solana-system-interface is used at run time in 293 crates (of which 25 optionally). It is a direct run-time dependency in 33 crates. It's used only as a dev dependency in 43 crates (of which 6 directly).

Depender (with downloads and own rev deps) solana-system-interface version
441K 78 spl-token-2022 ^1.0.0
340K 601 solana-program ^1.0
139K 15 solana-config-program ^1.0
128K 8 solana-stake-interface ^1.0
127K 2 spl-elgamal-registry ^1.0.0
123K 131 solana-transaction-status ^1.0
122K 2 solana-example-mocks ^1.0
113K 3 solana-thin-client ^1.0
98K 5 solana-client-traits ^1.0
94K 12 solana-system-transaction ^1.0
59K 20 solana-address-lookup-table-program ^1.0
128K 45 solana-message optional ^1.0
126K 5 solana-vote-interface optional ^1.0
125K 4 solana-feature-gate-interface optional ^1.0
123K 9 solana-loader-v3-interface optional ^1.0
123K 6 solana-loader-v4-interface optional ^1.0
39K 22 solana-bpf-loader-program ^1.0
39K 10 solana-system-program ^1.0
112K 26 solana-perf optional ^1.0
101K 40 solana-transaction optional ^1.0
31K 5 solana-cost-model ^1.0
29K 11 solana-faucet ^1.0
17K 27 solana-cli-output ^1.0
2.3K 4 litesvm ^1
1.6K 3 solana-cli ^1.0
310 1 spherenet-stake-interface ^1.0
150 litesvm-token ^1
100 spherenet-program ^1.0
198K 14 solana-cpi dev ^1.0
196K 15 solana-bincode dev ^1.0
113K 3 solana-rpc-client-nonce-utils dev ^1.0
99K 29 solana-transaction-context dev ^1.0
80K 47 solana-clap-utils dev ^1.0
21K 12 solana-svm-transaction dev ^1.0
19K 3 agave-transaction-view dev ^1.0
20K 12 solana-runtime-transaction dev ^1.0
16K 10 solana-clap-v3-utils dev ^1.0
12K 6 solana-compute-budget-instruction dev ^1.0
1.6K 6 mollusk-svm dev ^1.0