---
title: "Environment Variables"
description: "Presenton can be customized and secured using environment variables. These variables control access, integrations, and model providers."
---

### 🔧 Core Configuration

* **`CAN_CHANGE_KEYS`**
  Controls whether users can view or modify API keys via the interface.
  Set to `"false"` to keep keys hidden and locked, or `"true"` to allow modification.
  *Example:*

  ```bash
  CAN_CHANGE_KEYS="false"
  ```

* **`LLM`**
  Select the Large Language Model (LLM) provider to use.
  Supported values: `"openai"`, `"google"`, `"ollama"`, `"custom"`
  *Example:*

  ```bash
  LLM="openai"
  ```

### 🧠 Model Provider Specific Variables

#### 🔹 OpenAI

* **`OPENAI_API_KEY`**
  Required if `LLM="openai"`
  *Example:*

  ```bash
  OPENAI_API_KEY="sk-xxxxxxxxxxxxxxxx"
  ```

#### 🔹 Google

* **`GOOGLE_API_KEY`**
  Required if `LLM="google"`
  *Example:*

  ```bash
  GOOGLE_API_KEY="AIzaSyXXXXXXXXXXXX"
  ```
  > ⚠️ Image generation is not supported in EU regions with Google.

#### 🔹 Ollama

* **`OLLAMA_URL`**
  (Optional) URL of your custom Ollama server. Useful if you're self-hosting.
  *Example:*

  ```bash
  OLLAMA_URL="http://localhost:11434"
  ```

* **`OLLAMA_MODEL`**
  Required if `LLM="ollama"`
  *Example:*

  ```bash
  OLLAMA_MODEL="llama3.2:3b"
  ```

#### 🔹 Custom (OpenAI-compatible LLMs)

* **`CUSTOM_LLM_URL`**
  Required if `LLM="custom"`
  *Example:*

  ```bash
  CUSTOM_LLM_URL="https://api.your-custom-llm.com/v1"
  ```

* **`CUSTOM_LLM_API_KEY`**
  Required if `LLM="custom"`
  *Example:*

  ```bash
  CUSTOM_LLM_API_KEY="your_custom_key"
  ```

* **`CUSTOM_MODEL`**
  Required if `LLM="custom"`
  *Example:*

  ```bash
  CUSTOM_MODEL="llama3.2:3b"
  ```

### 🖼️ Image Enhancement

* **`PEXELS_API_KEY`**
  (Optional) Used to fetch high-quality stock images when using `ollama` or `custom` models.
  *Example:*

  ```bash
  PEXELS_API_KEY="vzXXXXXXXXXXXXXX"
  ```

### 🐳 Docker Example

```bash
docker run -it --name presenton -p 5000:80 \
  -e LLM="ollama" \
  -e OLLAMA_MODEL="llama3.2:3b" \
  -e OLLAMA_URL="http://localhost:11434" \
  -e CAN_CHANGE_KEYS="false" \
  -e PEXELS_API_KEY="your_pexels_key" \
  -v "./user_data:/app/user_data" \
  ghcr.io/presenton/presenton:latest
```