The RNG acronym stands for ‘random number generator’ or ‘random number generation’. In online casino games, it usually refers to software, or sometimes even hardware, that continuously produces unpredictable sequences of values, forming the raw output that every game outcome is built from.
RNG decides which outcome occurs in a single round. It has no bearing on a game's long-run payout rate – that's the role of Return to Player (RTP), a separate percentage built into the game's mathematical model.
Because RNG and RTP govern different properties – unpredictability versus long-run payout – they are developed and certified independently. Each is assessed by testing labs against the statistical and technical standards of the regulated market that a game serves.
This guide covers how RNG works, where it applies across casino game types, and what operators should verify in a provider's implementation.
RNG is applied across three distinct layers of iGaming products, each with its own scope, testing requirements, and – in most cases – its own proprietor.
Depending on the use case, RNG may sit with the game provider, the casino operator, or a platform supplier – and may also power promotional draws or other auxiliary randomisation outside the game itself.
The most common use of RNG in iGaming is to determine the outcome of online casino games. Essentially, RNG is an algorithm embedded in the game software. It continuously generates random numbers, while the game's rules convert those numbers into the outcome of each round.
The algorithm usually runs as part of the game engine on a remote game server hosted by the game provider or a third party. Once there, the RNG cannot be influenced during normal gameplay.
RNG does not only determine the outcome of the main game: it may also control bonus triggers, free spins, random multipliers, prize selection, or mystery rewards.
These mechanics still operate within the game's mathematical model, including its probability, payout rules, and feature frequency. The exact implementation depends on the game provider and the individual game.
RNG is also used outside the game itself. Jackpot solutions may rely on a separate RNG implementation to determine when a jackpot is triggered, which prize tier is awarded, or which eligible player receives the prize.
Whether it is a local or network jackpot, the random selection always follows predefined campaign rules and eligibility criteria. The jackpot supplier is responsible for the underlying jackpot logic, campaign management, audit controls, and its own RNG implementation, which operates independently from the RNG used in the game itself.
There are two categories of random number generators relevant to iGaming infrastructure decisions: Pseudo-Random Number Generators (PRNGs) and True Random Number Generators (TRNGs).
While both produce unpredictable numerical values, they work in different ways: in online casino software, PRNGs are the most common choice because they generate results quickly and consistently for every game round; TRNGs, on the other hand, rely on physical sources of randomness and are less common in standard online casino games.
In both cases, the numerical output is converted by the game's logic into the final game outcome.
PRNG is the default choice for standard online casino software because it is fast, scalable, and can support thousands of game rounds simultaneously. Hardware-based random number generators – also known as physical entropy sources – cannot keep up with that volume.
A PRNG generates a numerical sequence from an initial seed value. The seed determines the starting point, while the deterministic algorithm continuously produces new values by updating its internal state. The game logic then maps those values to game outcomes, such as reel positions, card draws, or roulette numbers.
Their reliability, however, depends on more than the algorithm itself. Secure seed management, protected internal state, controlled software versioning, and strict access controls help maintain the integrity of the implementation and are key areas assessed during independent certification and testing.
Importantly, the seed does not determine a game's Return to Player (RTP), payout structure, or available wins. Those are predefined by the game design. The PRNG typically operates within the game provider's software or on a remote game server.
Unlike a PRNG, a True Random Number Generator (TRNG) relies on physical entropy rather than a deterministic software algorithm. It uses hardware to measure unpredictable physical events and converts them into random numbers.
Because TRNGs require dedicated hardware, they are less common in standard online slots and virtual casino games. Instead, they are more likely to be used in specialist gaming hardware, lottery systems, security components, or hybrid gaming architectures where physical entropy provides an additional source of randomness.
RNG certification is one of the clearest due diligence checkpoints when evaluating a game provider or platform partner. RNG audits confirm that each game’s random number generator meets the statistical and technical requirements of a given regulated market – and it is frequently the first thing a licensing body or a cautious operator will ask to see.
Let's delve deeper into the details and find out who provides these certificates and how to obtain them.
Knowing the shape of the RNG certification process tells you which questions to ask during due diligence, and which documents to expect a provider to produce on request:
RNG is a core, compliance-critical component of every regulated casino game, and certification is what proves it functions as intended. For operators, that proof underpins licensing eligibility, player trust, and dispute resolution. For providers and platform suppliers, making it visible – documenting how RNG is implemented across game outcomes, bonus mechanics, and jackpot logic – is what serious partners rely on when evaluating a provider.
Understanding where RNG sits in a product – game engine, bonus layer, or jackpot aggregator – and who certified it, gives operators a clearer basis for partner evaluation, market entry decisions, and regulatory conversations.
