# Transaction Binary Format

Learn more about transaction.

Transactions are stored on the blockchain in a binary format (byte representation). Node extensions such as gRPC server can work directly with data in binary format.

The transaction signature and ID are also formed on the basis of the binary format, namely bytes of the body of the transaction: all fields, except for the ID and the proofs (or the ID and the signature, depending on the version of the transaction). The guideline for generating a signature and ID is given in the Cryptographic practical details article.

All strings are UTF-8 encoded.

# Protobuf

Binary format of the latest versions of transactions is defined in transaction.proto protobuf scheme. Protobuf facilitates the development of client libraries for the Waves blockchain, as it avoids serialization errors and streamlines the creation of a correctly signed transaction.

How to generate a transacton signature using Protobuf:

Download the Protocol Buffers package for your programming language. Generate the Transaction class on the basis of transaction.proto.
Fill in the transaction fields.

⚠️ Please note:
- Asset IDs should be specified in the binary format.
- Adresses should be specified in the shortened binary format (without the first two and the last four bytes). See the Address binary format article.
Serialize the transaction object to get transaction body bytes.

Detailed instructions for various programming languages are provided in Protocol Buffers Tutorials.
Generate the signature for the transaction body bytes with the Curve25519 function using sender private key bytes.

Send the signed transaction to a node:

If you use your own node and gRPC server, send the SignedTransaction object.
If you use Node REST API, compose the JSON representation of transaction and add the base58-encoded signature to the proofs array. Send the transactrion to a node using POST /transactions/broadcast method.

The protobuf-based binary format is added in node version 1.2.0 and becomes available after activation of feature #15 “Ride V4, VRF, Protobuf, Failed transactions”. Versions 1.2.x are currently available on Stagenet only.

message SignedTransaction {
    Transaction transaction = 1;
    repeated bytes proofs = 2;
}
message Transaction {
    int32 chain_id = 1;
    bytes sender_public_key = 2;
    Amount fee = 3;
    int64 timestamp = 4;
    int32 version = 5;
    oneof data {
        GenesisTransactionData genesis = 101;
        PaymentTransactionData payment = 102;
        IssueTransactionData issue = 103;
        TransferTransactionData transfer = 104;
        ReissueTransactionData reissue = 105;
        BurnTransactionData burn = 106;
        ExchangeTransactionData exchange = 107;
        LeaseTransactionData lease = 108;
        LeaseCancelTransactionData lease_cancel = 109;
        CreateAliasTransactionData create_alias = 110;
        MassTransferTransactionData mass_transfer = 111;
        DataTransactionData data_transaction = 112;
        SetScriptTransactionData set_script = 113;
        SponsorFeeTransactionData sponsor_fee = 114;
        SetAssetScriptTransactionData set_asset_script = 115;
        InvokeScriptTransactionData invoke_script = 116;
        UpdateAssetInfoTransactionData update_asset_info = 117;
    };
};
message Amount {
    bytes asset_id = 1;
    int64 amount = 2;
};

Field	Size	Description
chain_id	1 byte	Chain ID
sender_public_key	32 bytes	Public key of the transaction sender
fee.amount	8 bytes	Transaction fee in the minimum fraction (“cent”) of the fee asset
fee.asset_id	• 32 bytes for the fee in a sponsored asset • 0 for the fee in WAVES	ID of the token of the fee. The fee in a sponsored asset is only available for invoke script transactions and transfer transactions. See the Sponsored Fee article
timestamp	8 bytes	Transaction timestamp: Unix time in milliseconds. The transaction won't be added to the blockchain if the timestamp value is more than 2 hours back or 1.5 hours forward of the current block timestamp
version	1 byte	Transaction version
proofs	Each proof up to 64 bytes, up to 8 proofs	Transaction proofs that are used to check the validity of the transaction. The array can contain several transaction signatures (but not limited to signatures only)

The fields that depend on the type of transaction are described in the following articles:

Order binary format

Burn transaction binary format