SolFit

A gym with a built-in incentive to actually come and train.

Realized on the Solana blockchain.

Best explanation is here

Frontend

Solana program

What is stored on-chain per user?

{
  member_month: 7, // the last month the user paid for, 7 = July 2023
  num_avail: 4 // the number of available rewards for user in this month, range: 0-4, 1 reward = $10
}

What functions does the smart contract have?

• start_membership
  • Simulates the user purchasing the membership for another month
  • Increments member_month
  • Resets num_avail to 4
  • The user must transfer $120 USDC to a PDA
  • Sample transaction
• claim_reward
  • Only valid if num_avail is still > 0
  • In that case, it is decremented and $10 are sent back to the user as cashback
• reset_user
  • For testing purposes
  • Sets member_month and num_avail to 0, essentially cancelling the membership
  • All of the USDC that is stored in the respective PDA is transferred back to them
• Source code of the Solana Program

Deployment

• On mainnet: 7bd3GWaR7h5X6ZAndStp9vD5NbQY5a7V9Q6UMMCm3tCd

Links

• Fun demo video
• Live version
• Slides