> For the complete documentation index, see [llms.txt](https://docs.t-rex.network/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.t-rex.network/welcome.md). # Welcome T-REX is an open-source protocol for issuing, holding and transferring regulated assets on-chain. It is designed so that the on-chain contract can be the primary register of the asset: the record of who owns what, which also enforces who may own it, on every chain the asset reaches. Whether that record is also the legal register of a given asset depends on the jurisdiction and on the asset. Where the legal register has to be kept elsewhere, it follows what happens on T-REX. The protocol does three things: * It gives every participant a portable on-chain identity, an ONCHAINID. An ONCHAINID is a smart account: it carries verifiable credentials, it holds assets directly, and it links any number of wallets. * It records ownership in a permissioned ERC-3643 token that checks eligibility and compliance before a position changes hands. * It lets an asset circulate on many chains while one reference chain keeps the complete register and authorizes every movement. ## The names used in these docs | Name | What it is | | ------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | **T-REX protocol** | The smart contracts documented here: the identity layer (ONCHAINID), the token suite (token, eligibility registry, compliance) and the cross-chain messaging endpoint. | | **ONCHAINID** | The identity layer. An ONCHAINID is an ERC-7579 smart account that holds keys and claims. It can hold tokens itself, and wallets can be linked to it. | | **T-REX Ledger** | The reference chain: the chain on which the full protocol is deployed and which holds the golden copy of every asset and every identity. These docs define it by that role and by nothing else. | | **Satellite chain** | Any other chain on which an asset is made available. Also called a distribution chain. | | **T-REX Lite** | The lightweight token that represents an asset on a satellite chain. It holds balances and executes only the transfers the reference chain has authorized. | | **T-REX AppStore** | The directory of the applications available in the T-REX ecosystem. Applications are built on the protocol by their own providers. DINO (shared primary and secondary market contracts) and T-REX Engine (an API for identity, asset and distribution operations), both provided by Tokeny, are two of them. | | **T-REX Network** | The neutral, open-standards infrastructure formed by the protocol, its reference chain, the satellites connected to it and the AppStore. It is not a single chain. | > **Protocol first.** Everything in these docs is a property of the contracts. Nothing depends on which chain hosts the T-REX Ledger. ## How these docs are organized | Section | What you find there | | ---------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | **Start here** | This page, the architecture on one page, the standards the protocol is built from, the actors and their roles, and what changed since ERC-3643 v4. | | **Concepts** | How the protocol works and why: the primary register, identity, the token and its register, cross-chain distribution, governance and infrastructure, the security and trust model. | | **Guides** | One page per operation, with the actors, the calls, what the contracts check and what can fail. Grouped by who performs the operation, with [journeys](/guides/journeys.md) that order them end to end. | | [**Build**](/build.md) | Integration guides for wallets, custodians, venues, applications and Claim Issuers, and for writing compliance modules, gateway adapters and T-REX Lite implementations. | | [**AppStore**](/appstore.md) | The applications available in the ecosystem, what each one does, who provides it, and how it uses the protocol. | | **Reference** | One page per contract: functions, events, errors, roles. | | **Resources** | Deployments, whitepaper, glossary, FAQ, changelog, security and community. | ## Where to start | If you are | Read first | | ------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Structuring or issuing an asset | [Protocol at a glance](/start-here/protocol-at-a-glance.md), then [The primary register](/the-primary-register.md), then [J1 Issuer journey: launch an asset](/guides/journeys/j1.-issuer-journey-launch-an-asset.md) | | Integrating a wallet, a custodian, a venue or an application | [Protocol at a glance](/start-here/protocol-at-a-glance.md), then [Eligibility and compliance: the two gates](/the-primary-register/eligibility-and-compliance-the-two-gates.md) and [The permissioned token](/token-and-register/the-permissioned-token.md), then [Build](/build.md), starting with the [Quickstart](/build/quickstart.md) | | Verifying investors and issuing claims | [Actors and roles](/start-here/actors-and-roles.md), then [Claims: issuance, validity, revocation](/identity-onchainid/claims-issuance-validity-revocation.md) and [Claim issuers, trust and reputation](/identity-onchainid/claim-issuers-trust-and-reputation.md), then Build: Integrate as a Claim Issuer | | Reviewing or auditing the protocol | [Standards foundation](/start-here/standards-foundation.md), then Concepts: Security and trust model, then Reference | | Already running ERC-3643 v4 | [Coming from ERC-3643 v4](/start-here/coming-from-erc-3643-v4.md) | ## Source code and audits | Component | Version | Repository | Package | Audit | | ----------------------------------------------------- | ------- | --------------------------------------------------------------------- | -------------------------- | ------------------------------------------------------------------------------------------------------ | | T-REX (token suite, compliance, cross-chain endpoint) | 5.0.0 | [T-REX-Network/T-REX](https://github.com/T-REX-Network/T-REX) | `@t-rex-network/t-rex` | Audit in progress. See [Audits and verification](/security-and-trust-model/audits-and-verification.md) | | ONCHAINID (identity layer) | 3.0.0 | [T-REX-Network/ONCHAINID](https://github.com/T-REX-Network/ONCHAINID) | `@t-rex-network/onchainid` | [OpenZeppelin, ONCHAINID Audit](https://www.openzeppelin.com/news/onchainid-audit) | Both codebases are licensed under GPL-3.0 and built with Foundry (Solidity 0.8.30). Copyright (C) 2026 Digital Asset Operational Services ISAC Ltd. ("T-REX Network"). The contracts that implement ERC-3643 directly, in the `contracts/ERC-3643` folder of the T-REX repository, derive from Tokeny's work and keep Tokeny's copyright. The ERC-3643 interface files in that folder are published under CC0-1.0. Report a vulnerability to `security@trex.network`. Do not open a public issue for a security finding. ## Conventions * **Identity, wallet, holder address.** An identity is an ONCHAINID: a smart account that holds keys and claims and that can hold tokens itself. A wallet is any other address linked to an identity: an externally owned account, a smart-contract wallet, an address on another chain. Token functions take addresses. Eligibility and ownership are evaluated on the identity the address resolves to: a linked wallet resolves to its identity, and an identity resolves to itself. Every page says which one it means. * **Names in code font are exact.** `Token`, `TREXRegistry`, `requestTransferValidation` are the names in the source. Where a name is not settled, the page shows a `[[TBC]]` marker instead of a guess. * **Two gates.** Eligibility answers whether an identity may hold the asset. Compliance answers whether a specific movement may happen now. The docs never merge them. * **Present tense.** Pages describe how the protocol works, as designed. --- # Agent Instructions This documentation is published with GitBook. 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