Cross Program Invocation

A Cross Program Invocation (CPI) is a mechanism that allows Solana programs to call other programs from within an instruction. The caller is halted until execution returns from the callee.

Programs can extend their signer privileges to other programs using CPIs. CPIs are executed by calling either invoke or invoke_signed methods within their instructions:

• invoke - All necessary signatures are already available before the call.
• invoke_signed - Calling program needs PDAs to act as signers during the CPI.

CPIs are a very powerful feature as they allow developers to make use of other deployed programs and continuously build on and expand the Solana's already existing ecosystem.