What is a random number generator?

An RNG is a computer algorithm that generates random sequences of numbers to determine game outcomes. It ensures that every slot spin, card deal, or roulette spin is completely random and independent of previous results.

Are online casino games truly random?

Yes, at licensed casinos. RNG software is regularly audited by independent certification agencies like eCOGRA, iTech Labs, and GLI to verify true randomness and published RTPs.

Can casinos adjust the RTP?

Operators can choose from different RTP versions of the same game offered by providers, but they cannot manually adjust outcomes during play. The RTP setting must be disclosed and audited.

What is the difference between theoretical and actual RTP?

Theoretical RTP is the mathematically calculated long-term average. Actual RTP can vary significantly in the short term. Over millions of spins, actual RTP converges toward theoretical RTP.

How do casinos make money?

Through the house edge built into every game. A 4% house edge means the casino keeps R4 of every R100 wagered on average. This works reliably over millions of bets across thousands of players.

Are live dealer games more trustworthy?

Live dealer games use physical cards, wheels, and dice — you watch the action in real-time via video stream. OCR technology reads the results digitally. The transparency is appealing, but RNG games at licensed casinos are equally fair.

How Online Casinos Work | Behind the Scenes 2026

Random Number Generators (RNG)

Every outcome in an online casino game is determined by a Random Number Generator — a sophisticated algorithm that produces millions of random numbers per second. When you press "Spin", the RNG has already determined the outcome. The spinning animation is purely visual entertainment.

This ensures every result is truly random, independent, and impossible to predict. Licensed casinos must have their RNG software audited and certified by independent laboratories like eCOGRA, iTech Labs, and GLI. These audits verify that the theoretical RTP matches the actual results over millions of game rounds.

The House Edge

Every casino game has a mathematical advantage built in for the operator — this is the house edge. For slots, it's expressed as 100% minus the RTP (e.g., a 96% RTP slot has a 4% house edge). For blackjack, it's around 0.5% with perfect strategy. For roulette, it's 2.7% (European) or 5.26% (American with double zero).

This edge ensures the casino profits over millions of bets, even though individual players can and do win. The key insight is that the house edge works over the long term — in any single session, your results can vary wildly from the theoretical expectation. This is variance, and it's what makes gambling exciting.

Software & Technology Stack

🖥️ Game Providers — Companies like Pragmatic Play, NetEnt, Evolution, and Microgaming develop the games. A single casino may host games from 30-80 different providers, each with their own RNG and certification.
🔧 Platform Software — The casino's backend manages player accounts, deposits, withdrawals, bonuses, and responsible gambling tools. Major platform providers include SoftSwiss, EveryMatrix, and White Hat Gaming.
🔒 SSL Encryption — 256-bit SSL encryption (the same used by banks) protects all data transmission between your device and the casino's servers.
💳 Payment Processing — Secure payment gateways handle deposits and withdrawals across multiple methods. Licensed payment service providers ensure funds are protected.
📱 HTML5 Technology — Modern games are built in HTML5, meaning they work on any device (desktop, tablet, phone) without plugins or downloads. No Flash required.
📡 Live Streaming — Live dealer games stream from professional studios using multiple HD cameras, OCR (Optical Character Recognition) technology reads physical cards and wheel results, converting them to digital data.

Licensing & Regulation

Legitimate online casinos are licensed by regulatory authorities. The licence requires regular audits of game fairness, financial reserves to cover player balances, responsible gambling measures, data protection compliance, and anti-money laundering procedures.

Major Licensing Authorities

🇲🇹 Malta Gaming Authority (MGA) — Gold standard. Strict player protection and fund segregation.
🇬🇧 UK Gambling Commission (UKGC) — Strictest in the world. Comprehensive player protection.
🇨🇼 Curaçao eGaming — Most common for international casinos. Lower barrier to entry but still provides oversight.
🇿🇦 SA Provincial Boards — Local regulation for South African licensed operators like Betway and Hollywoodbets.

Unlicensed casinos have none of these requirements and should be avoided. Check our blacklisted casinos page for operators we recommend avoiding.

The Business Model

Casinos make money through the house edge across millions of bets. They don't need to cheat — the mathematics guarantees long-term profitability. A casino with R10 million in monthly handle (total bets) and an average 3% house edge earns approximately R300,000 in gross gaming revenue.

Bonuses are marketing costs designed to attract and retain players. The cost of generous bonuses is offset by the lifetime value of retained players. This is why wagering requirements exist — they ensure the casino recoups its bonus investment before players can withdraw. Understanding this dynamic helps you evaluate which bonuses offer genuine value.

Frequently Asked Questions

Written by

David Gillespie

Casino Technology Writer

David demystifies casino technology and business models to help SA players make informed decisions about where and how they play.

How Online Casinos Work: Behind the Scenes