solana-system-interface is used at run time in 182 crates (of which 14 optionally). It is a direct run-time dependency in 29 crates. It's used only as a dev dependency in 38 crates (of which 6 directly).

Depender (with downloads and own rev deps) solana-system-interface version
309K 597 solana-program ^1.0
139K 15 solana-config-program ^1.0
125K 128 solana-transaction-status ^1.0
115K 3 solana-thin-client ^1.0
93K 7 solana-stake-interface ^1.0
88K 1 solana-example-mocks ^1.0
73K 5 solana-client-traits ^1.0
70K 12 solana-system-transaction ^1.0
58K 20 solana-address-lookup-table-program ^1.0
39K 22 solana-bpf-loader-program ^1.0
39K 10 solana-system-program ^1.0
114K 26 solana-perf optional ^1.0
34K 11 solana-faucet ^1.0
32K 5 solana-cost-model ^1.0
93K 41 solana-message optional ^1.0
91K 3 solana-feature-gate-interface optional ^1.0
91K 4 solana-vote-interface optional ^1.0
90K 8 solana-loader-v3-interface optional ^1.0
89K 5 solana-loader-v4-interface optional ^1.0
76K 38 solana-transaction optional ^1.0
18K 27 solana-cli-output ^1.0
2.2K 4 litesvm ^1
1.5K 2 solana-cli ^1.0
150 litesvm-token ^1
166K 9 solana-cpi dev ^1.0
165K 14 solana-bincode dev ^1.0
116K 3 solana-rpc-client-nonce-utils dev ^1.0
85K 47 solana-clap-utils dev ^1.0
76K 19 solana-transaction-context dev ^1.0
19K 12 solana-svm-transaction dev ^1.0
18K 3 agave-transaction-view dev ^1.0
19K 12 solana-runtime-transaction dev ^1.0
16K 10 solana-clap-v3-utils dev ^1.0
9.1K 6 solana-compute-budget-instruction dev ^1.0
950 5 mollusk-svm dev ^1.0