← Back

Transactions

1234567891011121314ABCDEFGTRANSACTION V1 FORMATDrawing: TX-V1-001Rev: 1.0Date: 03/24/2026Solana MCP SpecificationLEGENDNew Fieldsaddressesmax 2048[[u8; 32]]instruction_headersmax 256instruction_payloadsmax 2048[InstructionPayload]signaturesmax 768[[u8; 64]]version_byte1Blegacy_header3B(u8, u8, u8)transaction_config_mask4Bu32lifetime_specifier32B[u8; 32]num_instructions1Bnum_addresses1B[0] inclusion_fee4Bu32[1] ordering_fee4Bu32[2] compute_unit_limit4Bu32[3] accounts_data_size_limit4Bu32[4] heap_size4Bu32[5] target_proposer4Bu32
OffsetFieldTypeBytes
0version_byteu81
1legacy_header(u8, u8, u8)3
4transaction_config_masku324
8lifetime_specifier[u8; 32]32
40num_instructionsu81
41num_addressesu81
42addresses[[u8; 32]]variable
42config_values (if mask bits set):variable
42 [0] inclusion_feeu324
46 [1] ordering_feeu324
50 [2] compute_unit_limitu324
54 [3] accounts_data_size_limitu324
58 [4] heap_sizeu324
62 [5] target_proposeru324
66instruction_headers[(u8, u8, u16)]variable
66instruction_payloads[InstructionPayload]variable
66signatures[[u8; 64]]variable
Totalup to 66+ bytes

Transaction Limits

ValueMax (SIMD)Prior MaxMax (Format)
transaction size409612324096
signatures per transaction121242
num accounts646496
num instructions6464255
accounts/instruction255255255