RNG Certification Explained: What GLI and iTech Labs Test and What a Certificate Covers

Key takeaways

• An RNG produces the unpredictable numbers that decide game outcomes. Labs such as GLI and iTech Labs test that it is random and that the game follows its stated maths.
• A certificate applies to a tested version of a game or system under a specific standard. It is not a guarantee about an operator or a session.
• Provably fair lets players check individual results. Lab certification is an outside audit. The two answer different questions.

What an RNG is

Most digital casino games, from slots to table games, rely on a random number generator. In software this is usually a pseudo-random number generator: an algorithm that produces a sequence that is statistically indistinguishable from random, started from an unpredictable seed. Some systems add hardware entropy sources.

The RNG does not decide anything on its own. The game’s logic converts the numbers into outcomes, for example symbols on reels, using paytables and weightings. That mapping is what sets the game’s RTP and volatility.

What testing labs do

Independent laboratories, among them Gaming Laboratories International (GLI) and iTech Labs, test games and platforms against technical standards. These are often those required by a regulator, and different jurisdictions accept different labs.

Testing generally covers:

• Randomness. Statistical analysis of large volumes of outputs to look for patterns or bias.
• Game maths. Checking that the observed return matches the declared RTP and that the paytable and rules are implemented as described.
• Source and build review. Confirming that the version in production is the one that was tested.
• Security and integrity controls, such as how outcomes are generated server-side and how the game recovers from interruptions.

Passing produces a report or certificate for that game version. Studios typically publish which labs tested their titles, and operators often show certificate logos in the site footer.

What a certificate covers

A certificate is evidence that, at the time of testing, a specific game version met a specific standard. In practice it supports four claims: the RNG behaves randomly, the stated RTP is achieved over the long run, the rules work as described and the version can be identified.

What a certificate does not cover

• It does not predict or influence any single result. Short sessions can differ widely from the stated RTP.
• It is not an audit of the operator’s payments, customer service or finances.
• It does not apply to games that were not tested, or to modified versions.
• It does not replace a licence or the regulator’s oversight. See how licences differ.
• A logo is not proof. Certificates can be checked with the lab or the studio where verification is offered.

RNG certification versus provably fair

	Lab certification	Provably fair
Who checks	Independent laboratory	The player, using the algorithm
What is checked	Game version, RNG and maths	Each individual result
When	Before release and on changes	After each round
Scope	Games the lab tested	Games built on the scheme

The two are not competitors. Certification asks whether the game is designed and built fairly. Provably fair asks whether this particular result was altered after the player committed. Our guide to provably fair games explains the cryptographic method, including its limits.

Reading the claim

When an operator or studio says its games are certified, useful questions are which lab, which standard, which game versions and whether a report can be found. In crypto casino software, the studio’s game certificates and the platform’s own system certificates are separate things, and a claim about one does not cover the other.

Catalogue numbers such as RTP are listed in our slots catalog. For tools that help players keep control of their time and spending, see our responsible gambling page.

This article is information, not advice to gamble. You must be 18 or older.

FAQ

What is an RNG in an online casino game?

A random number generator is software that produces unpredictable outcomes, such as reel positions or card order. The game logic then maps those numbers to results according to its published rules.

What do GLI and iTech Labs do?

They are independent testing laboratories. They assess a game or system against technical standards and the requirements of a regulator, and they issue a report or certificate if it passes.

Does an RNG certificate guarantee that I will win?

No. It says the tested version of the game behaves as specified, including randomness and the declared return to player. It says nothing about any individual session.

How is RNG certification different from provably fair?

Certification is a one-off third-party audit of a game version. Provably fair lets a player verify individual results with cryptographic proofs, but it covers only the games that implement it.