JSON Marshal Library

By default, Hertz integrates with and uses Sonic for serializing ctx.JSON interface and deserialization requests as defined in the binding package. Sonic is an ultra-high performance golang json library, also see Sonic README for details.

The following are requirements to enable Sonic:

  • Go 1.15/1.16/1.17/1.18
  • Linux / darwin OS / Windows
  • Amd64 CPU with AVX instruction set

Sonic automatically fallback to golang’s encoding/json library when the above requirements have not been satisfied.

Compatibility With encoding/json

Currently, Hertz uses the default configuration for Sonic (i.e.sonic.ConfigDefault), which behaves different from JSON encoding/json. Specifically, by default, Sonic are configured to:

  • disable html escape: Sonic will not escape HTML’s special characters
  • disable key-sort by default: Sonic will not sort json in lexicographical order

To find more about the compatibility with encoding/json, you may want to see sonic#Compatibility. You may change Sonic’s behavior (e.g. behaving exactly the same way as encoding/json) by calling ResetJSONMarshaler for render.


Bringing Your Own JSON Marshal Library

If Sonic does not meet your needs, you may provide your own implementation by calling ResetJSONMarshal for render and ResetJSONUnmarshaler for binding.

import (


func main() {
    // Render

    // Binding

Common FAQs

Compilation Error on Mac M1

Unsupported CPU, maybe it’s too old to run Sonic

In most cases, this is because the go binary and/or build configuration is not consistent with ARM arch.

  • Go binary is not built for ARM64. Please use a go binary compiled for ARM64. You may encounter issues on go1.16 as compiler incorrectly links x86 files due to official bugs. Therefore, go1.17 or above is highly recommended.
  • GOARCH is set to amd64 i.e. GOARCH=amd64. You can either remove the flag or set its value to arm64.
  • Running go binary compiled for x86 with a translator (e.g. Rosetta). This is not supported yet.

Build constraints exclude all Go files in xxx

This is mostly because Sonic does not work on your go version. See sonic#Requirement for a list of supported go versions.