go data_error ai_generated true

error: json: cannot unmarshal number 99999999999999999999 into Go value of type int64

ID: go/encoding-json-unmarshal-number-overflow

Also available as: JSON · Markdown · 中文
80%Fix Rate
82%Confidence
0Evidence
2026-07-20First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
1.20 active — — —
1.21 active — — —

Root Cause

A JSON number exceeds the range of the target Go integer type, causing overflow.

generic

中文

JSON数字超出目标Go整数类型的范围，导致溢出。

Workarounds

  1. 90% success Use json.Number or big.Int for large numbers 
    var num json.Number
if err := json.Unmarshal(data, &num); err != nil { return err }
intVal, _ := num.Int64()

Dead Ends

Common approaches that don't work:

  1. Using float64 to store large numbers 50% fail

    May lose precision for very large integers; use big.Int or string.