---
title: digest.base64url
summary: null
url: >-
  https://www.fastly.com/documentation/reference/vcl/functions/cryptographic/digest-base64url
---

```
STRING digest.base64url(STRING s)
```

**Available in:** all subroutines

Returns a Base64-encoded representation of the string `s` that is suitable
for use in URLs and is suitable for decoding by
`digest.base64url_decode()`.
For URL-safety, instances of `+` are replaced with `-` and
instances of `/` are replaced with `_`.

The alphabet used is:

```
ABCDEFGHIJKLMNOPQRSTUVWXYZ
abcdefghijklmnopqrstuvwxyz
0123456789-_
```

The output string is padded to a multiple of four characters in length
using the `=` character.

See `digest.base64_decode()`
for details on the structure of Base64 encoding. In particular,
note that it is possible for two input strings to encode to the same
Base64 string.

## Example

```vcl
declare local var.base64url_encoded STRING;
set var.base64url_encoded = digest.base64url("Καλώς ορίσατε");
# var.base64url_encoded is now "zprOsc67z47PgiDOv8-Bzq_Pg86xz4TOtQ=="
```