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

# Server Configuration

> Backend environment variables, databases, Redis queues, and security parameters

<Tip>
  **Quick Setup with [`copy-env`](https://www.npmjs.com/package/copy-env)**\
  From the `backend/` directory, scaffold the runtime env file in one command:

  ```bash theme={null}
  pnpm install
  pnpm run copy-env
  ```

  This reads `copy-env-config.json` and copies `src/.env.example` to `src/.env`. The backend loads `src/.env` at startup; fill in the generated placeholders before running the server. Docker Compose can additionally load `backend/.env` when that file exists.
</Tip>

***

## Configuration Overview Table

| Feature / Setting                   | Option / Key                            | Where to Toggle                | Default Value             |
| :---------------------------------- | :-------------------------------------- | :----------------------------- | :------------------------ |
| **HTTP Listening Port**             | `PORT`                                  | `backend/src/.env` or Compose  | `5000`                    |
| **CORS Origin Allowance**           | `CLIENT_URL`                            | `backend/src/.env` or Compose  | `http://localhost:3000`   |
| **PostgreSQL Connection String**    | `DATABASE_URL`                          | `backend/src/.env` or Compose  | Required                  |
| **Redis Broker URI**                | `REDIS_URL`                             | `backend/src/.env` or Compose  | `redis://localhost:6379`  |
| **Default Fallback AI Model**       | `BASE_MODEL`                            | `backend/src/.env` or Compose  | Provider-specific         |
| **Platform AI Provider API Key**    | `AI_API_KEY`                            | `backend/src/.env` or Compose  | Unset / None              |
| **Custom AI Endpoint Gateway**      | `AI_BASE_URL`                           | `backend/src/.env` or Compose  | Provider-specific         |
| **OpenAI Client Invocation Method** | `OPEN_AI_INTERFACE`                     | `backend/src/.env` or Compose  | `chat`                    |
| **Email Delivery (Resend API)**     | `RESEND_API_KEY`                        | `backend/src/.env` or Compose  | Unset / None              |
| **GitHub Integration**              | `GITHUB_ACESSES_TOKEN`, `GITHUB_APP_*`  | `backend/src/.env` or Compose  | Unset / None              |
| **Encryption & Auth**               | `API_ENCRYPTION_KEY`, `BETTER_AUTH_URL` | `backend/src/.env` or Compose  | Unset / None              |
| **Per-User Free Spend Allowance**   | `perUserSpendLimit`                     | `backend/src/config/config.ts` | `$0.30` USD               |
| **Platform Free Model Pricing**     | `goBetterFreeModels`                    | `backend/src/config/config.ts` | Model price map           |
| **Platform InceptionLabs Gateway**  | `goBetterBaseUrl`                       | `backend/src/config/config.ts` | InceptionLabs gateway URL |

***

## Detailed Configuration Breakdown

## Where to Get Each Backend Value

Create the backend file from `backend/src/.env.example` and replace every `YOUR_VALUE_HERE` placeholder. Keep this file private: backend environment values are secrets unless marked **public configuration**.

| Variable                   |         Required         | How to acquire it                                                                                                                                |
| :------------------------- | :----------------------: | :----------------------------------------------------------------------------------------------------------------------------------------------- |
| `PORT`                     |            Yes           | Use `5000` locally. In a hosted container, use the port required by the platform and keep the Compose mapping in sync. **Public configuration.** |
| `BASE_MODEL`               |            Yes           | Copy the model ID from the AI provider's model catalog, for example `mercury-2` for InceptionLabs.                                               |
| `AI_BASE_URL`              |            Yes           | Copy the OpenAI-compatible API base URL from the provider's API documentation.                                                                   |
| `AI_API_KEY`               |            Yes           | Create an API key in the selected AI provider's dashboard. Store it only in the backend environment.                                             |
| `OPEN_AI_INTERFACE`        |            Yes           | Use `chat` for chat-completions providers. Use `responses` only when the selected provider supports it.                                          |
| `GITHUB_ACESSES_TOKEN`     |         Optional         | This is the current spelling in the template. The current backend does not read it directly; prefer the GitHub App values below.                 |
| `REDIS_URL`                |            Yes           | Create a Redis database with Redis Cloud, Upstash, Railway, or locally. Copy its full connection URI.                                            |
| `DATABASE_URL`             |            Yes           | Create a PostgreSQL database with Neon, Supabase, Railway, or locally. Copy its connection string and keep SSL parameters intact.                |
| `API_ENCRYPTION_KEY`       |            Yes           | Generate a unique 32-byte secret encoded as base64. Do not reuse a password or commit it.                                                        |
| `CLIENT_URL`               |            Yes           | Set this to the browser origin allowed to call the API, such as `http://localhost:3000` or your deployed frontend URL. **Public configuration.** |
| `API_BASE_URL`             | Yes for GitHub callbacks | Set this to the public backend origin, such as `http://localhost:5000` or `https://api.example.com`. **Public configuration.**                   |
| `BETTER_AUTH_URL`          |    Yes for hosted auth   | Set this to the backend's public origin. It normally matches `API_BASE_URL`. **Public configuration.**                                           |
| `RESEND_API_KEY`           |       Yes for email      | Create an API key in the Resend dashboard. Verify the sending domain and sender address first.                                                   |
| `GITHUB_APP_CLIENT_ID`     |   Yes for GitHub login   | Create or open a GitHub OAuth App and copy its Client ID. Set its callback URL to `<API_BASE_URL>/auth/github/callback`.                         |
| `GITHUB_APP_CLIENT_SECRET` |   Yes for GitHub login   | Copy or generate the Client secret from the same GitHub OAuth App. Store it only in the backend environment.                                     |
| `GITHUB_APP_SLUG`          | Yes for GitHub App links | Copy the slug from the GitHub App installation URL or app settings.                                                                              |

### Generate an Encryption Key

```bash theme={null}
node -e "console.log(require('crypto').randomBytes(32).toString('base64'))"
```

### Backend Secrets and Rotation

Never place `AI_API_KEY`, `DATABASE_URL`, `REDIS_URL`, `RESEND_API_KEY`, GitHub secrets, or `API_ENCRYPTION_KEY` in frontend files, source control, Docker images, or public issue reports. If a secret is exposed, revoke it at the provider immediately and replace it in the backend environment.

### 1. Networking & CORS

#### `PORT`

* **Location**: `backend/.env`
* **Description**: Defines which port the server listens on upon startup (`app.listen(port)`).
* **Example**:
  ```bash theme={null}
  PORT=5000
  ```

#### `CLIENT_URL`

* **Location**: `backend/src/.env` or the Compose environment
* **Description**: Configured in Express's `cors()` middleware in `backend/src/server.ts`:
  ```typescript theme={null}
  app.use(cors({
    origin: process.env.CLIENT_URL,
    credentials: true,
  }));
  ```
* **Example**:
  ```bash theme={null}
  CLIENT_URL=http://localhost:3000
  ```

***

### 2. Database & Storage

#### `DATABASE_URL`

* **Location**: `backend/.env`
* **Description**: Target PostgreSQL database instance. Required for running migrations via Drizzle ORM and managing client queries through `pg.Pool`.
* **Format**: `postgresql://[user]:[password]@[host]:[port]/[database]?sslmode=[mode]`
* **Example**:
  ```bash theme={null}
  DATABASE_URL=postgresql://postgres:postgres@localhost:5432/gobetter_db
  ```

#### `REDIS_URL`

* **Location**: `backend/.env`
* **Description**: Redis instance utilized for BullMQ task distribution, queueing pull request webhooks, managing user sessions, and coordinating async worker jobs.
* **Example**:
  ```bash theme={null}
  REDIS_URL=redis://localhost:6379
  ```

***

### 3. AI Engine & Provider Routing

#### `BASE_MODEL`

* **Location**: `backend/.env`
* **Description**: Default model slug invoked when a review job does not supply an explicit model preference.
* **Example**:
  ```bash theme={null}
  BASE_MODEL=openai/gpt-4o
  ```

#### `AI_API_KEY` & `AI_BASE_URL`

* **Location**: `backend/.env`
* **Description**: Supplies authentication and custom base URL for the backend's AI service (`backend/src/service/ai.service.ts`).
* **Example**:
  ```bash theme={null}
  AI_API_KEY=sk-proj-xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
  AI_BASE_URL=https://api.openai.com/v1
  ```

#### `OPEN_AI_INTERFACE`

* **Location**: `backend/.env`
* **Description**: Determines interface method on OpenAI SDK (`chat` by default).

***

### 4. Email Service & Delivery

#### `RESEND_API_KEY`

* **Location**: `backend/.env`
* **Description**: Authenticates with Resend API (`backend/src/lib/resendEmail.ts`) to dispatch transactional authentication emails (email verification OTPs, password reset links).
* **Example**:
  ```bash theme={null}
  RESEND_API_KEY=re_123456789_abcdefg
  ```

***

### 5. Platform Branding & Email Theming

Configured in `backend/.env` or defaults in `backend/src/config/config.ts`:

| Variable         | Default                                  | Purpose                                                |
| :--------------- | :--------------------------------------- | :----------------------------------------------------- |
| `BRAND_NAME`     | `Go Better`                              | Visible brand name in notification headings and emails |
| `BRAND_URL`      | `https://gobetter.dev`                   | Landing page URL linked in footers                     |
| `BRAND_TAGLINE`  | `Autonomous AI Code Reviews`             | Subtitle displayed in email headers                    |
| `FROM_EMAIL`     | `noreply@mail.gobetter.dev`              | Envelope sender address                                |
| `FROM_SENDER`    | `Go Better <noreply@mail.gobetter.dev>`  | Friendly from-name and address                         |
| `EMAIL_THEME`    | `dark`                                   | Email template theme (`dark` or `light`)               |
| `BRAND_LOGO_URL` | `https://gobetter.dev/gobetter-logo.png` | Public URL for email header badge                      |

***

### 6. In-Code Platform Pricing & Quotas

Located in [`backend/src/config/config.ts`](file:///d:/hono-rabbit/backend/src/config/config.ts):

```typescript theme={null}
// Amount user can spend on the platform before they need to enable BYOK
export const perUserSpendLimit = 0.30;

export const goBetterFreeModels = {
    'alibaba/qwen3.7-flash': {
        inputCost: 0.03,
        outputCost: 0.13
    },
    'deepseek/deepseek-v4-flash-0731': {
        inputCost: 0.05,
        outPutCost: 0.10
    },
    'nvidia/nemotron-3.5-lightning': {
        inputCost: 0.05,
        outPutCost: 0.15
    },
    'zai/glm-4.7-flashx': {
        inputCost: 0.06,
        outputCost: 0.40
    },
    'openai/gpt-oss-20b': {
        inputCost: 0.07,
        outputCost: 0.30
    },
};

export const goBetterBaseUrl = 'https://api.inceptionlabs.ai/v1/chat/completions';
```

***

## Server Environment Template (`backend/.env.example`)

```bash theme={null}
# Copy backend/src/.env.example to backend/src/.env, then replace placeholders.
PORT="YOUR_VALUE_HERE"
BASE_MODEL="YOUR_VALUE_HERE"
AI_BASE_URL="YOUR_VALUE_HERE"
AI_API_KEY="YOUR_VALUE_HERE"
OPEN_AI_INTERFACE="YOUR_VALUE_HERE"
GITHUB_ACESSES_TOKEN="YOUR_VALUE_HERE"
REDIS_URL="YOUR_VALUE_HERE"
DATABASE_URL="YOUR_VALUE_HERE"
API_ENCRYPTION_KEY="YOUR_VALUE_HERE"
CLIENT_URL="YOUR_VALUE_HERE"
API_BASE_URL="YOUR_VALUE_HERE"
BETTER_AUTH_URL="YOUR_VALUE_HERE"
RESEND_API_KEY="YOUR_VALUE_HERE"
GITHUB_APP_CLIENT_ID="YOUR_VALUE_HERE"
GITHUB_APP_CLIENT_SECRET="YOUR_VALUE_HERE"
GITHUB_APP_SLUG="YOUR_VALUE_HERE"
```