Encoding & Decoding

Binary encoding helpers and decoding transactions in CosmJS

Encoding Utilities

@cosmjs/encoding provides conversions between common formats:

Function	Input	Output	Use case
toHex / fromHex	Uint8Array ↔ string	Hex strings	Transaction hashes, debug output
toBase64 / fromBase64	Uint8Array ↔ string	Base64 strings	Public keys, signatures in JSON
toUtf8 / fromUtf8	string ↔ Uint8Array	UTF-8 bytes	Amino sign docs, contract messages
toAscii / fromAscii	string ↔ Uint8Array	ASCII bytes	Printable ASCII only (0x20–0x7E)
toRfc3339 / fromRfc3339	Date ↔ string	ISO timestamps	Block times, governance deadlines

import { toHex, fromHex, toBase64, fromBase64, toUtf8, fromUtf8 } from "@cosmjs/encoding";

toHex(new Uint8Array([0xde, 0xad]));   // "dead"
fromHex("deadbeef");                    // Uint8Array [222, 173, 190, 239]

toBase64(new Uint8Array([1, 2, 3]));   // "AQID"
fromBase64("AQID");                     // Uint8Array [1, 2, 3]

toUtf8("hello");                        // Uint8Array [104, 101, 108, 108, 111]
fromUtf8(new Uint8Array([104, 101]));   // "he"

Decoding Transactions

You can decode raw transaction bytes back into structured data:

import { decodeTxRaw } from "@cosmjs/proto-signing";

const decoded = decodeTxRaw(txBytes);

// decoded.body.messages — Array<Any> (typeUrl + raw bytes)
// decoded.authInfo — fee and signer info
// decoded.signatures — raw signature bytes

To decode individual messages, use the registry:

import { Registry } from "@cosmjs/proto-signing";
import { defaultRegistryTypes } from "@cosmjs/stargate";

const registry = new Registry(defaultRegistryTypes);

for (const anyMsg of decoded.body.messages) {
  const msg = registry.decode({ typeUrl: anyMsg.typeUrl, value: anyMsg.value });
  console.info(anyMsg.typeUrl, msg);
}