What is the fastest way to parse large JSON files in Go?

For large JSON files in Go, use json.Decoder with streaming for maximum efficiency: decoder := json.NewDecoder(file); decoder.Decode(&data) reads incrementally without loading entire file into memory. For massive files, process arrays element-by-element using decoder.Token() for manual streaming. Libraries like jsoniter offer 2-3x faster parsing than standard library through optimized implementations. Use json.RawMessage to defer parsing of unused sections. Enable DisallowUnknownFields() only when necessary as it slows parsing. For extreme performance, consider ffjson or easyjson which generate optimized unmarshaling code. Parallel processing with goroutines can parse independent JSON objects concurrently. Use bufio.Reader with large buffer sizes to reduce I/O overhead. Memory mapping very large files improves access patterns. Profile with pprof to identify bottlenecks. Validate your JSON structure first using our JSON Validator at jsonconsole.com/json-editor before implementing streaming. Choose approach based on file size: standard decoder under 100MB, streaming for larger files, specialized libraries for critical performance.