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Hybrid Model

Subscriptions and Topups

Many AI platforms start with subscriptions and later add topups to handle usage spikes.

Usage spikes can dramatically increase infrastructure spend, making subscription-only models insufficient for real-world profitability. That’s why a hybrid billing model, combining stable subscriptions with usage-based topups, is becoming prevalent in the AI economy.

Credyt supports this hybrid approach even if your subscriptions are already managed externally.

  • Subscriptions remain outside Credyt - you keep using your existing PSP and billing system.
  • Credyt is informed when a subscription payment succeeds via the Adjustments API, which credits the customer’s wallet.
  • Topups for additional usage can be handled in two ways:
    • Through Credyt - using the Billing Portal or topup API (requires connecting a Stripe account).
    • Outside Credyt - process the payment with your PSP, then notify Credyt using the Adjustments API.

This lets you add real-time usage billing without rebuilding your subscription flow or changing payment providers.

Implementation guide​

Reflect Subscription Payments in Credyt​

API Reference

When a subscription renews in your PSP, call the Adjustments API to increase the wallet balance:

POST https://api.credyt.ai/customers/:customerId/wallet/adjustments
{
  "transaction_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "account_name": "default",
  "asset": "USD",
  "amount": 25,
  "description": "Monthly Subscription",
  "reason": "external_topup",
  "expires_at": "2024-07-29T15:51:28.071Z",
  "metadata": {
    "psp": "stripe",
    "payment_intent": "pi_3RjbbNJNSIruR1rb0GwMGpH0"
  }
}

Response

{
  "id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "created_at": "2024-07-29T15:51:28.071Z"
}

Wallet account balance increases by the subscription value.

Handle Topups for Additional Usage​

API Reference

Option A: Use Credyt’s Payment Rails (Stripe Checkout)

  • Customer tops up via Billing Portal (self-service) or Topup API (your UI). Read about Topups.
  • Credyt processes the payment through Stripe.
  • Requires either creating a new Stripe account or connecting your existing one via Credyt.

Option B: Keep Topups External

  • Process the payment with your PSP.
  • Call the Adjustments API to reflect the new balance in Credyt.
POST https://api.credyt.ai/customers/:customerId/wallet/adjustments
{
  "transaction_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "account_name": "default",
  "asset": "USD",
  "amount": 25,
  "description": "Ad-hoc usage",
  "reason": "external_topup",
  "expires_at": "2024-07-29T15:51:28.071Z",
  "metadata": {
    "psp": "stripe",
    "payment_intent": "pi_3RjbbNJNSIruR1rb0GwMGpH0"
  }
}

Response

{
  "id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "created_at": "2024-07-29T15:51:28.071Z"
}

Send Usage Events​

API Reference

Once the wallet is funded (from subscription or topups), usage events will deduct balances in real time:

POST https://api.credyt.ai/events
{
  "events": [
    {
      "id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "customer_id": "cust_473cr1y0ghbyc3m1yfbwvn3nxx",
      "event_type": "message_completed",
      "occurred_at": "2024-07-29T15:51:28.071Z",
      "subject": "chat_5f53d23a4958",
      "description": "Chat message completed",
      "data": {
        "model": "gpt-4-1",
        "input_tokens": 2353,
        "output_tokens": 34697
      }
    }
  ]
}