Shield Docs — Updated

Zero-trust transaction validation for Yield.xyz integrations.

Overview

When interacting with on-chain yield protocols through the Yield API, transaction integrity is critical. Even a small modification to an unsigned transaction can redirect funds to an attacker's address, trigger unintended contract calls, or drain token approvals.

Shield is a validation layer that lets you verify every unsigned transaction returned by the Yield API before presenting it for signing. It decodes each transaction into a typed structure — ABI decoding for EVM, instruction parsing for Solana, and TronWeb decoding for Tron — validates each decoded field against a verified template for the specified yield integration, and re-encodes EVM calldata to detect any byte-level tampering. If anything deviates from the expected pattern, Shield flags it immediately.

Shield ships as both a TypeScript library and standalone binaries, so you can embed it directly into your integration regardless of tech stack.

GitHub repository

</aside>

NPM Package

</aside>

Key features

Zero-trust verification — Every transaction must match a pre-audited pattern. Shield trusts nothing by default.
Multi-chain support — Works across EVM (14 networks), Solana, and Tron, with Cosmos and additional L2s coming soon.
1,486 vault coverage — Generic ERC-4626 validator covers 98% of all ERC-4626 yields the API supports, plus dedicated validators for Lido and Rocket Pool.
Standalone binaries — Pre-built for Linux, macOS (ARM + Intel), and Windows. No Node.js required.
Language-agnostic — JSON protocol over stdin/stdout with integration guides for Go, Python, and Rust.
Tamper detection — Byte-for-byte calldata re-encoding catches any modification to EVM transactions, including appended or corrupted data.
Clear error reporting — Immediate, structured feedback on exactly why a transaction failed validation.

Modes

Shield supports two operating modes. Your choice depends on where you are in your integration lifecycle.

Mode	Behavior	Use case
Monitor	Validates every transaction and logs the result, but never blocks. Invalid transactions produce warnings.	Initial rollout. Observe Shield's behavior against real production traffic without risk of false-positive disruption.
Defense	Validates every transaction and blocks any that fail. Invalid transactions are rejected before they reach the signing flow.	Production hardening. Active protection against tampering, with server-side enforcement. See Defense Mode for full details.