Inspectors

Protobuf / ASN.1 Decoder

Decode protobuf wire format without needing the original .proto schema, or parse ASN.1 DER/BER TLV (Tag-Length-Value) structures. For protobuf, the tool walks the wire format and shows each field's number, wire type, and value — including nested messages. For ASN.1, it parses the TLV tree showing tags, lengths, and values. Useful for debugging gRPC payloads, inspecting X.509 certificate internals, or reverse-engineering binary protocols.

Protobuf / ASN.1 Decoder — Decode protobuf wire format (without schema) or parse ASN.1 DER/BER TLV structure

What it does

  • ▸Decodes protobuf wire format without a schema — shows field numbers, wire types, and values
  • ▸Recursively decodes nested protobuf messages
  • ▸Parses ASN.1 DER and BER TLV structures
  • ▸Shows the full TLV tree with tag, length, and value at each node
  • ▸Accepts hex or Base64 input
  • ▸Identifies common ASN.1 types (INTEGER, OCTET STRING, OID, SEQUENCE, etc.)

Use cases

  • ▸Debugging a gRPC payload by inspecting the raw protobuf wire format
  • ▸Inspecting the ASN.1 structure inside an X.509 certificate
  • ▸Reverse-engineering a binary protocol that uses protobuf
  • ▸Understanding the internal structure of a DER-encoded cryptographic object

How it works

1

Paste your hex or Base64 data into the input pane

2

Choose Protobuf or ASN.1 decode mode

3

The tool parses the binary structure and displays it as a tree

4

Review field numbers, wire types, tags, and values in the output

Frequently asked questions

1Can it decode protobuf without the .proto file?

Yes. The tool decodes the wire format directly — it shows field numbers and wire types (varint, 64-bit, length-delimited, 32-bit) without needing the schema. You won't get field names, but you can see the structure and values. Length-delimited fields that look like nested messages are recursively decoded.

2What's ASN.1 and why would I need to decode it?

ASN.1 (Abstract Syntax Notation One) is a binary encoding used in X.509 certificates, LDAP, SNMP, and cryptographic standards. DER and BER are encoding rules for ASN.1. If you're debugging certificates, PKI, or cryptographic protocols, being able to inspect the raw TLV structure is essential.

3What input format does it accept?

Hex (with or without spaces, 0x prefixes) or Base64. The tool detects the format automatically or you can specify it. The decoded bytes are then parsed as protobuf wire format or ASN.1 TLV depending on the mode.

Related tools

Hexdump Viewer — Display text, hex, or base64 data as a classic hexdump with offset, hex bytes, and ASCII

Hexdump Viewer

Display text, hex, or base64 data as a classic hexdump with offset, hex bytes, and ASCII

Hex ⇄ Text — Convert between text and hexadecimal bytes (UTF-8)

Hex ⇄ Text

Convert between text and hexadecimal bytes (UTF-8)

Certificate Decoder (X.509) — Decode a PEM certificate — subject, issuer, validity, SANs, fingerprints

Certificate Decoder (X.509)

Decode a PEM certificate — subject, issuer, validity, SANs, fingerprints

Base64 String Encode/Decode — Encode and decode Base64 strings (unicode-safe)

Base64 String Encode/Decode

Encode and decode Base64 strings (unicode-safe)

Use Protobuf / ASN.1 Decoder offline in Devinity

All 95 tools run locally on your Mac. No internet required, no data sent to servers.

Download Devinity →