VEP 8: AccountBlock Data Content Type Definition


In general, the data field in account block can be used to carry any info when sending transactions through tx_sendRawTx API. In order to utilize or display the carried data correctly, it is necessary to describe the data content type in uniform way.


The proposal suggests to append 2 bytes content type at beginning to indicate what type of data is followed.

Content type is a uint16 number stored in big endian format. Please note that types 1(0x0001) - 2048(0x0800) are officially reserved and should not be used by third party.


It is known that content type might not be correctly recognized under the situation calling a smart contract, due to occasional conflict with method hash, which occupies the first few bytes of data field.

Defined Type

General Type

Type Type(Hex) Description
Binary 0x0001 Reserved, not used yet
UTF-8 String 0x0002 Transaction comment

Custom Type

Type Type(Hex) Description
Grin Wallet Data 0x8001 Carrying Grin transaction index