JSON Serialization Libraries Performance Comparison
Article Summary
Israel Abramov from Just Eat Takeaway tested 10 JSON serialization libraries across 8 scenarios. The results? Your default serializer might be costing you serious performance.
Most .NET developers default to Newtonsoft.Json, but it has a fundamental inefficiency: it treats UTF-8 data as UTF-16, creating unnecessary overhead. This comprehensive benchmark tested execution time, memory allocation, and CPU usage across serialization and deserialization of both simple and complex objects.
Key Takeaways
- SpanJson dominated with best execution time and memory allocation across tests
- Newtonsoft.Json underperformed against newer alternatives like System.Text.Json
- Utf8Json and NetJSON showed remarkable speed but crash on circular references
- Memory allocation varied 10x between best and worst performers on complex objects
- System.Runtime.Serialization.Json ranked worst, avoid for production use
Critical Insight
Switching from Newtonsoft.Json to SpanJson, Utf8Json, or System.Text.Json can dramatically improve API performance with minimal code changes.
