Summary
DA Builder combines offchain transaction aggregation with onchain EIP-7702 proposer execution so multiple participants can share Ethereum execution overhead.System Architecture
Component Responsibilities
User EOA With EIP-7702 Proposer Code
The user EOA contains delegated EIP-7702 account code. The proposer code can be Spire’sTrustedProposer or a TrustlessProposer implementation.
TrustedProposer is best for dedicated EOAs where trusting Spire’s DA Builder service is acceptable. TrustlessProposer is best for applications that require account-owner authorization for each delegated call.
DA Builder Service
The DA Builder service accepts transaction submissions, validates account setup and GasTank funding, groups compatible transactions, returns transaction hashes, and manages status tracking. DA Builder is not a full Ethereum RPC provider. Use a standard RPC provider for reads, archive queries, event logs, and direct fallback.ProposerMulticall Contract
ProposerMulticall executes aggregated onchain transactions. It calls each participant’s proposer account code in sequence so multiple user operations can share duplicated execution overhead.
GasTank Contract
GasTank stores user deposits and provides the accounting source for DA Builder transaction costs.dab_accountInfo returns GasTank balance and outstanding_charge for an account.
Data Flow
- The user deposits ETH into GasTank.
- The user delegates a dedicated EOA to
TrustedProposerorTrustlessProposer. - The application sends a signed transaction to the DA Builder RPC endpoint.
- DA Builder validates the account, funding, and transaction.
- DA Builder aggregates compatible transactions.
ProposerMulticallexecutes proposer calls onchain.- DA Builder calculates costs and updates GasTank charges.
- The application polls
eth_getTransactionReceiptordab_transactionStatus.
Trust Boundaries
| Boundary | TrustedProposer | TrustlessProposer |
|---|---|---|
| Delegated execution | Spire’s DA Builder service can execute through the delegated EOA | Proposer code verifies account-owner authorization before execution using ecrecover |
| Application signing changes | Not required after delegation | Required for EIP-712 proposer payloads |
| Best account type | Dedicated hot-wallet EOA with limited permissions | EOA that needs explicit authorization for delegated calls |
| Main risk | Overbroad delegated authority | Incorrect signing, nonce, deadline, or storage-layout implementation |
Failure Modes
| Failure mode | Effect | Handling |
|---|---|---|
| GasTank not funded | Submission will be unable to aggregate | Deposit ETH and poll dab_accountInfo |
| DA Builder unavailable | DA Builder submission path fails | Submit directly through standard RPC |
| Unsupported RPC method | Request fails or is not appropriate for DA Builder | Use a standard Ethereum RPC provider |
| Bad TrustlessProposer payload | Delegated call reverts | Validate EIP-712 signing, nonce, deadline, and gas limit |
Unsupported Uses
Do not use DA Builder as an archive node, indexer, read-heavy RPC provider, general-purpose wallet backend, or blob compression system. DA Builder’s architecture is for transaction aggregation and GasTank-based cost accounting.Internal Links
- Full Integration Guide - Choose proposer path.
- Monitor Account - Monitor GasTank and status.
- Quick Reference - Endpoints and methods.
- Compare Alternatives - Decide whether DA Builder fits.