Decode from base64: base64_decode

The base64_decode filter takes a base64-encoded string and decodes it back to its original form. By default, it returns a UTF-8 string, but you can set the encoding to none to get raw bytes instead.

This is useful when you receive base64-encoded data from external services or sensorsSensors return information about a thing, for instance the level of water in a tank. [Learn more]. For example, some MQTT messages include base64-encoded payloads, certain APIs return data in base64 format, or you might receive encoded credentials that need to be decoded. The optional encoding parameter lets you control how the decoded bytes are interpreted. Set it to none when working with binary data that is not a text string.

Usage

Here’s how to use this template function. Copy any example and adjust it to your setup.

{{ "SGVsbG8sIFdvcmxkIQ==" | base64_decode }}

Hello, World!

Function signature

The signature is a technical summary of this template function. It shows the name of the function, the values (called parameters) it accepts, and what type of data each parameter expects (for example, a piece of text or a number).

Function parameters that have a = with a value after them are optional. If you leave them out, the default value shown is used automatically.

Function parameters without a = are usually required. A few optional parameters have no default value, so the signature shows them without a = as well. To check whether a parameter is required, look at the parameter list below the signature. Each parameter is marked as Required or Optional.

The most common optional parameter without a default value is default. The default parameter sets the value a function returns when the function can’t produce a result, for example, when float gets text that isn’t a number. If you leave out default, there is no fallback value, so most functions raise an error and the template fails. The parameter list of each function says what happens. If you set default, the function returns your value instead.

round(
    value: Any,
    precision: int = 0,
    method: str = "common",
    default: Any,
) -> float | int | Any

value | base64_decode(
    encoding: str | None = "utf-8",
) -> str | bytes

Function parameters

The following parameters can be provided to this filter.

Decoding to raw bytes

Set encoding to none to get the raw bytes instead of a string. This is useful when the encoded data is not text.

{{ "AQIDBA==" | base64_decode(encoding=none) }}

b'\x01\x02\x03\x04'

Good to know

• By default, the decoded bytes are interpreted as UTF-8. Non-UTF-8 binary data raises an error unless you pass encoding=none.
• Setting encoding=none returns raw bytes, which display with a b'...' prefix and cannot be concatenated with strings directly.

Try it yourself

Ready to test this? Open Settings > Tools > Template, paste the example into the Template editor, and watch the result update on the right. Edit the values to see how the function adapts to your own entitiesAn entity represents a sensor, actor, or function in Home Assistant. Entities are used to monitor physical properties or to control other entities. An entity is usually part of a device or a service. [Learn more].

More examples

Real scenarios where this function comes up in automations and templates. Copy any example and adapt it to your setup.

Decode an MQTT payload

Decode a base64-encoded message received from an MQTT topic.

{{ states("sensor.mqtt_encoded") | base64_decode }}

Temperature: 21.5C

Decode and parse JSON

Decode a base64 string that contains JSON data, then parse it.

{% set decoded = "eyJ0ZW1wIjogMjEuNX0=" | base64_decode %}
{{ decoded | from_json }}

{'temp': 21.5}

Still stuck?

The Home Assistant community is quick to help: join Discord for real-time chat, post on the community forum with your template and expected result, or share on our subreddit /r/homeassistant.

Related template functions

These functions work well alongside this one:

• Encode to base64: base64_encode - Encodes a string or bytes to a base64 string.