fmt.Appendf
standard libraryThe 1236th most-called standard-library function by production calls. Called 1,243 times across 152 modules; 511 of those run outside tests and generated code.
5% in production calls vs 2026-W37 (487 → 511)
- prod calls
- 511
- non-test, non-generated
- all calls
- 1,243
- total callsites
- modules
- 152
- distinct callers
- in loop
- 21%
- of prod calls
- in tests
- 59%
- 732 calls
- resolved
- 100%
- to a known target
resolution mix
How each call resolves
How each call was attributed. Only resolved kinds, where the target function is known, count toward the ranking. Interface dispatch and unresolved receivers are reported separately and never guessed. Read the taxonomy →
- Package function100%A direct call to an exported package function, resolved by type.
who calls this
Notable callers
Production calls into Appendf from notable Go projects. Open one on the map to see what else it hammers.
- Go (golang.org/x) 39 8%
- NATS 33 6%
- Tailscale 24 5%
- Docker 23 5%
- Kubernetes 12 2%
where it's called
Callsites in the wild
12 representative callsites of 1,243, prioritizing in-loop and non-test usage. We link to source, never display it.
- in loop
- in loop
- in loop
- in loop
- in loop
- in loop
- in loop
-
coreos/go-systemd/v22 @v22.7.0
in loop - in loop
- in loop
- in loop
- in loop
top callers
The modules that reach for it
The modules that call Appendf most in this snapshot.
- github.com/nats-io/nats-server/v214712%
- github.com/moby/buildkit917%
- github.com/dapr/dapr565%
- github.com/ethereum/go-ethereum474%
- github.com/minio/minio474%
siblings
More from fmt
The other most-called functions in this package. See all →