Gatekeeper
DeFi transaction decoding and whitelist evaluation service for blockchain applications.

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Overview
Gatekeeper decodes transactions and evaluates them against protocol-specific whitelist rules.
Key capabilities:- Decode transactions - Converts raw calldata into structured, human-readable intents
- Evaluate Whitelist Rules - Validates transactions against protocol-specific whitelist policies
- Nested transaction support - Handles multicall and batched operations with full context
- Flexible deployment model - Deploy in any environment or run as a sidecar

Background
Gatekeeper is originally designed for Custodians and Institutional Wallets to enable DeFi access. It accepts transactions crafted by an untrusted 3rd party (e.g a DApp frontend), decodes the transaction back to a trusted intent, and validates it matches the expected, approved behavior.
This acts as an integration point to scalably integrate DeFi services into existing transaction policy & signing workflows.
While designed for wallet providers, it's also useful to anyone who needs to ensure only specific transactions are processed for signing and prevent blind-signing style attacks.
Challenges with DeFi Transactions
DeFi transactions come with unique challenges.
- Crafted in untrusted environments (Dapps, 3rd party APIs, or unhardened 1st party services relying on realtime blockchain data)
- Move funds, not always in the most obvious way (not a basic transfer)
- Utilize multicalls, nested transactions, batched transactions, token allowances
- Compose across multiple protocols
- Each protocol is unique
Common attacks manipulate nested parameters, easily bypassing address-based allowlists.
Solving this requires ongoing per-protocol development efforts and testing/QA.By decoupling the DeFi decoding & whitelisting, you gain benefits such as:
- Per-protocol efforts encapsulated into declarative configuration, not custom code.
- One-time integration point to translate DeFi into existing systems.
- Thoroughly-tested, rarely-changing evaluation logic
- Limited scope of incremental testing & QA on new protocols.
Can it be trusted?
Gatekeeper is a stateless service that can be deployed in any environment in a zero-trust configuration.
See Security for more details.

