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1. What is Paywalls.ai?

Paywalls.ai is a programmable paywall and usage-based billing proxy for OpenAI-compatible APIs.
It lets you monetize any LLM without changing your frontend code — simply route your API requests through Paywalls.ai instead of calling the model provider directly.
OpenAPI spec: https://api.paywalls.ai/v1/openapi.yml

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2. Create Your Account & API Key

  1. Sign up at Paywalls.ai Dashboard
  2. Create a Paywall in the dashboard
  3. Copy your API Key (you’ll use this in the Authorization header)

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3. Point Your App to the Proxy

Replace your OpenAI endpoint and key with the Paywalls.ai endpoint and your API key. **Example (Node.js with **openainpm package): 
import OpenAI from "openai";

const client = new OpenAI({
  apiKey: "sk-paywalls-xxxxxxxx",
  baseURL: "https://api.paywalls.ai/v1",
});

const completion = await client.chat.completions.create({
  model: "gpt-3.5-turbo",
  messages: [{ role: "user", content: "Hello world" }],
  user: "user_123", // or pass via X-Paywall-User header
});

console.log(completion.choices[0].message.content);
Note: You can pass the user ID in the request body (user property) or in an X-Paywall-User header. Learn more about User Identification.

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4. How It Works (In Short)

  1. Proxy receives your request
    Identifies the user and checks their paywall authorization and balance.
  2. If not authorized → returns an authorization link
    If balance too low → returns a topup link
  3. If authorized → forwards the request to the LLM provider
  4. Bills in real time based on actual usage (tokens, per-request fees, or both)

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5. Billing Options

You can configure each paywall or model to bill by:
  • Per request — fixed price per API call
  • Per token — based on measured prompt & completion tokens
  • Manual charges — via /user/charge
  • Subscriptions — handled externally or via custom logic

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6. Benefits

  • Drop-in compatible with the OpenAI API
  • No custom billing or metering code required
  • Works with any frontend/backend stack
  • Supports pay-per-message, microtransactions, and token quotas
  • Use with code or no-code tools (Zapier, n8n, Flowise, etc.)