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Secrets in Doppler work very similarly to how they would on any other platform, with a few exceptions. Our secrets engine has a couple of built-in perks!

Secret Names

Secret names must adhere to a specific format:

  • Secret names may only contain uppercase letters, numbers, and underscores
  • Secret names may not start with a number

For example, DATABASE_URL is a valid secret name while 1secret_name is not.

This strict format ensures that your secrets will work as expected when injected into an environment (regardless of the shell).

Doppler CLI

See our dedicated Doppler CLI User Guide to learn how to get started managing secrets from the command line.

Secret Notes

Now Doppler can centralize your documentation for app secrets and config by providing a notes field for every secret, scoped at the project level.

Multi-line Secrets

Doppler supports multi-line secrets such as PEM and SSH keys. These can be copy and pasted directly into the Doppler dashboard, or you can add them via the CLI:

cat ./id_rsa | doppler secrets set SSH_KEY

You can then supply multi-line secrets to your application as environment variables by using doppler run or saving the secret to a file:

doppler secrets get SSH_KEY --plain > ./id_rsa

You can also use the Doppler CLI to create a Kubernetes TLS secret without a manifest file and the secrets ever touching the file system:

kubectl create secret tls doppler-test \
  --cert <(doppler secrets get CERT_PEM --plain) \
  --key <(doppler secrets get KEY_PEM --plain)


Multi-line Environment Variables for Every Language

Using doppler run to supply multi-line environment variables works flawlessly in every language and is one of the major benefits customers enjoy compared with .env files where multi-line support is patchy and incomplete at best.

This is great for scenarios where your application only reads the secrets once at runtime. By specifying a max reads value of 1, that will ensure that the file doesn't exist in the event an unauthorized actor gains access to the environment.

Referencing Secrets

The Doppler engine supports referencing secrets with the straightforward pattern ${SECRET_NAME}. Here is an example:









Now, when we access the WEBSITE secret, the USER and PORT secrets will be inserted.

$ doppler secrets --raw

β”‚ NAME    β”‚ VALUE                  β”‚ RAW                         β”‚
β”‚ PORT    β”‚ 3030                   β”‚ 3030                        β”‚
β”‚ USER    β”‚ brian                  β”‚ brian                       β”‚
β”‚ WEBSITE β”‚ β”‚ ${USER}${PORT} β”‚

Referencing Across Projects

For workplaces on paid plans you can reference secrets across configs and projects. Users can only reference secrets they have access to, however secrets already being referenced will remain.



Same config


Across configs


Across projects


Now lets see this in practice! Here is what it would look like to reference the STRIPE_API_KEY secret in the billing project in the prd config.



Same config


Across configs


Across projects


Reserved Secrets

Doppler has a few special secrets you can use which makes it easier to track where you are in your CI/CD pipeline.





Identifier of current project



Identifier of the current environment



Name of the current config


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