@startuml
'https://plantuml.com/sequence-diagram

autonumber

Client -> Web3: bc connect
Web3 --> Client: return chainId->net_id, account
Client -> Server: getNonce{account,net_id}
Server --> Client: return Nonce{nonce}

Client -> Server: auth{account, nonce, signature, tips}
Server --> Client: return {token}

Client -> Server: sellMyNft{account, token, nft_token, s_price, payment_token_address, nonce, signature, net_id}
Server --> Client: return ok

Client -> Server: buyNft{account, token, nft_token, payment_token_address, nonce, signature, net_id}
Server --> Client: return ok

@enduml