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Building an AI application often requires a hybrid billing model: you want to charge a flat subscription fee that includes a base allowance of AI credits, and then seamlessly charge users for any usage that exceeds that allowance. Blink natively supports this model by combining Subscription Products, Metered Credits Deliverables, and our Usage Records API. This guide walks you through the entire lifecycle.

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1. Create the Product and Configure Overage Pricing

The foundation of your billing model is the Product. Here, you define the flat subscription fee (e.g., 20/month)andtheoveragerate(e.g.,20/month) and the overage rate (e.g., 0.005 per credit). When creating your product (via the dashboard or the API), ensure you set:
  • Pricing Model: subscription
  • Subscription Interval: month (or your preferred cycle)
  • Metered Pricing: Enable metered pricing (has_metered: true in the API) and define your metered_prices tiers. This explicitly sets the overage rate that Stripe will use when the user exhausts their base allowance.
Sub-cent Pricing (e.g., 0.005pertoken)∗∗BecausetheAPIacceptspricesinintegercents(‘unitamount‘),youcannotdirectlyspecify0.005 per token)** Because the API accepts prices in integer cents (`unit_amount`), you cannot directly specify 0.005 (which is half a cent). Instead, you must package your credits into blocks. For example, to charge 0.005percredit,priceitas∗∗0.005 per credit, price it as **5.00 per 1,000 credits by setting unit_amount: 500 and configuring a transform_quantity block to divide usage by 1,000.

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2. Issue the Base Allowance (Metered Credits Deliverable)

Now that you have a subscription product that can bill for overages, you need to grant the customer their base allowance (e.g., 10,000 AI tokens) every billing cycle. You do this by attaching a Metered Credits Deliverable to your Product in the dashboard:
  1. Navigate to Deliverables in your Blink dashboard.
  2. Add a new Metered Credits deliverable.
  3. Set the grant amount (e.g., 10,000).
  4. Select whether unused credits should roll over to the next billing cycle.
  5. Attach this deliverable to your Product.
When a customer subscribes, Blink automatically provisions a Meter and grants them the specified credits. This grant resets (and potentially rolls over) automatically upon every subscription renewal.

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3. Provision Access (API Keys)

If your app requires developers or users to authenticate programmatically, you can attach an API Keys Deliverable to the same product. Blink will automatically generate secure API keys for the customer. Furthermore, if you configure the deliverable to Revoke access on subscription end, Blink will auto-lock the API keys if the subscription is canceled or fails to renew, instantly gating access.

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4. Report Consumption

As the customer uses your AI application, you report their consumption to Blink using the Usage Records API. When you POST /v1/usage-records with the consumed quantity:
  • Blink decrements the customer’s base allowance (the meter balance).
  • Behind the scenes, Blink pushes the exact consumption event to Stripe’s v2 Meter Events API.

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How Overage is Handled

You do not need to write custom logic to detect when the balance hits zero.
  1. You simply report all usage unconditionally to the POST /v1/usage-records endpoint.
  2. Blink synchronizes the usage to Stripe.
  3. At the end of the billing cycle, Stripe automatically subtracts the base allowance (granted by the deliverable) from the total reported usage.
  4. If the usage exceeds the allowance, Stripe automatically invoices the customer for the difference using the Overage Pricing you configured on the Product in Step 1.
Because overages are calculated by Stripe asynchronously at the end of the billing cycle, the POST /v1/usage-records endpoint does not synchronously return a “new balance” or “overage incurred” payload. Rely on the invoice webhooks for final billing amounts.