Generates Go types based on JSON Schemas
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Generates Go struct types based on a JSON Schema.


$ go get


$ schematyper schema.json

Creates a schema_schematype.go file with package main.

Command line options:

usage: schematyper [<flags>] <input>

      --help                 Show context-sensitive help (also try --help-long and --help-man).
  -c, --console              output to console instead of file
  -o, --out-file=OUT-FILE    filename for output; default is <schema>_schematype.go
      --package="main"       package name for generated file; default is "main"
      --root-type=ROOT-TYPE  name of root type; default is generated from the filename
      --prefix=PREFIX        prefix for non-root types

  <input>  file containing a valid JSON schema

package main (the default) will generate unexported types. Any other package name defaults to exported types. --root-type and --prefix can be used to override this behavior.

Can be used with go generate:

//go:generate schematyper -o schema_type.go -package mypackage schemas/schema.json

Schema Features Support

Supports the following JSON Schema keywords:

  • title - sets type name
  • description - sets type comment
  • required - sets which fields in type don't have omitempty
  • properties - determines struct fields
  • additionalProperties - determines struct type of map values
  • type - sets field type (string, bool, etc.). Examples:
    • ["string", "null"] sets *string
    • "object" sets map[string]interface{}, map[string]<new type>, or a new struct type depending on schema
    • "array" sets []interface{} or []<new type> depending on schema
    • ["string", "integer"] sets interface{}
  • items - sets array items type, similar to type
  • format - if date-time, sets type to time.Time and imports time
  • definitions - creates additional types which can be referenced using $ref
  • $ref - Reference a local schema (same file).

Support for more features is pending, but many will require adding run-time checks by implementing the json.Marshaler and json.Unmarshaler interfaces.