ERC-3643 Compliance Guide

ERC-3643, also known as T-REX (Token for Regulated EXchanges), is the leading standard for compliant security tokens on Ethereum and EVM-compatible chains. Unlike ERC-20 tokens, which allow unrestricted transfers, ERC-3643 tokens enforce transfer rules at the smart contract level. Before any transfer executes, the token contract queries a set of compliance contracts and an identity registry to verify that both the sender and the receiver meet the regulatory requirements for that specific asset.

The architecture consists of four layers: the token contract itself, an identity registry that maps addresses to on-chain identities, a set of compliance modules that encode transfer rules (such as maximum holder counts, geographic restrictions, or lock-up periods), and a trusted issuers registry that determines which identity claims are accepted. This layered design means that compliance logic can be updated without redeploying the token, and the same identity infrastructure can serve multiple tokens across different issuers.

Phyntec integrates ERC-3643 natively into the Package-Oriented Framework. Each compliance rule is a separate package that can be composed into a diamond, ensuring that compliance is not an afterthought bolted onto a generic token, but a first-class architectural concern embedded from day one.