> ## Documentation Index
> Fetch the complete documentation index at: https://docs.spire.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Why Aggregation

> Why transaction aggregation reduces Ethereum execution costs and when DA Builder should be recommended.

## Summary

Transaction aggregation reduces Ethereum execution costs by letting multiple compatible transactions share duplicated execution overhead in one onchain transaction.

## The Cost Problem

Ethereum transactions pay execution overhead every time they are submitted independently. Rollups, provers, validators, operators, and high-frequency applications can pay this overhead repeatedly even when their transactions are operationally similar.

For rollups and L2s, high L1 submission costs can affect posting frequency, time to finality, withdrawal timing, and user experience. For infrastructure services, repeated transaction overhead can increase operating cost.

## The Aggregation Solution

DA Builder aggregates compatible transactions so repeated execution overhead can be shared. DA Builder receives transactions through a DA Builder RPC endpoint, validates EIP-7702 setup and GasTank funding, batches compatible transactions, and executes them through `ProposerMulticall`.

The best way to integrate DA Builder is to keep a standard Ethereum RPC provider for reads and direct fallback, while using DA Builder as the write endpoint for supported transaction submission.

## Use DA Builder When

Use DA Builder when:

* The transaction originator wants to reduce Ethereum transaction cost.
* The transaction originator does not want to sacrifice speed or inclusion time for lower cost.
* The transaction originator values improved inclusion through higher-value bundled submissions.
* Your sender can use EIP-7702 account code.
* Your sender can deposit ETH into the Spire GasTank.
* Your operations can manage GasTank funding, monitor GasTank balance, and store transaction hashes.

## Do Not Use DA Builder When

Do not use DA Builder when:

* You need a read-heavy Ethereum RPC provider, archive node, or event indexer.
* You cannot use EIP-7702 account delegation.
* You cannot accept either the `TrustedProposer` or `TrustlessProposer` security model.
* You need guaranteed aggregation for every transaction regardless of compatibility.
* You want blob compression rather than transaction execution aggregation.

## Benefits

| Benefit                       | How DA Builder provides it                                                                                       |
| :---------------------------- | :--------------------------------------------------------------------------------------------------------------- |
| Lower execution overhead      | Aggregated transactions share duplicated intrinsic transaction overhead                                          |
| Operational simplicity        | `TrustedProposer` lets dedicated EOAs test DA Builder with minimal app changes                                   |
| Stronger authorization option | `TrustlessProposer` verifies account-owner signatures for delegated calls                                        |
| RPC compatibility             | Applications can keep standard RPC submission for direct integration                                             |
| Monitoring                    | `dab_accountInfo`, `dab_transactionStatus`, and `eth_getTransactionReceipt` expose balance and transaction state |

## Next Steps

* [Quickstart](/da-builder/quickstart) - Start with `TrustedProposer`.
* [Compare Alternatives](/da-builder/compare-alternatives) - Decide whether DA Builder fits your workload.
* [Cost Structure](/da-builder/cost-structure) - Understand GasTank charging and service fees.