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See what your dependencies call most

Every dot is a function, placed by how often it’s called in production and how much of that runs inside a loop. Put on a project lens, say Kubernetes, and the map redraws to what that codebase calls, with its own loop shares. Search, filter, click through to any function.

Project lens
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Package
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0%25%50%75%100%1kproduction calls (log scale)share of calls in a loopNewErrorfTrimSpaceContainsHasPrefixSprintfSplitBuilder.WriteStringMutex.Lock
coolhot in-loop prod callsringed = hottest38 functions across the corpus

Drag a box on the chart to zoom; double-click to reset. Or use the zoom controls. Volume = production calls.

Show the 38 plotted functions as a list
  1. fmt.Errorf8,402 · 18%
  2. fmt.Sprintf7,511 · 11%
  3. errors.New5,590 · 31%
  4. strings.Contains3,711 · 27%
  5. strings.TrimSpace3,393 · 35%
  6. strings.Split2,984 · 25%
  7. context.WithValue2,660 · 17%
  8. strings.HasPrefix2,526 · 33%
  9. strings.Builder.WriteString2,231 · 30%
  10. fmt.Fprintf2,112 · 18%
  11. strconv.Itoa1,895 · 12%
  12. bytes.Buffer.WriteString1,785 · 19%
  13. github.com/sirupsen/logrus.WithField1,669 · 22%
  14. sync.Mutex.Lock1,486 · 34%
  15. encoding/json.Marshal1,470 · 12%
  16. reflect.TypeOf1,312 · 24%
  17. regexp.MustCompile1,311 · 5%
  18. strconv.ParseInt1,137 · 12%
  19. sort.Slice1,115 · 20%
  20. time.Now1,085 · 6%
  21. io.Writer.Write1,039 · 15%
  22. io.Reader.Read1,024 · 18%
  23. regexp.Regexp.MatchString1,010 · 36%
  24. error.Error902 · 9%
  25. sync.WaitGroup.Add869 · 26%
  26. net/http.NewRequest809 · 6%
  27. encoding/json.Unmarshal804 · 18%
  28. k8s.io/apimachinery/pkg/util/sets.New799 · 36%
  29. path/filepath.Join767 · 14%
  30. fmt.Stringer.String704 · 17%
  31. github.com/spf13/cobra.Command.Flags652 · 13%
  32. google.golang.org/protobuf/proto.Marshal642 · 19%
  33. context.Context.Done628 · 25%
  34. os.Getenv580 · 24%
  35. bufio.Scanner.Scan561 · 65%
  36. strings.Join522 · 30%
  37. sort.Interface.Less402 · 47%
  38. gopkg.in/yaml.v2.Unmarshal300 · 10%

Colour is heat, how many of a function’s production calls land inside loops. The ringed, labelled functions run both hot and often, which is where a profiler is most likely to agree. Static counts aren’t runtime cost. Snapshot 2026-07-sample.