Gamdom Crash audit: house edge up to 2.98%, not the advertised 1%

[DICE777]

On November 1, independent auditor ProvablyFair.org published an investigation into Gamdom's in-house Crash game. Gamdom advertises 99% RTP (1% edge). The report makes two separate claims: the maths in Gamdom's own published verifier pays less than that, and the seeding setup isn't provably fair as implemented.

1. The formula
The verifier busts ~1 round in 100 instantly at 1.00x, which already covers the full 1% edge. On top of that, every other crash point is shaved by an extra h/50 term. So a 2x target hits 49% of the time instead of 49.5%.

ProvablyFair's closed form for a target x:

Code:

RTP(x) = 0.99 * 0.98 * x / (x - 0.02)

• 1.5x → 98.33% (edge 1.67%)
• 2x → 98.00% (edge 2.00%)
• 5x → 97.41%
• 10x → 97.21%
• 1,000x → 97.02% (edge 2.98%)

I re-ran the formula and it matches. Tracker Gambafish recomputed 6.8M+ rounds of the current chain and got ~98.0% at 2x and ~97.3% at 10x.

Proposed fix: drop the h/50 term, keep the 1% instant bust → 99% at every target.

2. The "not provably fair" part
All 5,821 replayed rounds matched Gamdom's code, so results are reproducible. The issue is proof of fair selection:

• Crash moved to a new hash chain sometime between Oct 9 and Oct 26, with no new public commitment found and no announcement
• Both chains use the hash of Bitcoin block 339,300 (Jan 2015, originally Bustabit) as salt — known in advance, so in theory an operator could pre-compute candidate chains

The report says plainly this does not establish manipulation. It's missing proof, not proof of cheating. Standard fix: publish the commitment first, then salt with a future block's hash.

The $1.58M number
44-hour recording (Oct 26–28): 99,119 bets, 925 players, ~$850K wagered, blended return ~97.88%. Extrapolated Jan–Oct, that's ≈$1.58M (range $1.35M–$1.96M) in extra expected cost. It's an estimate, not proven losses, and assumes late-October volume held all year.

Zero Edge rakeback
Tested on one Unranked account: exactly 1% back per bet. On a 98% game that gets 2x to 99%, not 100%. Higher VIP tiers weren't tested.

Gamdom's response
Felix Romer called it "complete slander" and said Originals are "running above 100% rtp this year overall." @xet (Gamstat) argued $850K is a tiny sample and the live feed may be inaccurate. ProvablyFair's reply: sample size doesn't change odds the code sets — site-wide 100%+ on Originals and a 2.59% edge at 5x on Crash can both be true. As of Nov 2, no statement on the h/50 term, the new chain commitment, or refunds.

If you play it: save your bet history (stakes, targets, round IDs, rakeback), and note low targets lose less to the extra cut than 10x+.

Curious what people here think: is a formula-level edge above the advertised RTP worth a refund, even with rakeback on top? And should every crash operator be expected to publish a pre-committed chain + future-block salt by now?

Full write-up with tables, charts and sources (I write for this site, no affiliate links in the article): LootBonus - Gamdom Crash house edge audit

[Murat]

Yea, it would be great if you add their Twitter thread link <> https://x.com/provablyfairorg/status/2116988030292545641

Worth a read IMO!

[DICE777]

Yea, it would be great if you add their Twitter thread link => https://x.com/provablyfairorg/status/2110588030202545641

Worth a read IMO

Thanks for dropping the direct link to their X thread here! Having it right in the first reply is super helpful for anyone who wants to scroll through the raw screenshots and replies.

What really stood out to me in that thread is how Gamdom's team reacted - instead of directly addressing the `h/50` formula penalty or the missing pre-commitment for the new hash chain, they just brushed it off as "slander" and pointed to overall YTD RTP across all Originals.

Do you think they'll eventually quietly patch the crash formula, or just double down and ignore it?

[Fortify]

On November 1, independent auditor ProvablyFair.org published an investigation into Gamdom's in-house Crash game. Gamdom advertises 99% RTP (1% edge). The report makes two separate claims: the maths in Gamdom's own published verifier pays less than that, and the seeding setup isn't provably fair as implemented.

Frankly this explanation needs to be dumbed down a level further or better explained. I follow the general gist and supposedly "provably fair" games have been discovered as wrong in the past, but certain parts of the explanation - like how you split out the multipliers are hard to follow by somebody who doesn't do that much gambling on crash games. It seems like if they're going to go to all this trouble of rigging the game in a certain way they have screwed up royally by publishing all the outputs on the front page and not throwing in some basic fake bets to cover the scam up, but it's very possible. It's always concerning when the underlying mechanics are changed on a well established game like this, without good explanation and it's not usually to the benefit of the players when that happens. One or two extra percentage points over a year can equate to many millions of extra profit for the house, so they have every incentive to cheat. Rakeback also doesn't seem like a reasonable explanation because it should not factor in against the base calculation of a 1 percent edge.

I wonder if they're trying to refill their coffers after the confirmed Gamdom hack that took place earlier this month where they lost $3 million.

[el che]

Solid breakdown of the report man. Misrepresenting a 1% edge when the backend formula secretly takes off up to 3% at higher targets is false advertising and rakeback doesn't patch baseline math. Meanwhile switching hash chains quietly without an advance commitment and using an ancient 2015 block salt is amateur work.. it doesn't prove they cheated but it destroys their ability to prove they didn't. Calling it "slander" without addressing the h/50 term is just PR copium, so save your bet histories and keep an eye on them.

[Ayers]

Do you think they'll eventually quietly patch the crash formula, or just double down and ignore it?

Given how Gamdom team has simply dismissed this entire issue as slander, I don't think they will provide any official or public acknowledgment, nor will they patch formula.
However, it is entirely possible for them to silently tweak h/50 term or crash formula in backend!

I think these casinos never want to compromise their mainstream marketing or brand image.
They just keep ignoring such issue, and once pressure dies down, they quietly fix it.
Until on chain tracker bots begin providing continuous real time proof regarding this, i think they will remain in this defensive mode.

[Alphakilo]

So far, it's important players learn the importance of keeping bet histories because this audit from what I have seen shows poor cryptographic practices and the hidden math that's used to skim extra for house edge advantage.
Therefore, Gamdom failed to be true to their word and that shows that probably fair ain't really fair play in many ways as seen.

[Hispo]

So far, it's important players learn the importance of keeping bet histories because this audit from what I have seen shows poor cryptographic practices and the hidden math that's used to skim extra for house edge advantage.
Therefore, Gamdom failed to be true to their word and that shows that probably fair ain't really fair play in many ways as seen.

I mean... I am not an expert at provably fairness in gambling, but in order to run a proper audit by oneself, a typical gambler would need to have hundreds or even thousands of crash sessions before they can collect enough data to estimate the actual house edge being applied by the house, am I right?.

It would be much more time saving if casinos opted to develop free source originals, there would be no need for someone to run a time and resource consuming audit just to get an approximation on true values.

Though, we all know it is extremely unlikely casinos will adopt such a model.

[Cointxz]

First is Betfury and now Gamdom for declaring false house edge just to attract customers to play.

I hope there will be an action for this kind of misleading information as advertised on their games since no action has been done about this issue aside from minor noise that doesn’t affect the casino.

Operators just keep ignoring it as long there’s no repercussions with that deception.

[Darker45]

First is Betfury and now Gamdom for declaring false house edge just to attract customers to play.

I hope there will be an action for this kind of misleading information as advertised on their games since no action has been done about this issue aside from minor noise that doesn’t affect the casino.

Operators just keep ignoring it as long there’s no repercussions with that deception.

I'm sure there are more than just two casinos involved in this alleged kind of shady business. I guess this is the problem when online casinos aren't operating under a strict regulatory body or government.

If proven true, it won't be surprising considering how absolutely free they seem to be. Do the licensing authorities in Curacao or Anjouan even make audits, conduct random checking, do evaluations or review, and the like of the gambling platforms they issue licenses to? I doubt.

[yhiaali3]

I expect most casinos do this. It is true that the report clarifies that this does not necessarily mean there is direct manipulation or cheating of the results, but it prevents players from being able to self-verify the integrity of the game before playing.

Most casinos claim to be transparent and fair, but this is not the case; in reality, most lack transparency and impose hidden terms that negatively affect the fairness of the games.

[Cointxz]

First is Betfury and now Gamdom for declaring false house edge just to attract customers to play.

I hope there will be an action for this kind of misleading information as advertised on their games since no action has been done about this issue aside from minor noise that doesn’t affect the casino.

Operators just keep ignoring it as long there’s no repercussions with that deception.

I'm sure there are more than just two casinos involved in this alleged kind of shady business. I guess this is the problem when online casinos aren't operating under a strict regulatory body or government.

That’s correct, it’s true especially on the small to medium tier casino that has little reputation to protect.

If proven true, it won't be surprising considering how absolutely free they seem to be. Do the licensing authorities in Curacao or Anjouan even make audits, conduct random checking, do evaluations or review, and the like of the gambling platforms they issue licenses to? I doubt.

I doubt off shore regulators do an audit by themselves to casino they are giving license since this casino can always introduce new games right after they already acquired license.

However, it seems that license providers are already strengthening their security.

[mikel_012]

For transparency this is the link to the response from Felix Romer, the CEO: https://x.com/Romer/status/2117029060010266695

But it is interesting that in this page https://gamstat.io/casinos/gamdom/originals someone said they measured 56 million rounds of several Originals and all had a very low RTP. I do not know if this is real or there is a mistake, but for examploe a 99,31% declared in Blackjack vs 78% measured is a joke

[Betwrong]

On November 1, independent auditor ProvablyFair.org published an investigation into Gamdom's in-house Crash game. Gamdom advertises 99% RTP (1% edge). The report makes two separate claims: the maths in Gamdom's own published verifier pays less than that, and the seeding setup isn't provably fair as implemented.~

Thank you for posting this! I usually trust sites like Gamdom, with millions of users and tens of millions visitors per month. If they they say the house edge on Crash on their platform is 1%, I believe it is. But we need someone to check that for us from time to time. I'm not sure if can absolutely trust ProvablyFair.org. Are they really well-known in the industry? But still, someone has to check the fairness and publish about it. I'd love to see the reports by sites that officially check all that instead of someone who just decided to do it themselves.

[CryptoPlayGuide]

The simple version: a true 1% edge means reaching multiplier x with probability 0.99/x. At 2x, that's 49.5%. The ProvablyFair.org report says Gamdom's verifier gives about 49% instead: 98% returned on average, or a 2% edge. That's the report's finding; I haven't tested Gamdom myself, and the report says it doesn't prove manipulation.

For 10,000 one-unit bets cashed out at 2x, the expected totals are:
1% edge: 4,950 wins x 2 = 9,900 units returned.
Reported figure: 4,900 wins x 2 = 9,800 returned.
That's about 100 units less returned.

Hundreds or thousands of bets wouldn't reliably settle this. Each bet ends roughly +1 or -1, with standard deviation about 1 unit. The measured edge's standard error is about 1/sqrt(n). Even 40,000 bets gives 0.5 percentage points, so the 1-percentage-point gap between a 1% and 2% edge is only about two standard errors: weak evidence. An individual player's history isn't realistically enough; trackers use millions of rounds, and a published, checkable formula matters.

Reproducible rounds show that results match code, not that the code is fair.

If you play crash at all, it's 18+ only and with money you can afford to lose.

(Drafted with AI assistance, checked before posting.)

[donnajackson75]

Yeah, that's the problem with provably fair. You can verify the result, but that doesn't mean the advertised RTP is correct. Sportbet.one has seed-based verification for its originals too, but without checking the actual payout formula, how would you know the house edge is right?

[5W-KILO]

Do you think they'll eventually quietly patch the crash formula, or just double down and ignore it?

Given how Gamdom team has simply dismissed this entire issue as slander, I don't think they will provide any official or public acknowledgment, nor will they patch formula.
However, it is entirely possible for them to silently tweak h/50 term or crash formula in backend!

I think these casinos never want to compromise their mainstream marketing or brand image.
They just keep ignoring such issue, and once pressure dies down, they quietly fix it.
Until on chain tracker bots begin providing continuous real time proof regarding this, i think they will remain in this defensive mode.

Hahaha, sounds like something that anyone would do, this question is for you, wouldn't you do the same if you are running a online casino? If staying quiet and fixing things later will put your business in a better place, wouldn't you do it?

Atleast they want to maintain their reputation, I would do the same too,  there should be no mistake in this space where too much competition is everywhere, almost every week now new casinos always show up.

The numbers are growing all the time, and one mistake it's over, things will likely not be the same ever again.

[Emitdama]

I expect most casinos do this. It is true that the report clarifies that this does not necessarily mean there is direct manipulation or cheating of the results, but it prevents players from being able to self-verify the integrity of the game before playing.

Misleading promos are not surprising. They are in any industry and even the well-established brands are also committing it. IMO this is still a manipulative tactic. When it comes to verifying, there are different ways of doing it. Like for example here in crypto, we have provably fair system. Then there is said to be a Gamdom verifier which seem not the same to it. There are auditing companies too on here. It was the auditing company called ProvablyFair.org have done verification and found out that Gamdom isn't really provably fair and that their house edge is not really 1% as advertised.

Most casinos claim to be transparent and fair, but this is not the case; in reality, most lack transparency and impose hidden terms that negatively affect the fairness of the games.

Sometimes, those who push and exaggerate that are the ones that are not legit. It is like ''too good to be true'' in other words. We still can verify though like the above, for us to be sure.