Core CCIP Concepts
This page defines the core, CCIP-specific primitives that appear throughout the CCIP architecture, token model, and messaging system.
It does not describe step-by-step workflows or configuration.
Entry points and primitives
Router
The CCIP Router is the primary onchain entry point for sending cross-chain messages and token transfers. Applications interact with the Router to initiate CCIP operations, while the Router forwards messages to the appropriate onchain and offchain components.
The Router provides a consistent interface for CCIP interactions across supported chains.
Cross-Chain Message
A cross-chain message is the fundamental unit of communication in CCIP. Messages can carry:
- data only,
- tokens only, or
- tokens combined with data.
Messages are verified offchain and executed on the destination chain according to CCIP’s messaging and execution model.
Lane
A lane represents a directional cross-chain pathway between a source chain and a destination chain. Each lane defines the execution context, operational state, and limits for messages and token transfers flowing in that direction.
Lanes are the unit at which availability, throughput, and status are tracked in CCIP.
OnRamp and OffRamp
OnRamp and OffRamp contracts handle the entry and exit of CCIP messages at the chain level.
- The OnRamp processes messages and token transfers on the source chain.
- The OffRamp executes messages and token transfers on the destination chain after verification.
Together, these components enforce ordering, execution guarantees, and interaction with downstream contracts.
Executor
The Executor is responsible for executing verified CCIP messages on the destination chain. Execution may involve calling application contracts, transferring tokens, or triggering additional logic as defined by the message payload.
Execution is asynchronous and subject to operational constraints such as gas limits and lane status.
Token movement and coordination
Programmable Token Transfer (PTT)
A Programmable Token Transfer (PTT) is a CCIP message that combines token transfers with application data, enabling tokens and instructions to arrive together on the destination chain.
PTTs are commonly used for cross-chain deposits, staking, swaps, and other workflows where value transfer and execution must be coordinated.
Cross-Chain Token (CCT)
A Cross-Chain Token (CCT) is a token configured to move across chains using CCIP. CCTs rely on token pools and defined transfer mechanisms to maintain supply consistency across networks.
CCTs can be used on their own or as part of Programmable Token Transfers.
Token Pool
A token pool manages liquidity and supply accounting for a Cross-Chain Token across chains. Token pools enforce transfer mechanisms such as lock-and-mint or burn-and-mint and apply rate limits to control flow.
Token pools are central to the safety and correctness of cross-chain token transfers.
Transfer Mechanisms
CCIP supports different transfer mechanisms for cross-chain tokens, including:
- Lock and Mint
- Burn and Mint
The transfer mechanism determines how token supply is managed across chains and how value is represented on each network.
Risk controls and extension points
Token Pool Rate Limits
Token pool rate limits constrain the amount of tokens that can move across a lane over a given period. These limits are designed to reduce risk and provide operational control over cross-chain token movement.
Rate limits are enforced at the pool level and may vary by token and lane.
Cross-Chain Verification (CCV)
A Cross-Chain Verification (CCV) defines how CCIP messages are verified before execution. The default CCIP verification model is provided by the CCIP network, while custom CCVs allow advanced teams to define alternative verification logic.
CCVs are an advanced extension point and are not required for most CCIP integrations.