Transaction relaying services allow Safe users to submit and execute transactions without holding the native gas token on the target chain. In the Safe ecosystem, relayers such as Gelato and Pimlico accept signed Safe transactions off-chain, wrap them in their own execution calls, and submit them on-chain, paying gas from a relayer-controlled balance. This pattern is foundational for gasless UX, DAO treasury operations where signers should not need ETH, and automated execution of recurring Safe transactions. However, it shifts the trust boundary: the relayer becomes a mandatory intermediary between the Safe's signers and on-chain execution.
Protocols
Transaction Relaying Services and Trust Assumptions
A technical analysis of how relayers enable gasless execution for Safe smart accounts, the trust and liveness trade-offs of different relayer models, and operational strategies for managing relayer dependencies.
introduction
RELAYER DEPENDENCIES AND TRUST MODELS
Introduction
How transaction relaying services abstract gas costs from Safe users while introducing operational dependencies and trust assumptions that teams must model before adoption.
The operational risk surface depends on the relayer architecture. Centralized relayers introduce liveness risk—if the relayer service is down, transactions stall regardless of how many signers have confirmed. Decentralized relay networks distribute execution across multiple operators but introduce fee-market dynamics and potential race conditions. In both models, the relayer can technically censor transactions by refusing to submit them, though it cannot forge signatures or alter the transaction payload if the Safe's threshold and signature checks are correctly configured. Teams must also assess whether the relayer has the ability to front-run or reorder transactions in ways that could affect protocol outcomes.
For Safe deployments that depend on relayers for critical treasury operations, DAO votes, or automated liquidation protection, Chainscore Labs can evaluate the relayer architecture against the team's security and liveness requirements. This includes reviewing fallback mechanisms when the primary relayer fails, assessing the trust assumptions of gasless transaction flows, and recommending monitoring and alerting patterns that detect relayer censorship or downtime before it causes operational impact.
TRANSACTION RELAYING TRUST MODEL
Quick Facts
Operational dependencies and trust assumptions for teams relying on third-party relayers to submit Safe transactions
| Area | What changes | Who is affected | Action |
|---|---|---|---|
Relayer role | Relayers submit signed transactions on behalf of Safe owners, paying gas and managing nonce ordering | DAO operators, institutional custodians, wallet integrators | Map which relayers your Safes depend on and whether they are the sole submission path |
Gasless execution | Users sign off-chain; relayer wraps the signature into execTransaction and pays gas, often recovering costs via refundReceiver | Treasury teams, DeFi protocols, end-user wallets | Verify that gas refund logic is correctly configured and that the relayer cannot drain gas tokens |
Censorship risk | A centralized relayer can delay or refuse to submit a valid signed transaction | Governance multisigs, time-sensitive operations, liquidation-sensitive positions | Maintain an alternative submission path via direct RPC call or a second relayer network |
Liveness dependency | If the relayer service is down, transactions cannot be submitted through that channel | All Safe users relying exclusively on relayed submission | Test fallback to Safe SDK, CLI, or direct contract interaction at least quarterly |
Transaction ordering | Relayer controls submission order for transactions it sponsors; can reorder within nonce constraints | High-frequency Safe operators, algorithmic treasury strategies | Audit relayer mempool behavior and confirm that nonce sequencing matches your operational requirements |
Signature collection | Off-chain signatures are often collected via Safe Transaction Service before relayer submission | Custodians, MPC wallet providers, multi-signer DAOs | Verify that the Transaction Service API is not the sole signature collection path; test direct packed signature assembly |
Relayer failure mode | A relayer that accepts signatures but fails to submit on-chain can cause transactions to appear 'signed' but never execute | Operations teams, support engineers | Monitor for transactions stuck in 'awaiting execution' state and set alerting thresholds for relayer submission latency |
technical-context
GASLESS EXECUTION AND TRUST MODELS
How Relaying Works in the Safe Ecosystem
Analyzes the operational role of relayers in the Safe ecosystem, covering gasless transaction flows, trust assumptions of different relayer models, and fallback mechanisms.
Safe smart accounts require a native gas token balance on the execution chain to process transactions, creating a friction point for newly deployed Safes or organizations that prefer to pay fees in a different asset. Transaction relaying services solve this by decoupling the transaction signer from the gas payer. In the Safe ecosystem, relayers like Gelato and Pimlico accept a signed Safe transaction off-chain, wrap it in a relay call, and submit it on-chain using their own gas funds, collecting a fee or refund from the Safe or a third-party paymaster. This allows DAOs to sponsor user transactions, treasury operations to execute without pre-funding gas tokens, and wallet interfaces to offer gasless flows to end users.
The trust model varies significantly by relayer architecture. A centralized relayer operated by a single entity introduces liveness risk: if the relayer service is down, transactions stall. A decentralized relayer network like Gelato distributes execution across multiple executors, reducing single points of failure but introducing new trust assumptions around executor selection and fee markets. In all models, the relayer can technically censor transactions by refusing to relay them, though it cannot alter the transaction's payload without invalidating the signatures. Teams must assess whether their relayer can front-run, whether the relayer's fee model creates adverse incentives, and whether the relayer has visibility into sensitive transaction data before execution.
Safe's architecture provides fallback mechanisms when relayers are unavailable. Any Safe signer with the native gas token can always submit a fully signed transaction directly to the Safe contract via execTransaction, bypassing the relayer entirely. The Safe Transaction Service API and SDKs support this direct execution path. For teams building high-reliability operations, Chainscore Labs can evaluate relayer architecture, design multi-relayer fallback strategies, and review the integration between Safe's off-chain signature collection and the chosen relayer's submission API to ensure transactions can always reach the chain.
RELAYER DEPENDENCY ANALYSIS
Affected Actors
Treasury and Governance Teams
DAO operators using gasless transactions or sponsored execution are directly exposed to relayer availability risk. If a relayer network stalls or censors transactions, time-sensitive governance votes, payroll disbursements, and emergency pauses may fail silently.
Action items:
- Map every Safe that depends on a third-party relayer for execution.
- Maintain a fallback execution path using a self-hosted relayer or direct gas payment from a funded EOA signer.
- Test fallback execution on a quarterly basis, including during high-congestion periods.
- Monitor relayer-specific transaction status endpoints and set alerts for abnormal latency or failure-rate spikes.
Chainscore can design relayer fallback procedures and review your treasury execution architecture for single points of failure.
implementation-impact
TRUST ASSUMPTIONS AND OPERATIONAL RISKS
Relayer Model Comparison
A technical comparison of relayer architectures used with Safe, analyzing the distinct trust, liveness, and censorship-resistance properties of each model.
01
Trusted Relay Service (e.g., Gelato 1Balance)
A centralized or semi-centralized service that executes transactions on behalf of a Safe. The relayer holds a gas balance and pays for execution, often abstracting gas from the end-user. The primary trust assumption is that the relayer will not censor transactions and will remain live. A compromised or insolvent relayer can halt operations for dependent Safes. Teams must monitor the relayer's balance, API health, and governance. Chainscore can audit a Safe's fallback mechanisms to ensure operations can bypass a failed relayer.
02
ERC-4337 Bundler and Paymaster
In this model, a Safe uses the Safe4337Module to package transactions as UserOperations. A third-party paymaster sponsors gas, and a bundler submits the operation to an entry point contract. Trust is distributed: the bundler is responsible for inclusion, while the paymaster controls gas sponsorship policy. Censorship risk is shared between these actors. A paymaster can block a specific Safe by refusing to sponsor its UserOperations. Chainscore can review paymaster logic and bundler selection criteria to identify single points of failure.
03
Self-Funded Relayer (Custom Infrastructure)
A relayer operated by the Safe's own organization, typically using a hot wallet funded with the chain's native token. This model eliminates external liveness and censorship risks but introduces the operational burden of managing key material, monitoring balances, and handling nonce conflicts. The trust assumption shifts entirely to the internal infrastructure's security and reliability. A compromised relayer key can drain its gas bank. Chainscore can design secure key management and monitoring architectures for self-hosted relayers.
04
Competitive Relayer Network
A permissionless network where multiple relayers compete to execute a transaction for a fee, similar to a mempool model. This architecture minimizes censorship risk, as any relayer can pick up a signed transaction. The primary challenge is ensuring fair fee discovery and preventing front-running. For Safe transactions, the sequential nonce model adds complexity, as a stuck transaction blocks all subsequent ones regardless of the relayer. Chainscore can model nonce-queue dynamics in competitive relayer environments to prevent deadlocks.
05
Conditional Execution and Automation (e.g., Gelato Tasks)
A relayer that executes a Safe transaction only when predefined on-chain conditions are met, such as a price threshold or a time interval. This model introduces a resolver component that monitors state and triggers execution. The trust assumption extends to the resolver's accuracy and liveness. A faulty resolver can cause missed or incorrect executions, potentially leading to financial loss in time-sensitive operations like liquidation protection. Chainscore can verify resolver logic and design circuit breakers for automated Safe operations.
TRUST ASSUMPTIONS AND FAILURE MODES FOR SAFE TRANSACTION RELAYING
Risk Matrix for Relayer Dependencies
Evaluates the operational risks introduced by relying on third-party or custom transaction relayers for Safe transaction execution, including gasless flows, censorship vectors, and fallback readiness.
| Risk | Failure mode | Severity | Mitigation |
|---|---|---|---|
Relayer Liveness | The relayer becomes unresponsive or halts operations, preventing the submission of fully signed transactions to the mempool. | High | Implement a fallback relayer or direct submission path via SDK/CLI. Monitor relayer health endpoints and maintain a funded EOA for emergency self-relaying. |
Transaction Censorship | The relayer selectively filters or delays transactions based on the Safe address, target contract, or payload data. | High | Use multiple relayer providers with diverse operational policies. Verify transaction inclusion through independent mempool monitoring. Maintain capability to broadcast raw signed transactions directly. |
Gas Accounting Opacity | The relayer's gas estimation, pricing, or refund mechanism is opaque, leading to unexpected costs, stuck transactions, or GS000 revert errors. | Medium | Audit the relayer's gas buffer logic and fee model. Simulate transactions locally with |
Signature Data Leakage | The relayer logs or mishandles the collected off-chain signatures, exposing the Safe's signing activity or enabling signature replay analysis. | Medium | Ensure the relayer uses encrypted transport and does not persist raw signatures longer than necessary. Prefer relayers with a published data handling policy. Use EIP-712 typed data to bind signatures to a specific chain and contract. |
Paymaster Dependency | In gasless flows, the ERC-4337 paymaster sponsoring the UserOperation becomes insolvent, changes policy, or is paused, causing transaction rejection. | High | Verify the paymaster's deposit balance and staking status on the EntryPoint. Configure a user-staked paymaster or fallback gas payment method. Monitor paymaster-related events for policy changes. |
Relayer Front-Risk | A malicious or compromised relayer reorders, inserts, or front-runs transactions from the same Safe or related Safes. | Medium | Use a relayer with a strong reputation and no conflicting business lines. For high-value transactions, use a private mempool or direct submission to a trusted builder. Review the relayer's transaction ordering policy. |
API and Indexer Inconsistency | The relayer's view of the Safe state (nonce, threshold, pending transactions) is stale due to indexer lag, causing transaction submission with an incorrect nonce. | Medium | Query the Safe contract state directly from a full node for critical pre-flight checks. Do not rely solely on the relayer's API for the current nonce. Implement client-side nonce validation before signing. |
TRANSACTION RELAYING SERVICES AND TRUST ASSUMPTIONS
Operator Resilience Checklist
A practical checklist for teams operating Safes that depend on third-party or custom transaction relayers. Use this to verify that your relayer architecture is resilient to censorship, failure, and misconfiguration, and that fallback procedures are tested and ready.
Identify every relayer service your organization uses, including Gelato, Pimlico, custom relayers, or bundler-based relayers for ERC-4337 operations. For each dependency, document:
- Which Safes or modules rely on it
- What transaction types it handles (execution, gasless sponsorship, UserOperation submission)
- The trust model: does the relayer hold signing authority, or does it only submit pre-signed payloads?
- The chain(s) it operates on
Why it matters: A single relayer outage can block all dependent Safes. Without a complete inventory, you cannot assess blast radius or plan fallbacks.
Readiness signal: A maintained registry of relayer dependencies, reviewed at least quarterly.
resource-links
SAFE RELAYER REFERENCES
Source Resources
Canonical and operator-facing resources for evaluating Safe transaction relaying, sponsored execution, bundler dependencies, and fallback paths when managed relayers are unavailable.
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RELAYER TRUST AND OPERATIONS
Frequently Asked Questions
Common operational and architectural questions about transaction relaying in the Safe ecosystem, covering trust models, failure modes, and resilience strategies.
A relayer is an off-chain service that submits a fully signed Safe transaction on-chain, paying the gas fee in the native token so the Safe's signers do not need to hold it. The flow works as follows:
- Signers produce the required off-chain EIP-712 signatures for a standard
execTransactioncall. - The signed payload and signatures are sent to the relayer's API instead of being broadcast directly.
- The relayer wraps the
execTransactioncall in its own transaction, funds it with gas, and submits it to the mempool. - The Safe executes the transaction. The relayer is reimbursed if the transaction includes a gas payment mechanism, or it absorbs the cost as a subsidized service.
This pattern is critical for DAOs and institutional users who want signers to operate without managing ETH or other gas tokens on every chain. It also enables sponsored transactions where a third party covers execution costs.
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