Gambling terms, explained straight

Online Gambling & Industry

RNG slots

RNG slots are online slot games that use a random number generator to decide each outcome, so no two spins are linked or predictable.

Also called
Random slots
Regulation
UK Gambling Commission requires outcomes to be acceptably random 2
Applies to
Online reel-based casino games including those with non-traditional reels 1

Key points

  • An RNG uses a seed value and algorithms to generate numbers without a predictable pattern 4.
  • Each spin is independent of previous spins; the RNG runs continuously 4.
  • The UK Gambling Commission’s Remote Technical Standards require RNG outputs to be acceptably random 3.

Where this term is used

Not the same as

  • RNG meaning — the general term for the random number generator itself, not specifically slot games
Online RNG certification The process of testing and verifying that an RNG meets regulatory standards for randomness. Online Rakeback slots Slot games that offer a rebate on losses or a percentage of the house edge back to the player. Online Curacao gaming licence A Curacao gaming licence is a regulatory permit issued by the government of Curaçao Online iGaming iGaming is any form of gambling where a player places wagers or plays games of chance over a digital network rather t… Online GLI certification GLI certification is the official confirmation Online Rakeback poker In online poker, rakeback is a rebate

Sources

  1. Online games design and reverse withdrawals gamblingcommission.gov.uk Defines slots as reel-based games determined by RNG and states the scope of application.
  2. Regulatory returns guidance - 2 - Random number ... gamblingcommission.gov.uk Defines the requirement for outcomes to be acceptably random.
  3. Guidance to licensing authorities - RTS 7 – Generation of ... gamblingcommission.gov.uk Provides guidance on RNG generation and testing standards.
  4. Ensuring Fair Play with RNG Testing and ... ecogra.org Explains how RNGs use seed values and algorithms, and that each spin is independent.

Sources are drawn from regulators, universities and published research, and each one is labelled with what it actually is — a preprint is not called a paper. Bookmaker and affiliate pages are never cited here, because a page that sells betting is not a neutral authority on it.

Written and maintained by Ellis Warrender, writer and maintainer.

Last updated 28 July 2026. Spotted an error? Tell me and it gets fixed and logged on the corrections page.