Is Gamdom Rigged? How Its Provably Fair System Works, and Its Limits
Gamdom publishes a SHA256 hash chain for its Originals that lets anyone check a result wasn't changed after the round. Here is what that proves, what it can't, and what Gamdom's licence and terms actually say.
Key takeaways
- 01Gamdom says it generated “a chain of 10 million SHA256 hashes for each game” and plays it in reverse. It publishes each game's hash after the round, so you can check that results weren't changed.
- 02Provably fair shows that a result was fixed in advance. It doesn't tell you the RTP, it doesn't cover slots from outside studios, and it says nothing about withdrawals.
- 03In a December 2025 press release, Gamdom said all its Originals had moved to a 100% RTP. We could not confirm current per-game figures on gamdom.com.
- 04Gamdom is run by Moon Revolution Limitada (Costa Rica) under licence ALSI-152406043-FI4 from Anjouan, Union of Comoros. We found no official public register to check that number against.
- 05Gamdom's terms bar the United States, the UK and 35 other places. It is not on iGaming Ontario's or Alberta's list of regulated sites.
Short answer: for its own games, Gamdom publishes a hash chain that lets anyone check that results were fixed in advance and not changed afterwards. That is a real check, but a narrow one. It doesn’t tell you the RTP, it doesn’t cover slots from outside studios, and it says nothing about whether you’ll be paid.
What provably fair proves
| Question | Does provably fair answer it? | Why |
|---|---|---|
| Were results fixed before the round? | Yes | The hash of the end of the chain was published in advance, and each game’s hash links back to the one before it. |
| Can the site change a result after bets are in? | No, if the chain checks out | A swapped result would break the hash link to the previous game. |
| What is the RTP? | No | The payout rules set the RTP. Provably fair doesn’t measure it. |
| Are third-party slots covered? | No | Gamdom’s fairness page covers its own games only. |
| Will my withdrawal be paid? | No | That depends on the terms and the operator. |
How Gamdom says its provably fair system works
Gamdom’s fairness page describes a hash chain:
- “We have generated a chain of 10 million SHA256 hashes for each game, starting with a server secret that has been repeatedly fed the output of SHA256 back into itself 10 million times.”
- It publishes the SHA256 of the final hash for three games: Crash (starting at game 5,257,547), Roulette (from game 11,761,475) and Hilo (from game 18,975,566). Gamdom says publishing these prevents it picking “an alternate SHA256 chain”.
- “The game server is playing through this chain of hashes in reverse order, using these values to calculate the game results.”
- “We’re publishing a game’s hash immediately after the game ends.”
It links sample code for working out results in Crash, Roulette, Hilo, Dice, Plinko, Mines, Keno, Pocket Dice, Limbo, Blackjack and Twist. Its own summary: “results for all future games are already predefined … We cannot manipulate this chain of results without the public noticing it.”
The page describes the hash chain only. It doesn’t describe a seed that you supply yourself.
Gamdom’s FAQ says: “All of our original games are provably fair and the results can always be verified.” For everything else, it says Gamdom works with “licensed game providers” whose random number generators have been tested “by external and independent sources”. In other words, the slots and live games in Gamdom’s lobby are not covered by its provably fair checks.
How to verify a Gamdom round yourself
- Note the published hash for the game on Gamdom’s fairness page. This is the anchor at the end of the chain.
- Get the game’s hash for the round you played. Gamdom says it publishes it straight after the game ends.
- Run that hash through SHA256 with any SHA256 tool. Gamdom says the output should equal the previous game’s hash. Repeat this to walk back through the chain.
- Recalculate the result by putting the game’s hash into Gamdom’s sample code for that game. The result should match what you saw.
- Keep evidence if anything doesn’t match: the round ID, both hashes and screenshots. Raise it with Gamdom support.
The RTP question
Provably fair proves the draw wasn’t changed. The payout rules decide the long-run return.
In a press release dated December 10, 2025, Gamdom said it was “implementing a 100% Return to Player (RTP) rate across all Gamdom Originals”. It named Crash, Dice, Mines, Plinko, Roulette, Keno and Hi-Lo (release via PlayNewswire). A 100% RTP means no built-in house edge on those games. The release doesn’t give a start date, and Decrypt labels it sponsored.
We could not confirm current per-game RTP figures on gamdom.com, because its game pages did not load for us. Check each game’s info panel before you rely on the press release. Slots from other studios keep their own RTPs either way. Even a 100% RTP game can lose you money in a session, because RTP is an average over a very large number of bets.
Gamdom’s licence and where it operates
| Item | What Gamdom’s own pages say |
|---|---|
| Operator | Moon Revolution Limitada, Costa Rica, registration 3-102-903008 |
| Licence | ALSI-152406043-FI4, issued by the Government of the Autonomous Island of Anjouan, Union of Comoros |
| Restricted countries | 37 listed, including the United States and the United Kingdom |
| Governing law | Costa Rica, with Costa Rican courts having exclusive jurisdiction |
We looked for an official public register of Anjouan licences to check that number against, and did not find one. We report the licence as Gamdom states it.
Restricted countries. Clause 3.4 of Gamdom’s terms lists: Aruba, Austria, Australia, Belgium, Bonaire, Curaçao, Denmark, France, French Guiana, French Polynesia, Germany, Guernsey, Gibraltar, Greece, Hungary, Isle of Man, Iran, Jersey, Lithuania, Liechtenstein, Luxembourg, Malta, Martinique, Mayotte, Myanmar, North Korea, the Netherlands, Portugal, Puerto Rico, Réunion, Serbia, Slovakia, Slovenia, Spain, Sweden, the United States and the United Kingdom. The terms add that using “VPNs, proxies, or similar tools” to get around this can get your account restricted.
Canada. Canada isn’t on that list. Gamdom is not in iGaming Ontario’s directory or on Alberta’s registered sites list (both checked October 10, 2026), so it is not regulated in either province. See Are offshore gambling sites legal in Canada?
What provably fair can’t protect: withdrawals
Gamdom’s terms (last updated October 1, 2025) say:
- You consent to KYC checks “at Account registration or at any time thereafter, especially when specific financial thresholds are met”. These can include ID, proof of address and source of funds.
- Delays in providing documents “may result in withdrawal processing being paused until verification is finalised”.
- Complaints go to support@gamdom.com “to resolve the issue informally”. The terms are governed by Costa Rican law.
No Canadian regulator can step in. iGaming Ontario says it “has no legal relationship with unregulated igaming Operators” (iGO). BetGuard self-exclusion covers “all regulated igaming websites in Ontario” (iGO FAQs), which doesn’t include Gamdom. See Gambling withdrawal complaints in Canada.
If you need a break
Gamdom has a responsible gambling page. For free, confidential help in Canada, see Problem gambling help in Canada.
Checked October 10, 2026. This page explains what Gamdom publishes about itself. It is not legal advice and does not recommend any operator.
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Questions
Is Gamdom rigged?
For Gamdom's own games, it publishes a provably fair system. Results come from a pre-generated chain of SHA256 hashes, and each game's hash is published after the round, so anyone can check that results weren't swapped. That rules out changing a result after the fact. It doesn't tell you the game's RTP, and it doesn't apply to slots and live games from outside studios.
How does Gamdom's provably fair system work?
Gamdom says it started with a server secret and fed it through SHA256 10 million times to make a chain of hashes for each game. It published the hash of the final link for Crash, Roulette and Hilo. Games then play through the chain in reverse. Because each game's hash, run through SHA256, gives the previous game's hash, Gamdom can't swap in a different result without breaking the chain.
What is Gamdom's house edge?
In a press release dated December 10, 2025, Gamdom said it had moved all Gamdom Originals to a 100% RTP. It named Crash, Dice, Mines, Plinko, Roulette, Keno and Hi-Lo. A 100% RTP would mean no house edge on those games. We could not confirm current per-game figures on gamdom.com, so check each game's info panel.
Is Gamdom licensed?
Gamdom's terms say it is operated by Moon Revolution Limitada, a Costa Rica company, under licence ALSI-152406043-FI4 issued by the Government of the Autonomous Island of Anjouan, Union of Comoros. We did not find an official public register to check that licence number against.
Is Gamdom legal in Canada or the US?
Gamdom's terms list the United States among the places it does not serve. Canada is not on that list, but Gamdom is not in iGaming Ontario's directory or on Alberta's list of registered sites, so it is not regulated in either province.