ASN.1 Playground - learn, play, test
For a limited time, OSS will analyze your ASN.1 schema and help with your messages, all at no cost.

The place where you can have fun experimenting with ASN.1 right in your browser. It compiles, it encodes, it decodes! It's free!


Select the ASN.1 specification (enter manually, upload new, or pick existing). Compile to check the syntax and to extract the data Types to be used in Decoding and Encoding.

Data: Decode

Select the Type. Upload a message/PDU/record file. Click Decode. The decoded data can be downloaded as a text file in the ASN.1 Value Notation format.

Decoded as:  TXT

Data: Encode

Enter a Value (in the ASN.1 Value Notation format) for one of the Types defined in the Schema. Click Encode. Various encoded formats will be available as links for downloading.

Sample Value:

Console Output


Please compile your schema

1. You can decode a BER/DER message without providing the schema. In such a case, the decoder will output only Type-Length-Value information.
2. Decoding relies on file extensions matching the ASN.1 encoding rules that a message conforms to (.ber for BER, .per for PER, .xml for XML, etc.)
3. PER/UPER decoding prints bit-wise details of the message. Sequences of bits are shown using the format <bbb>.xx.xx, where 'b' is for bits, 'x' is for hex and '.' indicates byte boundary. A pair of digits (e.g. OFFSET: 5,2) indicates bytes and bits (e.g. five bytes, two bits).
4. If you have an ASN.1 schema that contains multiple modules (BEGIN ... END blocks), the Playground will work with it too.
5. Upload schemas that consist of multiple .asn files by concatenating files together.