> ## Documentation Index
> Fetch the complete documentation index at: https://cosmos-docs-cosmjs-docs.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# 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  |

```typescript theme={"system"}
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:

```typescript theme={"system"}
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:

```typescript theme={"system"}
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);
}
```