Bring Your Own Key (BYOK)

Use your own LLM provider API keys with X-Engine for direct billing, custom rate limits, and full cost control.

How BYOK Works

When you register your own API key, X-Engine uses it for provider calls instead of the platform key. You pay the provider directly, X-Engine charges only for infrastructure (routing, caching, memory, telemetry).

Your App → X-Engine (routing + intelligence) → Provider (your API key)
                                                    ↓
                                            Billed to YOUR account

Setup

1. Register a BYOK Provider

curl -X POST https://api.xantly.com/v1/byok/providers \
  -H "Authorization: Bearer $XANTLY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "provider": "openai",
    "api_key": "sk-your-openai-key",
    "is_active": true,
    "priority": 1
  }'

Supported providers: openai, anthropic, groq, deepseek, nvidia, google.

2. Make Requests as Usual

No changes needed, X-Engine automatically detects and uses your BYOK key:

curl -X POST https://api.xantly.com/v1/chat/completions \
  -H "Authorization: Bearer $XANTLY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "openai/gpt-4o",
    "messages": [{"role": "user", "content": "Hello"}]
  }'

3. Check Which Key Was Used

Every response includes a cost_attribution field:

{
  "xantly_metadata": {
    "cost_attribution": "byok",
    "provider_used": "openai",
    "cost_usd": 0.0023
  }
}

• "cost_attribution": "byok", your key was used, you pay the provider directly
• "cost_attribution": "xantly", platform key was used, billed through X-Engine

Multiple Providers

Register keys for multiple providers to enable intelligent routing across your own accounts:

# Register OpenAI key
curl -X POST https://api.xantly.com/v1/byok/providers \
  -H "Authorization: Bearer $XANTLY_API_KEY" \
  -d '{"provider": "openai", "api_key": "sk-...", "priority": 1}'

# Register Anthropic key
curl -X POST https://api.xantly.com/v1/byok/providers \
  -H "Authorization: Bearer $XANTLY_API_KEY" \
  -d '{"provider": "anthropic", "api_key": "sk-ant-...", "priority": 2}'

X-Engine's BaRP router selects the optimal model across ALL your registered providers, respecting priority order for cost-equivalent options.

BYOK + Audio/Images/Moderations

BYOK keys also apply to proxy endpoints:

If no BYOK key is registered for OpenAI, the platform key is used as fallback.

Security

• API keys are encrypted at rest (AES-256-GCM)
• Keys are never logged or exposed in responses
• Keys are never visible after creation, only the provider and status are returned
• Rotate keys anytime via PUT /v1/byok/providers/:id

Cost Savings

With BYOK, you get:

• Direct provider pricing: no markup on token costs
• Volume discounts: your provider tier applies
• Full cost visibility: see exact costs in Mission Control
• Caching savings: X-Engine's semantic cache reduces calls regardless of key source