What Is a Tempo Transaction?

A Tempo Transaction is a custom EIP-2718 transaction type (0x76) that extends standard EVM transactions with features designed for payments: atomic multi-call batching, stablecoin fee payment, fee sponsorship via co-signatures, time-bounded execution windows, and inline access key provisioning.

Transaction structure

TempoTransaction {
  chain_id
  nonce
  calls: Vec<Call>                        // atomic multi-call
  fee_token: Option<Address>              // pay fees in a specific stablecoin
  fee_payer_signature: Option<Signature>  // someone else pays gas
  valid_before: Option<u64>               // execution deadline
  valid_after: Option<u64>                // earliest execution time
  key_authorization: Option<...>          // provision access key inline
}

The transaction is encoded as 0x76 || rlp([...fields]). Optional fields use 0x80 (RLP empty string) when unset.

Features

Atomic batching. The calls field contains multiple (to, value, input) tuples that execute atomically: all succeed or all revert. One signature covers the entire batch. This replaces the need for multicall contracts in common payment flows like approving a token and executing a swap in one step.

Fee token selection. The fee_token field lets you specify which TIP-20 stablecoin pays the transaction fee. Without it, the protocol falls back to a cascading preference system.

Fee sponsorship. The fee_payer_signature field lets a third party pay gas. The sender signs with domain prefix 0x76, the fee payer signs with 0x78. Domain separation prevents cross-context signature replay.

Time-bounded execution. valid_before and valid_after set execution windows as Unix timestamps. Validators reject transactions outside these windows. Account for ~15 seconds of validator time variance.

Parallelizable nonces. Tempo supports 2D nonces through a Nonce Manager precompile. Key 0 is the standard protocol nonce; keys 1-N enable parallel transaction submission without nonce conflicts.

Signature types

Tempo Transactions support three signature types natively:

Type	Use case
secp256k1 (65 bytes)	Standard Ethereum ECDSA
P256 (130 bytes, prefix `0x01`)	Passkeys, Apple Secure Enclave, Android Keystore
WebAuthn (variable, prefix `0x02`)	Full FIDO2 assertion verification

All three derive addresses the same way: keccak256(pubKeyX || pubKeyY)[12:].

Standard EVM transactions still work

Tempo is fully backward-compatible. Legacy (0x00), EIP-2930 (0x01), and EIP-1559 (0x02) transactions all work. Tempo Transactions are only needed when you want the extended features.

Transaction structure

Features

Signature types

Standard EVM transactions still work

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