solana-cpi is used at run time in 121 crates (of which 1 optionally). It is a direct run-time dependency in 3 crates. It's used only as a dev dependency in 6 crates.

Depender (with downloads and own rev deps) solana-cpi version
1.1M 546 solana-program =2.1.0
195K 5 spl-transfer-hook-interface ^2.1.0
38K spl-instruction-padding ^2.1.0