Random number generators

I've always wanted to know what really happens behind the scenes of online slots and card games. Why do some games feel fair while others seem suspicious? The answer lies in something called a Random Number Generator—or RNG. It’s the invisible system that decides your spin, your dealt card, or your roulette result.

In South Africa’s top online casinos, RNGs are used in virtual slots, blackjack, roulette, and other digital games. These tools ensure that every outcome is truly random and can't be influenced by the casino or players. They’re also audited regularly by independent agencies, which helps keep gameplay transparent and fair.

In this guide, I’ll explain how RNGs work, why they matter, and how you can make sure the casino you choose uses certified, fair systems. If you’re playing online, understanding this could save you time, money, and frustration.

By Adiela de Bruyn - Last modified 2025/03/19 - Estimated reading time: 6 minutes.

» Aspects that control the gameplay of online casino games
» How RNGs Work
» How Casinos Use Random Number Generators
» Proving the Fairness of a Random Number Generator
» Conclusion
» Frequently Asked Questions About RNG (Random Number Generator)

How RNGs Work

Random Number Generators (RNGs) are the backbone of online casino games, ensuring each outcome is random and fair. These algorithms produce sequences that lack any pattern, making game results unpredictable and unbiased.

Every time you press 'spin' or 'deal', the RNG generates a random number. That number corresponds to a specific outcome, whether it's a reel combination or a card dealt. The result is instant and independent from the previous round.

How an RNG Produces Numbers Randomly

The system keeps running in the background, creating numbers every millisecond. When you interact with the game, it stops at one number and translates it into a game result. No two outcomes are related, and the timing of your click matters.

This randomness is also used in fields like simulations and cybersecurity, proving just how reliable the method is. In online gambling, it keeps things transparent and gives every player a fair shot.

Pseudo-random Number Generator (PRNG)

Most online casino games use PRNGs. These rely on algorithms and a seed number to generate random-like sequences. Though the process is digital, it's extremely hard to predict without deep technical access.

Because it doesn’t rely on physical input, the PRNG can run indefinitely. It’s also why regular audits and certifications are critical—to ensure no one tampers with the logic or outcome.

True Random Number Generator

Some platforms use hardware-based RNGs, also called True RNGs. These depend on physical events like radioactive decay or atmospheric noise. Because these events are impossible to replicate, the results are 100% random.

These RNGs are more secure but are typically used in specialized scenarios or higher-security environments, not standard online slots.

How Casinos Use Random Number Generators

In most online casinos, RNGs are used in virtual games that don’t involve a live dealer. Think slots, video poker, scratch cards, and many table games. The RNG runs every second, converting outputs into game symbols or card values.

The idea is to replicate the feeling of unpredictability you'd find in a real casino. You can’t control the results—but neither can the operator. As long as the game is certified and tested, it’s a level playing field.

Is hacking possible? In theory, yes—but it's very unlikely. It would require breaking through advanced encryption and gaining access to the game’s core software, which is monitored by third-party testing labs.

Proving the Fairness of a Random Number Generator

Before a game goes live, its RNG software is thoroughly tested. Regulators and third-party testing labs ensure the numbers generated follow expected statistical patterns and can’t be manipulated.

Most online casinos in South Africa rely on independent organizations to provide certification. These include:

eCommerce Online Gaming Regulation (eCOGRA)

eCOGRA is well-known in online gambling. It tests both the games and the casinos that host them. The presence of their seal means the site meets international standards for fairness, safety, and transparency.

Gaming Labs International (GLI)

GLI works with regulators in over 560 jurisdictions. Their role includes auditing games, verifying RNG integrity, and ensuring platforms meet technical compliance. A GLI badge shows deep-rooted trust in the platform’s fairness.

Technical Systems Testing (TST)

TST is particularly trusted in South Africa. They verify RNGs, review payout claims, and monitor entire game libraries. Their Total Gaming Transaction Review checks every result for transparency and statistical accuracy.

Conclusion

Online casino fairness comes down to two things: certified RNG software and transparent testing. Without these, it’s hard to trust that the games you’re playing are fair.

I always recommend choosing licensed casinos that publish their testing certificates. Look for seals from eCOGRA, GLI, or TST in the site’s footer. These aren’t just badges—they’re signs of credibility and fairness.

Remember, RNGs keep the gameplay random, but playing smart and responsibly is still on you. Choose your games wisely, know their variance and RTP, and always stick to platforms that value transparency.

Frequently Asked Questions about RNG Fairness

What does RNG mean in online casinos?

RNG stands for Random Number Generator. It’s a system that makes sure every game round has a completely random and fair result. I’ve seen how it works behind the scenes—each spin or card draw is based on a number generated by an algorithm that can’t be predicted or tampered with.

Can I trust RNG games at South African online casinos?

If the casino is licensed and certified, then yes. I only recommend platforms that have been tested by independent agencies like eCOGRA, TST, or GLI. These third parties check that the RNG software works fairly and hasn’t been altered to reduce your chances.

What’s the difference between PRNG and True RNG?

PRNGs (pseudo-random number generators) use algorithms to produce random results, while True RNGs use physical processes like atmospheric noise. Most online casino games use PRNGs because they’re reliable and easy to test, though True RNGs are more secure and unpredictable.

How do I check if a game is fair?

Fairness usually comes down to two things: the game's RTP and independent certification. I always check the footer of the site for seals from testing labs. You can also view the game’s info screen—it often lists the RTP and software provider, which helps confirm it’s genuine.

Can RNGs be rigged by online casinos?

In theory, it’s possible. But licensed casinos that want to stay in business don’t take that risk. Audits and real-time monitoring make it almost impossible without getting caught. That’s why I avoid any site that doesn’t show proof of testing or licensing.

Do live dealer games use RNGs?

No, live dealer games don’t use RNGs. The outcomes come from real-time dealing by human croupiers. That said, RNGs power other features like game timers or bet placement in the background, but not the actual card or roulette outcomes.