This web app allows you to generate an ASN.1 schema for your JSON messages. With an ASN.1 schema you can serialize and validate your messages in a variety of formats - binary, XML and JSON.

What this tool is good for?
There are two scenarios in which this tool may be helpful.
  1. When your protocol matures, you will need a schema for it. This tool allows a quick way to develop a schema using your sample messages.
  2. If you know JSON better than you know ASN.1, you may describe your data in JSON, then convert this JSON into ASN.1 schema.
What are Encoding Instructions?
ASN.1 schemas not only define data structures, but may also govern data encoding (serialization) details. Encoding Instructions specifying such details, e.g.:
int count = 123; count INTEGER
count INTEGER [NAME Count]
Any hints?
  • To apply various schema generation options to various parts of a message split it into multiple objects and get several schemas , then re-combine schemas into one
  • Provide default values, it will allow more compact encodings
  • In an array do not use null to skip objects, use {} instead. ASN.1 arrays (SEQUENCE OF) have no notion of a null element