YAML to Base64 Converter

Base64 does not read or change your YAML. It takes the file’s bytes, exactly as saved, and writes them using only letters, digits, +, / and =. The result fits on one line with no spaces, colons or quotes, so it can sit safely inside another file or a variable. Comments, indentation and key order all come back untouched when you decode it.

1. Paste the YAML into the box above, or open the file in a text editor and copy all of it.
2. Leave the output on One line, which is what Kubernetes, GitHub Actions and most tools expect.
3. If you want the same result as running base64 on the file, turn on + final newline. Saved files almost always end with one.
4. Copy the Base64. To check it, switch to Base64 → YAML and the original comes back.

To do it from a terminal instead:

On Linux, -w 0 matters: without it the output is broken into lines of 76 characters, and most places you paste it into expect a single line. macOS does not wrap unless you ask. The Windows commands run in PowerShell and read the file’s bytes directly, so nothing is added or changed.

The usual reason to Base64-encode YAML is to store a whole config file as a single value. In a Kubernetes Secret, every value under data must be Base64. Here a two-line config.yaml (with its final newline) becomes one value:

apiVersion: v1
kind: Secret
metadata:
  name: app-config
type: Opaque
data:
  config.yaml: bG9nX2xldmVsOiBpbmZvCnBvcnQ6IDgwODAK

You often do not need to encode by hand. These do it for you:

• kubectl create secret generic app-config --from-file=config.yaml reads the file and encodes it, final newline included.
• Put the plain YAML under stringData instead of data, using a | block, and Kubernetes encodes it when you apply the manifest.

To read a value back out, decode it:

kubectl get secret app-config -o jsonpath='{.data.config\.yaml}' | base64 -d

CI systems work the same way. A kubeconfig or a multi-line config is easier to store as a GitHub Actions or GitLab CI secret once it is one line of Base64, and GitHub’s documentation recommends Base64 for storing blobs as secrets. Encode it with base64 -w 0 kubeconfig.yaml, save the output as a secret, then decode it in the job:

- run: echo "$KUBECONFIG_B64" | base64 -d > kubeconfig.yaml
  env:
    KUBECONFIG_B64: ${{ secrets.KUBECONFIG_B64 }}

GitHub limits each secret to 48 KB, and Base64 is about a third bigger than the file, so a YAML file of up to roughly 36 KB fits.

If two tools give different Base64 for the same YAML, they were given different bytes. The text looks the same on screen, but something invisible differs. These are the usual causes:

The byte-order mark usually comes from Windows PowerShell 5 (-Encoding utf8 on Set-Content or Out-File) or from older editors. Kubernetes and most YAML tools cope with it, but it changes the Base64. Plain Out-File and > are worse: they save UTF-16, which doubles the size and starts the Base64 with //. Decoding a value in this tool shows whether it had a byte-order mark or Windows line endings, and flags UTF-16.