Smart contract wallets like Safe unlock powerful workflows that go far beyond simple token transfers. One of the most important and often under‑utilized tools is the Safe Transaction Builder.
This guide walks through what the Transaction Builder is, why it matters, and how to use it step by step, with practical examples and best practices, so you can confidently craft and execute complex on‑chain operations in a single transaction.
What Is the Safe Transaction Builder?
The Transaction Builder is a Safe application designed to make it easier to create, review, and execute batched transactions.
Instead of manually sending multiple transactions one by one, the builder lets you:
- Visually construct a sequence of transactions
- Edit and review each action before execution
- Bundle multiple actions into one atomic transaction
- Execute everything with a single confirmation flow
These batches can include any transaction type, from basic token transfers to advanced smart contract calls.
A common example is combining actions that usually require multiple steps such as Approve → Swap on a DEX into one Safe transaction.
Why Batched Transactions Matter
One of the key advantages of using a smart contract wallet like Safe is its ability to execute batched transactions.
Without batching:
- Each transaction must be signed and executed separately
- More confirmations required
- Higher operational friction
- Higher total gas usage
With batching:
- Multiple actions are bundled together
- Only one execution is required
- All actions succeed or fail together (atomicity)
- Cleaner operational flows for teams and DAOs
Safe enables this through the MultiSend library, which allows multiple contract calls to be wrapped into a single on‑chain transaction.
Where to Find the Transaction Builder
- Open your Safe
- Navigate to New Transaction
- Select Transaction Builder
This opens the interface where you can begin constructing your transaction batch.
Step‑by‑Step: Building a Transaction Batch
Step 1: Choose the Contract You Want to Interact With
In the Transaction Builder, you start by defining the smart contract you want to call:
- Enter the contract address
- Select the network (if applicable)
If the contract is verified on Sourcify, Safe will automatically fetch the ABI for you.
If the ABI is not fetched automatically, you can manually paste it into the "Enter ABI" field. Common sources include:
- Sourcify
- Etherscan / block explorer
- Project repositories
The ABI defines what functions you can call and how the data is encoded.
Step 2: Select the Function and Configure Parameters
Once the ABI is loaded:
- Choose the function you want to call
- Fill in the required parameters
- Set any ETH value if needed
At this stage, you are effectively crafting a raw smart contract call, but with a guided UI instead of manual calldata encoding.
Step 3: Add the Transaction to the Batch
After configuring the function call, click Add transaction.
- The transaction is added to the list on the right‑hand side
- You can now see all prepared actions in order
This is where the real power comes in: you can continue adding transactions to build a long, ordered batch.
Example: Updating Safe Owners and Threshold in One Transaction
A practical example of batching is Safe configuration changes.
Instead of executing multiple governance actions separately, you can:
- Remove an existing owner
- Add a new owner
- Update the signing threshold
All within one single transaction. This ensures no intermediate unsafe states, cleaner governance changes, and one execution instead of many.
Managing Your Transaction List
The Transaction Builder provides several tools to manage your batch:
- Reorder transactions if execution order matters
- Remove or edit individual transactions
- Clear the entire list
- Bookmark the transaction batch for later use
- Download the batch as a JSON file
These features make it easy to iterate safely before execution.
Sharing and Reusing Transaction Batches
One of the most powerful (and underrated) features is the ability to export transaction batches as JSON.
This allows you to:
- Prepare transactions ahead of time
- Share them with another Safe owner or operator
- Have a different party import and execute them
This is especially useful for DAO operations, multi‑team coordination, and audited or pre‑approved transaction flows. The receiving user can simply import the JSON file into their Transaction Builder and execute it.
Review and Execute
Before execution:
- Carefully review each transaction in the batch
- Verify addresses, parameters, and values
- Confirm execution order
Once submitted, the batch follows the normal Safe confirmation process — but executes as one atomic transaction on‑chain.
Important Security Considerations
The Transaction Builder is extremely powerful. It allows you to interact with any smart contract at the blockchain level, including crafting raw calldata. This flexibility also introduces risk.
Best practices:
- Only interact with contracts you fully understand
- Double‑check all parameters
- Never blindly import JSON from untrusted sources
- Test complex flows on a testnet first
If used correctly, the Transaction Builder becomes one of the most valuable tools in the Safe ecosystem.
Palmera
Palmera is a multisig infrastructure provider for EVM chains, specializing in the deployment and operation of smart account infrastructure compatible with Safe across L1s, L2s, and L3s.