for the first twenty.
See also: Playable ad
A bet mode that costs more per spin in exchange for better feature odds.
Vampir's Night Owl costs 2× and roughly doubles the chance of free spins.
Affiliate earnings divided by clicks sent. The quickest way to compare offers.
The number affiliates check before their coffee.
The most an operator could pay out on a single round, which is why max-win caps exist.
Your risk team's favourite bedtime story.
Invented time or stock pressure: countdowns to nothing, “only 3 bonuses left”, fake live-winner feeds.
We removed the timer. It wasn't counting down to anything.
See also: Dark pattern
A bonus round of spins that cost nothing, often with extra mechanics like multipliers or sticky wilds.
Vampir's free spins are one night shift, from 21:00 to 07:00.
See also: Retrigger
A new player who makes a first deposit. The number most affiliate deals revolve around.
Celebrated by affiliates like a birthday.
The steps from first impression to deposit: ad, pre-lander, landing page, registration, deposit.
Every step leaks. Our job is smaller holes.
See also: Pre-lander
A one-page summary of a game: rules, RTP, volatility, max win, bet modes, features and media.
We built a whole page of them. You're one click away.
The country or region traffic comes from or is aimed at. Offers, payouts and rules all change by geo.
The answer to “is this allowed?” always starts with “which geo?”.
One page that shows market-specific content (language, currency, licence lines, T&Cs) based on the visitor's country or a URL parameter.
One build, many markets, and the same page for reviewers and users in each one.
See also: Cloaking
Total bets minus total wins, before bonuses, taxes and costs.
The number before everyone takes their cut.
See also: NGR
The two currencies of a US sweepstakes casino. Gold Coins are for fun only. Sweeps Coins come free (with GC packages or by free entry) and can be redeemed for prizes.
Buy the fun coins, get the other coins free. Lawyers spent years on that sentence.
See also: Sweepstakes casino, AMOE
Guess whether the next card is higher or lower; the multiplier grows with every right call until you cash out.
Our Hi-Lo Heist pays 0.99 ÷ chance on every guess.
How often a round returns any win at all, often written as “1 in 3”. It says nothing about how big those wins are.
A 1-in-2 hit rate full of 0.2× wins still feels like losing.
See also: Volatility
The share of money wagered that an operator actually kept over a period. Unlike house edge, it's measured, not designed.
House edge is the forecast. Hold is the weather.
See also: House edge
The share of each bet a game keeps on average: 100% minus RTP.
Ours is written in the rules, not hidden in the code.
See also: RTP
The web standard modern casino games run on: in the browser, on any device, no plugins.
No Flash. It's 2026.
An affiliate deal combining a CPA with a RevShare percentage.
A bird in the hand and a share of the bush.
Standard display ad sizes like 300×250, 728×90 and 160×600.
Twenty sizes by Friday? If it's Monday, yes.
Online gambling: casino, sports betting, poker, lotteries and their neighbours.
Also the word that ends small talk at airports.
The browser built into social apps that opens when someone taps your ad. It behaves differently from Chrome or Safari.
Test your page there, not only on your laptop.
A short game resolved in seconds: crash, mines, plinko, dice, scratch cards.
Fourteen of them are playable on this site.
See also: Originals
Pick numbers, a set of numbers is drawn, and the payout depends on how many you hit.
Star Keno draws 10 balls from 40; its High-risk paytables top out at 9,999.99×.
Identity, age and address checks an operator runs on players, usually before withdrawals.
The reason “just a quick withdrawal” takes a day.
See also: AML
The page a visitor reaches after the click, built for one action.
One offer, one promise, one button.
See also: Pre-lander
Permission from a regulator to offer gambling in a market (UKGC, MGA and Curaçao are familiar names). Game suppliers may need their own B2B licence too.
We're a studio, not a licensee. Your platform or partner holds the licence.
Google's tool that scores a page on performance, accessibility, best practices and SEO.
A score is a hint, not a KPI. Real phones decide.
See also: Core Web Vitals
The operator's game library screen, with tiles, categories and search.
Where your game has about a second to look interesting.
An ad audience built to resemble an existing list of users. Gambling targeting is restricted on many platforms.
Clone your best players? Only the adults, and only where the rules allow.
The list of book IDs, weights and payouts the RGS uses to pick a book for each bet.
Weights decide the odds. The books just tell the story.
See also: Books
What a player is worth over their whole time with an operator.
Everyone has a model. Few of them agree.
See also: CAC
A placeholder like {clickid} that a network or tracker swaps for a real value when the ad is clicked.
Get one brace wrong and your report fills up with literal {clickid}s.
See also: Click ID
The biggest payout a single round can produce, as a multiple of the stake.
Vampir: 25,000×, in every bet mode.
Someone who buys traffic and sends it to offers, earning on the gap between cost and payout.
A professional optimist with a spreadsheet.
See also: ROI / ROAS
Slots where the reel heights change every spin, so the number of ways to win changes too. “Megaways” itself is a trademark its owner licenses.
We build our own variable systems and leave the name where it belongs.
A grid hides mines. Every safe tile raises the multiplier; a mine ends the round. Cash out whenever you like.
In Gem Mines the payout is 0.99 × C(25,k) ÷ C(25−m,k).
The IAB standard API that lets an HTML ad talk to the app it runs in: when it's ready, when it's visible, how to open a link.
Use mraid.open(), not window.open(), or your CTA goes nowhere.
See also: Playable ad
A factor applied to a win. In instant games the multiplier is the payout itself.
In Vampir, bat multipliers add up; they never multiply each other.
Ads that look like content in a site's feed, sold by native networks.
Home of the “doctors hate him” headline. We write better ones.
In RevShare, a losing month (players won more than they lost) carried into the next month's balance. Some deals carry it, some reset it.
One lucky high roller can cost an affiliate two months.
See also: RevShare
GGR minus bonuses and, depending on the contract, taxes and fees. Most RevShare deals are paid on NGR.
Read your contract's definition. Then read it again.
See also: GGR
A small bonus given without a deposit, usually with strict wagering and a low cash-out cap.
Free, the way a free sample is free.
See also: Wagering requirement
A counter used in provably fair games so the same pair of seeds gives a fresh result every round.
The bit that stops yesterday's result from being today's.
See also: Provably fair, Seed
What an operator gives through affiliates: the player bonus plus the payout terms (CPA or RevShare, geo, baseline).
One casino can have five offers. Ask which one.
A page listing several offers so the visitor picks the one they like.
A buffet. Works best when the plates are actually different.
The company that runs the casino, holds the licence and pays players and affiliates.
The one whose name is on the T&Cs.
Casino-branded instant games (crash, mines, dice and so on), typically with a low house edge and often provably fair.
We made fourteen. Chip tested all of them. Mostly crash.
See also: Instant game
The document that describes a slot's math: reel strips or weights, paytable, RTP by feature, hit rate and volatility.
A game's birth certificate, with numbers.
See also: Simulation
Symbols pay when enough of them land anywhere on the screen, with no lines.
In Vampir, 8 or more of a symbol anywhere pays.
See also: Cluster pays
A pattern across the reels that a winning combination has to follow.
Thracian Gold uses 20 of them on a 5×3 grid.
The list of what each symbol combination pays.
Read it once and every game makes more sense.
A small script on a page that reports visits and events to an ad platform or analytics tool.
Great for data. One too many and your page loads like it's 2009.
See also: S2S
An interactive HTML5 ad the user can play for a few seconds before the call to action.
Under the size limit, over the fun limit.
A ball drops through rows of pegs, and the bucket it lands in sets the multiplier.
Neon Drop's edge buckets reach 289× on 16 rows at high risk.
A message from the operator or network to your tracker saying “this click converted”, with the click ID and payout.
The receipt for your traffic.
A short page before the offer page that warms the visitor up: a quiz, an article or a mini-game.
Ours are games, and honest about it.
See also: Landing page, Funnel
A prize that grows with every bet across a game or network until someone wins it.
Doesn't fit stateless platforms like Stake Engine.
See also: Stateless
A scheme that lets players check a result wasn't changed after they bet: the server commits to a hashed seed, the player adds a seed, and anyone can recompute the result afterwards.
Trust, but verify. Mathematically.
Ads delivered as browser notifications to people who once clicked “allow” on some site.
Cheap clicks. Check the quality before you scale.
A pop-up that reminds the player how long they've played and how much they've won or lost.
Not a buzzkill. A seatbelt.
See also: RG
The ordered list of symbols on one reel. The RNG picks a stop position on it.
Where volatility is quietly decided.
See also: Par sheet
The same game mechanic with new art, theme and sound, usually with retuned math.
Fast and fair, as long as you own the original.
See also: White-label
Showing ads to people who already visited your page or app.
The “you forgot something” of iGaming.
Landing the trigger again during free spins to win extra spins.
In Vampir, 3 or more coffins add 5 spins and the clock keeps running past 07:00.
See also: Free spins
An affiliate deal that pays a percentage of the net revenue from the players you referred, for as long as the deal says.
A slow-cooker deal. Patience pays, sometimes.
See also: NGR, Negative carryover
Tools and messages that help players stay in control: deposit limits, reality checks, time-outs, self-exclusion, helplines.
Not a footer. A feature.
See also: Deposit limit, Self-exclusion
The server that runs a game's outcomes and money calls for a casino: it takes the bet, decides the result and tells the wallet.
The game's brain lives here. The browser is just the face.
See also: Wallet, Stake Engine
The algorithm that produces the random numbers behind every outcome. Certified RNGs are tested by accredited labs.
The only truly neutral party in the casino.
See also: Certification lab
Profit (ROI) or revenue (ROAS) per unit of spend.
The only metric your finance team quotes back to you.
One complete play from bet to settlement, including every tumble and feature it triggers.
On Stake Engine, one round is one book.
See also: Books
The long-run percentage of stakes a game pays back. A 96% RTP returns 96 per 100 staked on average over a huge number of rounds, never per session.
Vampir: 96.50% in all five bet modes. Most of our Originals: 99%; the scratch card: 95%.
See also: House edge, Volatility
Tracking where conversions are reported straight between servers (see postback), not through a pixel in the browser.
Ad blockers can't eat it.
See also: Postback
A symbol that pays or triggers a feature wherever it lands, not on a line.
Our namesake. It's where the fun starts.
See also: Pay anywhere
Reveal hidden symbols; matching ones win. Online, the result is decided the moment you buy the ticket.
Holo Scratch: three of a kind wins, and a bonus seal multiplies it up to ×5.
The secret and public inputs a provably fair game combines to produce each result.
You see the hash first and the seed later. That's the whole trick.
See also: Provably fair, Nonce
A player's choice to be blocked from gambling for a set period, at one operator or across a national scheme.
A feature we'd rather see used than hidden.
See also: RG
Getting pages to rank in organic search.
Top lists live or die by it.
See also: Top list
Running a game's math millions of times in code to measure RTP, hit rate and the tail of the win distribution.
Our math department, checking the RTP for the 14th time.
One tracking link that routes each visitor to the best-fitting offer by geo, device or other rules.
Autopilot for offers. Check where it lands.
Casino-style games played for virtual currency that can't be cashed out.
All the spinning, none of the withdrawals.
See also: Sweepstakes casino
Stake's platform for third-party studios: you build the math (books) and the web front-end; it runs the RGS, reviews the game and publishes it.
Where our first slot went live.
A number for how widely results spread around the average. Higher means a bumpier ride.
Platforms often cap it. Players cap their patience.
See also: Volatility
A round that doesn't depend on any earlier round. Required by platforms that pre-generate outcomes.
Goldfish memory, by design.
See also: Books
A wild that stays in place for several spins.
Vampir's bats stay put for the whole free-spin shift.
See also: Wild
Extra tracking parameters (sub1, sub2…) added to a link to slice results by campaign, creative or placement.
The difference between “it works” and “this banner works”.
See also: Click ID
A US social casino model with two currencies, where one (Sweeps Coins) can be redeemed for prizes and there's always a free way to enter.
Legal status varies by state, so the exclusions list matters.
See also: Gold Coins / Sweeps Coins, AMOE
The rules of an offer: wagering, max bet, eligible games, expiry. Key terms belong next to the offer.
The small print that shouldn't be small.
See also: Wagering requirement
The rare, very large wins at the far end of a game's win distribution.
Where max-win frequency lives, and where reviewers look first.
See also: Max win
A ranked comparison of casinos or offers, usually with ratings and reviews.
Our ratings come with a methodology. Revolutionary, we know.
See also: SEO
Software such as Keitaro, Binom or Voluum that records clicks, routes traffic and matches conversions.
The single source of truth, if your postbacks work.
See also: Postback
A setting that speeds up animations without changing the odds.
Same math, less suspense.
Ads in the style of a regular person filming on their phone.
Authentic-looking, carefully scripted. Like reality TV.
Standard URL parameters (utm_source, utm_medium, utm_campaign…) that tell analytics where a visit came from.
Pass them through, or your analytics thinks everyone came from nowhere.
See also: Sub-ID
An operator's programme for high-value players: account managers, cashback, faster withdrawals.
Also the first place responsible gambling checks should look.
See also: RG
How a game's wins are spread: low volatility pays small and often, high volatility pays rarely but bigger. Same RTP, different ride.
Two 96% games can feel like a merry-go-round and a rollercoaster.
How many times a bonus (or bonus plus deposit) must be bet before winnings can be withdrawn.
35× on a €100 bonus means €3,500 of bets. Do the math before the player does.
See also: T&Cs
The operator's system that holds player balances. The RGS debits it for a bet and credits it for a win.
Where the play money ends and the real money starts.
See also: RGS
A finished product rebranded as yours: a single game or a whole casino platform under your name.
Our Originals: about 7 days from “that one” to “ours”.
See also: Reskin
A symbol that substitutes for others to complete wins.
Vampir's Bat Wild carries a multiplier too.
See also: Sticky wild
The point where a round ends because it hit the max win.
25,000× in Vampir. Then Uncle Vlado clocks off.
See also: Max win
No terms matched, so Chip took a nap. Try a shorter word, an abbreviation like “GGR”, or switch the filter back to all terms.
Now that we speak the same language, tell us what you want built.