What is an RNG
In online gambling, an RNG is the engine that produces the underlying random sequence used to determine the outcome of every slot spin, card draw, or roulette result. Modern RNGs are pseudo-random: deterministic algorithms whose output passes statistical tests for randomness over very large samples.
RNG output is mapped to game outcomes by the game’s mathematical model. A 5-reel slot maps the RNG sequence to symbol positions on each reel. A blackjack RNG maps to card deals from a shuffled deck. The randomness lives in the RNG; the payout structure lives in the game model.
RNG certification
Reputable RNGs are tested and certified by external testing laboratories. eCOGRA, Gaming Laboratories International (GLI), BMM Testlabs, iTech Labs, and SIQ are the most widely recognised. Certification involves statistical testing across large output samples, code review of the RNG implementation, and verification that the RNG cannot be predicted, manipulated, or biased.
For regulated markets, RNG certification is a licensing prerequisite. Operators and game providers cannot operate without proof of certified RNG from an accredited lab.
RNG vs provably fair
Traditional RNGs are ‘fair because a lab certified them’. Provably fair systems, used primarily in crypto casinos, are ‘fair because each round can be independently verified after the fact’. Both approaches produce statistically random outcomes; the difference is how that randomness is proven.
In the regulated B2B casino market, certified RNG remains the standard. In crypto-native casinos, provably fair is the norm. Some platforms now combine both.
Frequently asked questions about What Is an RNG in iGaming?
Not in a certified game. The RNG is sealed within the game build, audited by the testing lab, and tamper-evident. An operator that attempted to interfere would invalidate the certificate and lose its licence.
True random uses physical entropy sources (atmospheric noise, hardware RNG chips). Pseudo-random uses deterministic algorithms seeded with entropy. Certified iGaming RNGs are pseudo-random but engineered and tested so the output is statistically indistinguishable from true random.
Most jurisdictions require annual recertification of RNG implementations. Material changes to the algorithm or seed mechanism require an immediate re-test.