solana-serde-varint is used at run time in 228 crates (of which 8 optionally). It is a direct run-time dependency in 4 crates. It's used only as a dev dependency in 12 crates.

Depender (with downloads and own rev deps) solana-serde-varint version
1.4M 546 solana-program =2.1.0
1.4M 608 solana-sdk =2.1.0
68K 36 solana-version =2.1.0
11K 13 solana-gossip =2.1.0