When an operator offers a game to the public in a regulated market, players are trusting that the game behaves exactly as described: that results are random, that the RTP shown is real, and that nothing changes behind the scenes. That trust isn't built on a studio's word. It's built on independent testing against published technical standards. This article explains, in general terms, how that process works and what it actually checks.
A quick note on scope: we're describing how independent testing typically works across the industry. Specific requirements vary by jurisdiction and change over time, and operators and their regulators decide which standards apply in each market.
Why independent testing exists
A slot online game is software. Software can contain bugs, and in theory it could be written to behave unfairly. Regulators in many markets therefore require that games, and the systems that run them, are examined by an accredited independent testing laboratory before they go live. The lab acts as a technical referee between the studio, the operator and the regulator.
Testing typically covers three broad areas:
- The random number generator: is it genuinely unpredictable and statistically sound?
- The game maths: does the documented RTP match the real behaviour of the game?
- The game and platform software: does everything work as described, including error handling, history, disconnection recovery and player information?
The standards: GLI-11 and GLI-19 in plain English
Several organisations publish technical standards for gaming equipment and software. Two that are often referenced are known as GLI-11 and GLI-19, published by Gaming Laboratories International. Broadly speaking:
| Standard | General focus |
|---|---|
| GLI-11 | Gaming devices: requirements for game behaviour, RNG, payout and display of game information. Historically associated with land-based machines, but many principles carry across. |
| GLI-19 | Interactive gaming systems: requirements for online platforms and the games delivered through them, including player accounts, game history, communications and integrity of remote game play. |
These are not the only standards in use. Many regulators publish their own technical requirements, and other accredited labs test against them. Studios usually design to satisfy the common core of these documents, then address market-specific details as needed. SlotOnline Studio designs its games with these widely used standards in mind; formal testing for any given market is arranged through the relevant operators and accredited labs.
Testing the RNG
RNG evaluation is the foundation. A lab will typically:
- Review the algorithm and source code to confirm it uses a recognised, cryptographically appropriate generator and that it's seeded and cycled correctly.
- Run statistical test batteries on large volumes of output, checking for bias, patterns, correlations between successive values and uneven distribution.
- Check the scaling: how raw random numbers are converted into reel positions or feature choices. A sound generator can still produce biased results if the scaling is done carelessly, for example through a naive modulo operation.
- Confirm independence: one result must not influence the next, and game outcomes must not be affected by stake size, player history or time of day.
If you want a refresher on how the RNG drives each spin, see how slot online games work.
Verifying the maths
The studio submits a detailed maths document listing every reel strip, weight, pay value and feature rule, plus the calculated RTP. The lab then checks it in two ways:
- Independent calculation: the lab recalculates the theoretical RTP from the documented model, using its own tools.
- Empirical play: the actual game build is played, often in an automated way, over a very large number of rounds, and the measured return is compared against the theory within statistical tolerance.
Every RTP configuration of a game is usually verified separately. This is the stage where the work described in Inside Our Math Model really pays off: a clear, accurate maths document makes independent verification faster and far less painful for everyone.
Testing the game software
Beyond randomness and maths, labs examine whether the game behaves correctly and transparently. Typical checks include:
- The help screens and pay table accurately describe every feature and payout.
- The displayed RTP matches the configuration being run.
- Game history records each round correctly so disputes can be resolved.
- Interrupted games recover properly after a dropped connection, with the outcome preserved.
- Balance, stake and win displays are accurate and clearly visible.
- No misleading "near miss" animations or features that imply skill where none exists.
Version control and change management
Certification applies to a specific version of the software. Each approved build is identified, often with cryptographic signatures or hashes of the critical files, so operators and regulators can confirm that the game running live is the one that was tested. If the maths or game logic changes, the game typically needs to be re-submitted. This is one reason our technology stack keeps game logic strictly separated from presentation: we can fix a visual glitch without touching certified logic, though even then, change control rules still apply.
What testing does not guarantee
Independent testing confirms that a game is fair and works as documented. It doesn't make any game a good financial bet. A certified online slot with a 96% RTP still has a house edge, and short-term results are still unpredictable. Testing protects the integrity of the game; it doesn't change the odds in the player's favour.
How we approach it as a studio
Our process is built around making external testing straightforward:
- Server-side outcome generation, so the client only displays results.
- Simulation tools that run the real game logic, not a copy.
- Complete maths documentation for every RTP variant.
- Automated regression tests on every build.
- Responsible play features, such as reality checks, designed in from day one. See our responsible gaming page.
Our games are licensed only to operators outside Australia and are intended for adults 18+. On this site, every title runs in free-play demo mode only. To learn more about the studio, visit our about page or head back to the slot online studio home page.
18+ only. Our games are entertainment products. If gambling stops being fun, contact Gambling Help Online on 1800 858 858 (24/7, free and confidential).