Wrap your API. Track usage. Collect cash. Scrawn is the open-source billing infrastructure for builders who'd rather ship features than build a payment pipeline. Drop in our SDK, define your pricing with our expression DSL, and let the backend handle the math, the webhooks, and the DodoPayments plumbing.

import { scrawn, mul } from "@scrawn/core";

const biller = scrawn({
  apiKey: process.env.SCRAWN_KEY,
  baseURL: process.env.SCRAWN_BASE_URL,
  httpUrl: process.env.SCRAWN_HTTP_URL,
});

// One line. That's it.
await biller.basicUsageEventConsumer({
  userId: "u_abc123",
  debit: biller.expr(mul(biller.tag("API_CALL"), 3)),
});

• API platforms - Charge per request, per endpoint, or per user. Define tiers with expressions like mul(tag("RATE"), inputTokens()).
• AI / LLM services - Track token consumption per model per user. Wrap any AI SDK and bill with per-model rates.
• SaaS products - Usage-based pricing for any metric: storage, bandwidth, compute time, active users.
• Developer tools - CLI tools, SDKs, and platform APIs that need metered billing without building it in-house.

Deploy → scrawn init + scrawn start spins up the stack.

Configure → Set DodoPayments keys and product ID via the onboarding wizard.

Track → Call biller.basicUsageEventConsumer({ userId, debit }) from your app.

Bill → DodoPayments handles checkout; Scrawn forwards signed webhooks and manages state.

• Pricing expression DSL - mul(tag("RATE"), inputTokens()), persisted expressions, nested references, compile-time checked tags
• AI token tracking - Wrap any AI SDK, bill per-token with granular per-model rates
• Self-hosted - Your data, your Postgres, your infrastructure, your control
• Type-safe SDK - Tags and expressions checked at compile time
• Webhook forwarding - Ed25519-signed Standard Webhooks delivered to your endpoints
• Admin dashboard - Analytics, event logs, API key management, webhook delivery history
• DodoPayments integration - Checkout links, payment collection, webhook processing
• CLI - One-command deploy, tag sync, stack management