Configuration

Sunschool is highly configurable through environment variables and feature flags. This guide covers all configuration options.

Environment Variables

All configuration is managed through environment variables in the .env file.

Core Settings

DATABASE_URL

string

required

PostgreSQL connection string

DATABASE_URL="postgresql://user:password@host:port/database"

Format: postgresql://[user]:[password]@[host]:[port]/[database]Examples:

Local: postgresql://postgres:postgres@localhost:5432/sunschool
Neon: postgresql://user:pass@ep-xyz.us-east-2.aws.neon.tech/sunschool?sslmode=require
Railway: Automatically provided via $DATABASE_URL

DATABASE_SSL

boolean

default:"true"

Enable SSL for database connections

DATABASE_SSL=true

Set to false for local development without SSL.

PORT

number

default:"5000"

Port for the Express server

PORT=5000

Most hosting platforms provide $PORT automatically.

NODE_ENV

string

default:"development"

Environment mode

NODE_ENV=production

Values: development, production

Authentication

JWT_SECRET

string

required

Secret key for signing JWT tokens

JWT_SECRET="your-jwt-secret-key"

Generate securely:

openssl rand -base64 32

From server/config/env.ts:41:

export const JWT_SECRET = getEnv('JWT_SECRET', SESSION_SECRET);

JWT_EXPIRY

string

default:"7d"

JWT token expiration time

JWT_EXPIRY=7d

Format: [number][unit] where unit is s, m, h, dExamples: 30m, 12h, 7d, 90d

SESSION_SECRET

string

required

Secret key for session management

SESSION_SECRET="your-session-secret"

Generate securely:

openssl rand -base64 32

AI Provider Configuration

Sunschool supports multiple AI providers with automatic fallback chains.

OpenRouter (Primary)

OPENROUTER_API_KEY

string

required

API key for OpenRouter

OPENROUTER_API_KEY="sk-or-v1-..."

Get your key: openrouter.ai/keysFrom server/config/env.ts:48:

export const OPENROUTER_API_KEY = process.env.OPENROUTER_API_KEY || '';

Used for:

Lesson content generation
Quiz question creation
SVG illustration generation

LLM_PROVIDER

string

default:"openrouter"

Primary LLM provider

LLM_PROVIDER=openrouter

Options: openrouter, bittensor, perplexityFrom server/config/env.ts:45:

export const LLM_PROVIDER = process.env.LLM_PROVIDER || 'openrouter';

Bittensor (Experimental)

Bittensor Subnet 1 integration is experimental. OpenRouter is recommended for production.

ENABLE_BITTENSOR_SUBNET_1

boolean

default:"false"

Enable Bittensor Subnet 1 provider

ENABLE_BITTENSOR_SUBNET_1=1

From server/config/flags.ts:12:

export const ENABLE_BITTENSOR_SUBNET_1 = process.env.ENABLE_BITTENSOR_SUBNET_1 === '1';

BITTENSOR_API_KEY

string

API key for Bittensor Archive

BITTENSOR_API_KEY="your-bittensor-key"

BITTENSOR_SUBNET_1_URL

string

default:"https://archive.opentensor.ai/graphql"

GraphQL endpoint for Bittensor Subnet 1

BITTENSOR_SUBNET_1_URL="https://archive.opentensor.ai/graphql"

From server/config/env.ts:52:

export const BITTENSOR_SUBNET_1_URL = process.env.BITTENSOR_SUBNET_1_URL || 'https://archive.opentensor.ai/graphql';

BITTENSOR_WALLET_NAME

string

Bittensor wallet name for authentication

BITTENSOR_WALLET_NAME="your-wallet-name"

BITTENSOR_WALLET_HOTKEY

string

Bittensor wallet hotkey

BITTENSOR_WALLET_HOTKEY="your-hotkey"

BITTENSOR_FALLBACK_ENABLED

boolean

default:"true"

Enable automatic fallback to OpenRouter when Bittensor fails

BITTENSOR_FALLBACK_ENABLED=1

From server/config/flags.ts:13:

export const BITTENSOR_FALLBACK_ENABLED = process.env.BITTENSOR_FALLBACK_ENABLED !== '0';

Perplexity

PERPLEXITY_API_KEY

string

API key for Perplexity AI

PERPLEXITY_API_KEY="pplx-..."

Get your key: perplexity.ai/settings/apiFrom server/config/env.ts:57:

export const PERPLEXITY_API_KEY = process.env.PERPLEXITY_API_KEY || '';

Image Generation

Provider Selection

IMAGE_PROVIDER

string

default:"svg-llm"

Image generation provider

IMAGE_PROVIDER=svg-llm

Options:

svg-llm: LLM-generated SVG graphics (recommended)
openrouter: Raster images via OpenRouter
stability: Stability AI models

From server/config/env.ts:60:

export const IMAGE_PROVIDER = process.env.IMAGE_PROVIDER || 'svg-llm';

OpenRouter Image Models

OPENROUTER_IMAGE_MODEL

string

default:"google/gemini-3.1-pro-preview"

Primary model for image generation

OPENROUTER_IMAGE_MODEL="google/gemini-3.1-pro-preview"

From server/config/env.ts:61:

export const OPENROUTER_IMAGE_MODEL = process.env.OPENROUTER_IMAGE_MODEL || 'google/gemini-3.1-pro-preview';

OPENROUTER_SVG_MODEL

string

default:"google/gemini-3.1-pro-preview"

Primary model for SVG generation

OPENROUTER_SVG_MODEL="google/gemini-3.1-pro-preview"

From server/config/env.ts:62:

export const OPENROUTER_SVG_MODEL = process.env.OPENROUTER_SVG_MODEL || 'google/gemini-3.1-pro-preview';

IMAGE_MODEL_FALLBACKS

string

Comma-separated list of fallback models for image generation

IMAGE_MODEL_FALLBACKS="google/gemini-3.1-flash-image-preview,google/gemini-3-flash-preview"

Tried in order when the primary model returns 404 or fails.From server/config/env.ts:69-70:

export const IMAGE_MODEL_FALLBACKS: string[] = (process.env.IMAGE_MODEL_FALLBACKS || '')
  .split(',').map(s => s.trim()).filter(Boolean);

SVG_MODEL_FALLBACKS

string

Comma-separated list of fallback models for SVG generation

SVG_MODEL_FALLBACKS="google/gemini-3.1-flash-lite-preview,google/gemini-3-flash-preview"

From server/config/env.ts:67-68:

export const SVG_MODEL_FALLBACKS: string[] = (process.env.SVG_MODEL_FALLBACKS || '')
  .split(',').map(s => s.trim()).filter(Boolean);

Default fallbacks from server/config/env.ts:73-76:

export const DEFAULT_SVG_MODEL_FALLBACKS = [
  'google/gemini-3.1-flash-lite-preview',
  'google/gemini-3-flash-preview',
];

Image Generation Limits

IMAGE_GENERATION_TIMEOUT

number

default:"15000"

Timeout for image generation in milliseconds

IMAGE_GENERATION_TIMEOUT=15000

From server/config/env.ts:63:

export const IMAGE_GENERATION_TIMEOUT = parseInt(process.env.IMAGE_GENERATION_TIMEOUT || '15000');

MAX_IMAGES_PER_LESSON

number

default:"4"

Maximum number of images to generate per lesson

MAX_IMAGES_PER_LESSON=4

From server/config/env.ts:64:

export const MAX_IMAGES_PER_LESSON = parseInt(process.env.MAX_IMAGES_PER_LESSON || '4');

Feature Flags

Feature flags control optional functionality. See server/config/flags.ts for implementation.

AI Controls

USE_AI

boolean

default:"true"

Enable AI-generated content

USE_AI=1

Set to 0 to disable all AI features (lessons use placeholder content).From server/config/flags.ts:9:

export const USE_AI = process.env.USE_AI !== '0';

ENABLE_OPENROUTER_IMAGES

boolean

default:"true"

Enable OpenRouter image generation

ENABLE_OPENROUTER_IMAGES=1

From server/config/flags.ts:19:

export const ENABLE_OPENROUTER_IMAGES = process.env.ENABLE_OPENROUTER_IMAGES !== '0';

ENABLE_SVG_LLM

boolean

default:"true"

Enable LLM-based SVG generation

ENABLE_SVG_LLM=1

From server/config/flags.ts:20:

export const ENABLE_SVG_LLM = process.env.ENABLE_SVG_LLM !== '0';

ENABLE_STABILITY_FALLBACK

boolean

default:"false"

Enable Stability AI as fallback for image generation

ENABLE_STABILITY_FALLBACK=1

From server/config/flags.ts:21:

export const ENABLE_STABILITY_FALLBACK = process.env.ENABLE_STABILITY_FALLBACK === '1';

Analytics

ENABLE_STATS

boolean

default:"true"

Enable statistics collection

ENABLE_STATS=1

Set to 0 to disable analytics tracking (performance data, usage metrics).From server/config/flags.ts:16:

export const ENABLE_STATS = process.env.ENABLE_STATS !== '0';

Example Configurations

Minimal (Development)

# Minimal .env for local development
DATABASE_URL="postgresql://postgres:postgres@localhost:5432/sunschool"
JWT_SECRET="dev-secret-change-me"
SESSION_SECRET="dev-session-secret"
OPENROUTER_API_KEY="sk-or-v1-..."
PORT=5000

Production (Recommended)

# Production .env with all providers
DATABASE_URL="postgresql://user:pass@prod-db.example.com:5432/sunschool?sslmode=require"
DATABASE_SSL=true
JWT_SECRET="<openssl-rand-base64-32>"
JWT_EXPIRY=7d
SESSION_SECRET="<openssl-rand-base64-32>"

# AI Providers
LLM_PROVIDER=openrouter
OPENROUTER_API_KEY="sk-or-v1-..."
PERPLEXITY_API_KEY="pplx-..."

# Image Generation
IMAGE_PROVIDER=svg-llm
OPENROUTER_SVG_MODEL="google/gemini-3.1-pro-preview"
SVG_MODEL_FALLBACKS="google/gemini-3.1-flash-lite-preview,google/gemini-3-flash-preview"
IMAGE_GENERATION_TIMEOUT=15000
MAX_IMAGES_PER_LESSON=4

# Feature Flags
USE_AI=1
ENABLE_STATS=1
ENABLE_SVG_LLM=1
ENABLE_OPENROUTER_IMAGES=1

# Server
PORT=5000
NODE_ENV=production

Bittensor Experimental

# Bittensor-first configuration with OpenRouter fallback
DATABASE_URL="postgresql://user:pass@host:5432/sunschool"
JWT_SECRET="<secure-key>"
SESSION_SECRET="<secure-key>"

# Bittensor Primary
LLM_PROVIDER=bittensor
ENABLE_BITTENSOR_SUBNET_1=1
BITTENSOR_API_KEY="your-key"
BITTENSOR_SUBNET_1_URL="https://archive.opentensor.ai/graphql"
BITTENSOR_WALLET_NAME="wallet"
BITTENSOR_WALLET_HOTKEY="hotkey"

# OpenRouter Fallback
BITTENSOR_FALLBACK_ENABLED=1
OPENROUTER_API_KEY="sk-or-v1-..."

# Feature Flags
USE_AI=1
ENABLE_STATS=1

Advanced Configuration

Database Connection Pooling

Sunschool uses pg with Neon serverless driver. Connection pooling is handled automatically. For high-traffic deployments, configure external pooling (e.g., PgBouncer):

DATABASE_URL="postgresql://user:pass@pgbouncer:6432/sunschool?sslmode=require"

CORS Configuration

CORS is enabled by default for all origins in development. For production, edit server/index.ts:

import cors from 'cors';

app.use(cors({
  origin: 'https://yourdomain.com',
  credentials: true,
}));

Rate Limiting

Sunschool does not include built-in rate limiting. Use a reverse proxy (nginx, Caddy) or middleware:

npm install express-rate-limit

import rateLimit from 'express-rate-limit';

const limiter = rateLimit({
  windowMs: 15 * 60 * 1000, // 15 minutes
  max: 100, // limit each IP to 100 requests per windowMs
});

app.use('/api/', limiter);

Configuration Validation

Sunschool validates critical environment variables on startup. Missing required variables throw errors:

// From server/config/env.ts:20-28
export function getEnv(key: string, fallback?: string): string {
  const value = process.env[key];
  if (value === undefined) {
    if (fallback !== undefined) {
      return fallback;
    }
    throw new Error(`Environment variable ${key} is required but not set`);
  }
  return value;
}

Startup Checks

When the server starts:

Database connection is tested
Migrations are run automatically
Missing API keys log warnings (not errors) for optional providers

Next Steps

First Steps

Navigate the interface and manage learners

Installation

Self-host Sunschool on your infrastructure

API Reference

Integrate with the Sunschool API

Quickstart

Complete walkthrough from signup to first lesson

Troubleshooting

API key not working

Symptoms: Failed to generate lesson content, 401 errorsSolutions:

Verify the API key is correct (no extra spaces or quotes)
Check the provider’s dashboard for key status
Test the key with a curl request
Ensure the account has sufficient credits/quota

Feature flag not taking effect

Symptoms: Feature still enabled/disabled after changing flagSolutions:

Restart the server: npm start
Check .env file has no typos in variable names
Verify the flag is read correctly: add console.log(USE_AI) in server/config/flags.ts
Clear any cached environment variables

Image generation is slow

Symptoms: Lessons load but images take 20+ secondsSolutions:

Increase IMAGE_GENERATION_TIMEOUT (default: 15000ms)
Use faster models in fallback chain (e.g., gemini-3-flash-preview)
Reduce MAX_IMAGES_PER_LESSON to 2-3
Check OpenRouter model availability at openrouter.ai/models

Database SSL error

Symptoms: Error: self signed certificate, SSL SYSCALL errorSolutions:

For local dev, set DATABASE_SSL=false
For production, ensure the database supports SSL
Add ?sslmode=require to DATABASE_URL
Check the database provider’s SSL documentation

Introduction

Setup

Configuration

Configuration

Environment Variables

Core Settings

Authentication

AI Provider Configuration

OpenRouter (Primary)

Bittensor (Experimental)

Perplexity

Image Generation

Provider Selection

OpenRouter Image Models

Image Generation Limits

Feature Flags

AI Controls

Analytics

Example Configurations

Minimal (Development)

Production (Recommended)

Bittensor Experimental

Advanced Configuration

Database Connection Pooling

CORS Configuration

Rate Limiting

Configuration Validation

Startup Checks

Next Steps

First Steps

Installation

API Reference

Quickstart

Troubleshooting

Introduction

Setup

​Configuration

​Environment Variables

​Core Settings

​Authentication

​AI Provider Configuration

​OpenRouter (Primary)

​Bittensor (Experimental)

​Perplexity

​Image Generation

​Provider Selection

​OpenRouter Image Models

​Image Generation Limits

​Feature Flags

​AI Controls

​Analytics

​Example Configurations

​Minimal (Development)

​Production (Recommended)

​Bittensor Experimental

​Advanced Configuration

​Database Connection Pooling

​CORS Configuration

​Rate Limiting

​Configuration Validation

​Startup Checks

​Next Steps

First Steps

Installation

API Reference

Quickstart

​Troubleshooting

Configuration

Environment Variables

Core Settings

Authentication

AI Provider Configuration

OpenRouter (Primary)

Bittensor (Experimental)

Perplexity

Image Generation

Provider Selection

OpenRouter Image Models

Image Generation Limits

Feature Flags

AI Controls

Analytics

Example Configurations

Minimal (Development)

Production (Recommended)

Bittensor Experimental

Advanced Configuration

Database Connection Pooling

CORS Configuration

Rate Limiting

Configuration Validation

Startup Checks

Next Steps

Troubleshooting