---
title: Use environment variables in Telegraf configurations
description: Substitute environment variables anywhere in the Telegraf configuration file with ${VAR} syntax, including shell parameter expansion forms for defaults and required variables.
url: https://docs.influxdata.com/telegraf/v1/configuration/environment-variables/
estimated_tokens: 631
product: Telegraf Enterprise
version: v1
publisher: InfluxData
canonical: https://docs.influxdata.com/telegraf/v1/configuration/environment-variables/
date: '2026-08-14T12:27:55-06:00'
lastmod: '2026-08-14T12:27:55-06:00'
---

Use environment variables anywhere in the configuration file by enclosing
them in `${}`.
Telegraf replaces variables before parsing the file, so a variable can supply
any part of the configuration.

Quoting follows the TOML type of the value:

* For strings, put the variable inside quotes, such as `"${STR_VAR}"`.
* For numbers and booleans, leave the variable unquoted, such as`${INT_VAR}` or `${BOOL_VAR}`.
* In double-quoted strings, escape backslashes, such as`"C:\\Program Files"`.
  For values that contain a single backslash, use a single-quoted literal
  string, such as `'C:\Program Files'`.
  See[Basic strings and literal strings](/telegraf/v1/configuration/toml/#basic-strings-and-literal-strings).

> [!Note]
> For credentials, consider [secret stores](/telegraf/v1/configuration/secrets/)instead of environment variables. Secrets are resolved at runtime and
> protected in memory.

## Expansion forms

Telegraf supports shell parameter expansion for environment variables:

* **`${VARIABLE}`**: the value of `VARIABLE`.
* **`${VARIABLE:-default}`**: `default` if `VARIABLE` is unset or empty.
* **`${VARIABLE-default}`**: `default` only if `VARIABLE` is unset.
* **`${VARIABLE:?err}`**: exits with an error message containing `err` if`VARIABLE` is unset or empty.
* **`${VARIABLE?err}`**: exits with an error message containing `err` if`VARIABLE` is unset.

## Where to define variables

Define variables in the environment that starts Telegraf, such as your shell,
a systemd unit, or a container environment.
When using the `.deb` or `.rpm` packages, define environment variables in`/etc/default/telegraf`.
The service reads this file at startup.

## Example

Define the variables:

```sh
# /etc/default/telegraf
INFLUX_HOST="http://localhost:8181"
INFLUX_TOKEN="replace_with_your_token"
INFLUX_DATABASE="telegraf"
```

Reference them in the configuration file:

```toml
[global_tags]
  user = "${USER}"

[[inputs.mem]]

[[outputs.influxdb_v3]]
  urls = ["${INFLUX_HOST}"]
  token = "${INFLUX_TOKEN}"
  database = "${INFLUX_DATABASE}"
```

After substitution, Telegraf parses the effective configuration:

```toml
[global_tags]
  user = "alice"

[[inputs.mem]]

[[outputs.influxdb_v3]]
  urls = ["http://localhost:8181"]
  token = "replace_with_your_token"
  database = "telegraf"
```

#### Related

* [Use secrets in Telegraf configurations](/telegraf/v1/configuration/secrets/)
* [Telegraf configuration file](/telegraf/v1/configuration/file/)
* [TOML syntax for Telegraf](/telegraf/v1/configuration/toml/)