---
page_title: base64decode - Functions - Configuration Language
description: The base64decode function decodes a string containing a base64 sequence.
---

# `base64decode` Function

`base64decode` takes a string containing a Base64 character sequence and
returns the original string.

Packer uses the "standard" Base64 alphabet as defined in
[RFC 4648 section 4](https://tools.ietf.org/html/rfc4648#section-4).

Strings in the Packer language are sequences of unicode characters rather
than bytes, so this function will also interpret the resulting bytes as
UTF-8. If the bytes after Base64 decoding are _not_ valid UTF-8, this function
produces an error.

While we do not recommend manipulating large, raw binary data in the Packer
language, Base64 encoding is the standard way to represent arbitrary byte
sequences, and so resource types that accept or return binary data will use
Base64 themselves, which avoids the need to encode or decode it directly in
most cases. Various other functions with names containing "base64" can generate
or manipulate Base64 data directly.

## Examples

```shell-session
> base64decode("SGVsbG8gV29ybGQ=")
Hello World
```

## Related Functions

- [`base64encode`](/packer/docs/templates/hcl_templates/functions/encoding/base64encode) performs the opposite operation,
  encoding the UTF-8 bytes for a string as Base64.
