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This section explains the anatomy of a transaction in the NEAR Protocol, describing its structure, components, and the actions that can be performed within a transaction. A transaction is a request from a user to the network to perform a set of actions. To create a transaction, the user must specify the following fields:
  • Signer: the account that signs the transaction
  • Actions: the set of actions to be performed (see below)
  • Receiver: the account on which to perform the actions
In addition, a transaction has the following fields to ensure its integrity and validity:
  • PublicKey: the public key used to sign the transaction (so the network can verify the signature)
  • Nonce: a number that is incremented for each transaction sent by the Signer
  • BlockHash: the hash of a recent block, to limit the time-validity of the transaction
Users create transactions and sign them with their private keys. Then, the transaction and its signature are broadcast together to the network, where they are validated and processed.
Each transaction has exactly one Signer and Receiver, but can have multiple Actions.
About nonce values
  • When adding a key, the nonce is automatically assigned - particularly, it is given the value block height * 10^6 - so the value in the ADD_KEY action is ignored
  • A transaction is accepted only if the nonce value is in the range of:
    • [(current_nonce_of_access_key + 1) .. (block_height * 10^6)]
  • Once a transaction is accepted, the access key’s nonce is set to the nonce value of the included transaction
  • A transaction signed with a gas key additionally specifies a nonce_index selecting one of the key’s parallel nonce lanes; the same rules then apply to that lane’s nonce independently

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Transaction limits

A signed transaction must fit within both of these limits: The size limit includes the entire signed transaction: account IDs, public key, nonce, block hash, actions (including function-call arguments or contract code), and signature. The space available for your payload is therefore smaller than 1.5 MiB. Nodes reject larger transactions with TransactionSizeExceeded. The size and gas limits are separate: attaching more gas does not let you upload more bytes. To upload larger data, split it across transactions if your contract supports incremental uploads. These limits are configured by max_transaction_size and max_total_prepaid_gas in the protocol configuration.

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Actions

Each transaction can have one or multiple Actions, which are the actual operations to be performed on the Receiver account. There are different types of actions that can be performed:
  1. FunctionCall: to invoke a function on a contract (optionally attaching NEAR to the call)
  2. Transfer: to transfer tokens to another account
  3. DeployContract: to deploy a contract in the account
  4. DeployGlobalContract: registers a global contract referenced by its contract hash or by its account ID
  5. UseGlobalContract: uses a registered global contract by contract hash or account ID
  6. CreateAccount: to create a new sub-account (e.g. ana.near can create sub.ana.near)
  7. DeleteAccount: to delete the account (transferring the remaining balance to a beneficiary)
  8. AddKey: to add a new key to the account (either FullAccess or FunctionCall access, optionally as a gas key)
  9. DeleteKey: to delete an existing key from the account
  10. TransferToGasKey: to fund a gas key’s prepaid gas balance with NEAR
  11. WithdrawFromGasKey: to move NEAR from a gas key’s balance back to the account
  12. DelegateActions: to create a meta-transaction (Delegate). DelegateV2, which lets a gas key sign the delegate action, is rejected from protocol version 87
  13. Stake: special action to express interest in becoming a network validator (its own public_key field — the validator’s block-production key — must stay ed25519, regardless of what key signed the transaction)
  14. DeterministicStateInit: special action to create a deterministic account (an advanced kind of implicit account)
  15. UniversalStateInit: special action to create a universal account, installing its code, storage, and access keys in one step
For example, bob.near can bundle the following actions in a single transaction:
  • Create the account contract.bob.near
  • Transfer 5 NEAR to contract.bob.near
  • Deploy a contract in contract.bob.near
  • Call the function init in contract.bob.near
The Actions are executed in the order they are specified in the transaction. If any of the actions fails, the transaction is discarded and none of the actions take effect.
One ReceiverNotice that all actions are performed on the same account. It is not possible to perform actions on multiple accounts in a single transaction, because transactions can have only one receiver