# CCIP Onchain Architecture (TON)
Source: https://docs.chain.link/ccip/concepts/architecture/onchain/ton
Last Updated: 2026-04-07

> For the complete documentation index, see [llms.txt](/llms.txt).

Chainlink CCIP's TON onchain architecture consists of specialized Tolk contracts deployed on both source and destination chains. These contracts work together with CCIP's offchain infrastructure to provide end-to-end cross-chain interoperability.

- **[Overview](/ccip/concepts/architecture/onchain/ton/overview)**: Provides a high-level introduction to CCIP's TON-based onchain architecture, including a component diagram, key roles, and a detailed walk-through of a message's lifecycle from source to destination chain.

- **[Components](/ccip/concepts/architecture/onchain/ton/components)**: Describes each architectural component in detail.

- **[Upgradability](/ccip/concepts/architecture/onchain/ton/upgradability)**: Explains CCIP's approach to secure system evolution.