Source on GitHub

Smart Contract Address


Source on GitHub

Smart Contract Address


Testing and Issues

You can test this entry and submit issues during the testing period of the Blockchain Contest, Stage 2: Bonus Prize contest.

Entries with serious issues will not be able to win the contest, but even minor issues might be important for overall results.




Grampay Commerce
Promotional webpage:
Video presentation:

Detail smart-contract description:
Smart-contract address: 0:0064D45CE8E80F5A015F09978AA38B9A41493F1B88A9DCB597DE6D36E8200641

Grampay Commerce is a marketplace service for Sellers and Buyers with escrow payments and dispute system.
You can create your own shop in our telegram bot ( and start selling your products!

Demonstrational shops are already done and you are welcome to test them out!
Some screenshots of Telegram bot.
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by rating


Eager Cobra Apr 27, 2020 at 13:45
Opening Section – 5
Concept Explained – 5
Language – 5
Bonus Usability: +0.5

Well-designed website (e-commerce style). Balanced info: opens with an easy-to-understand intro, moves on to more in-depth explanations and further details.

Narration – 5
Visualization – 4
Concept Explained – 5
Bonus: Language +0.25
Bonus: Soundtrack +0.5

Snappy soundtrack, well-matched to easily readable captions. Visualization relies on app/web interfaces, but interface details are not always clearly visible, especially those on mobile (could benefit from using zoom to highlight important parts).

Base Reward: EUR 9,000
Bonus: + EUR 2,000 (working demo shops/bot)

OLD BUGS FIXED: N/A (new contract)

It's possible to override the existing order address and then use a refund to steal money by crafting a hash collision. Ignores the existence of processing fees.

Bug Penalty: EUR 3,000

Total: EUR 8,000
Bold Wolf Apr 27, 2020 at 20:23
I'm glad you liked our project and presentation!
Thanks a lot for your audit: issue was really critical and it should have been fixed. I agree with a fair penalty.
Fast patch was done (, I'll update code and smart-contract ASAP.

Thanks again for this contest! 👍
Nobody added any issues yet...