solana-serde-varint is used at run time in 121 crates (of which 1 optionally). It is a direct run-time dependency in 4 crates. It's used only as a dev dependency in 7 crates.

Depender (with downloads and own rev deps) solana-serde-varint version
1.1M 546 solana-program =2.1.0
1.1M 611 solana-sdk =2.1.0
67K 36 solana-version =2.1.0
11K 13 solana-gossip =2.1.0