> ## Documentation Index
> Fetch the complete documentation index at: https://docs.openlayer.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Environment Variables

> Learn how to use workspace and project environment variables.

Environment variables allow you to securely store API keys and other sensitive configuration values.

These variables are used in [development mode](/development/overview), when running your scripts,
and for [LLM-based tests](/tests/catalog/l-l-m-rubric-threshold),
such as LLM-as-a-judge evaluations.

## Workspace-level environment variables

Workspace-level environment variables are shared across **all projects** in your workspace.

To set them, navigate to **Workspace settings** → **Environment variables**.

### Pre-defined variables

Openlayer provides pre-defined fields for commonly used API keys:

* `OPENAI_API_KEY`
* `ANTHROPIC_API_KEY`
* `AZURE_OPENAI_API_KEY`
* `AZURE_OPENAI_ENDPOINT`
* `GOOGLE_API_KEY`

and others, which are used by popular LLM providers.

### Custom variables

You can also add arbitrary key-value pairs for any other environment variables
your system requires.

### Custom CA certificates

If your organization uses custom Certificate Authority (CA) certificates for secure connections,
you can add them as environment variables using the `CUSTOM_CA_CERT_*` pattern.

To add a custom CA certificate:

1. Navigate to **Workspace settings** → **Environment variables** (or **Project settings** → **Environment variables** for project-specific certificates)
2. Add a new custom variable with a key starting with `CUSTOM_CA_CERT_`, followed by a descriptive suffix (e.g., `CUSTOM_CA_CERT_INTERNAL` or `CUSTOM_CA_CERT_CORPORATE`)
3. Paste your CA certificate content as the value (in PEM format)

These custom CA certificates will be automatically applied to:

* **Development mode**: Your custom certificates will be used when running scripts and code in the development mode commit environment
* **LLM evaluators**: The certificates will be trusted when running LLM-based tests and evaluations, ensuring secure connections to your LLM providers

<Note>
  You can add multiple custom CA certificates by creating multiple environment
  variables with different suffixes (e.g., `CUSTOM_CA_CERT_1`,
  `CUSTOM_CA_CERT_2`, etc.). All certificates matching the `CUSTOM_CA_CERT_*`
  pattern will be trusted.
</Note>

## Project-level environment variables

Project-level environment variables work the same way as workspace-level ones,
but are **specific to a single project**.
They are only used during development mode runs and LLM-based tests within that project.

To set them, navigate to **Project settings** → Select your project → **Environment variables**.

<Note>
  If an environment variable is already set at the workspace level, you will see
  a tag indicating that it is **inherited** on the project-level page. You can
  override inherited variables by setting a new value at the project level.
</Note>