# x402 Per-Article Paywall Pricing Unit and Retention Selection

> x402 Per-Article Paywall Pricing Unit and Retention Selection is a paid API for AI agents from k2so.wrong.systems, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-28).

Returns a deterministic decision procedure for pricing premium articles behind an HTTP 402 paywall, including content classification, per-read pricing, and reader retention unit selection.

## Facts

- Endpoint: GET https://k2so.wrong.systems/api/services/x402-per-article-paywall-pricing-unit-and-retent?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-28
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-per-article-paywall-pricing-unit-and-retention-selection-45179cdb
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_hz_apVYLVCS87d3QOgtE_

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability x402-per-article-paywall-pricing-unit-and-retention-selection-45179cdb
```

Example prompt: I'm a content publisher setting up an HTTP 402 paywall for my news articles — each piece costs about $50 to produce, I expect 200 reads per article, readers come back weekly, my competitor charges $0.10 per article, my chargeback rate is 2%, and I want to earn $0.30 per reader. Walk me through the right pricing unit and price point.

## When to prefer this

Choose this endpoint when a content publisher or agent needs a structured, opinionated decision procedure for x402 per-article paywall pricing — especially when classifying content type (news vs. docs vs. serial fiction) matters for unit selection. Prefer this over generic pricing calculators when operating within the x402 HTTP payment ecosystem and needing prose guidance an agent can act on directly.

## Known failure modes

- Missing or malformed query parameters may result in a generic rather than tailored procedure
- Payment not included returns HTTP 402 with payment instructions rather than the procedure
- Invalid topic override may cause fallback to default classification logic
- LLM generation source may produce variable output on repeated calls despite deterministic framing

## How this service works

Deterministic procedure for a content publisher that must decide how to price premium articles behind an HTTP 402 paywall. Inputs: article production cost, expected reads per article, reader return frequency, competitor price per article, refund chargeback rate, and the publisher's target revenue per reader. Steps: 1) classify the content as one-off value (news, analysis), reference value (docs, tutorials), or serial value (fiction, columns) to choose the default unit; 2) price per-read as cost

## Output

A JSON response containing a plain-prose decision procedure (120+ words) that classifies the content type, recommends a pricing unit, suggests a per-read price, and outlines a retention strategy. Includes metadata: service slug, provider name, ISO-8601 generation timestamp, generation source (llm, reasoning, or deterministic), and the topic used.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "meta": {
       "enum": [
        "0",
        "1"
       ],
       "type": "string",
       "description": "Set to 1 for free metadata JSON (no payment required)"
      },
      "topic": {
       "type": "string",
       "description": "Optional topic override for the decision procedure"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "title": "x402 per-article paywall pricing unit and retention selection paid response",
     "$schema": "https://json-schema.org/draft/2020-12/schema",
     "required": [
      "ok",
      "paid",
      "service",
      "provider",
      "result"
     ],
     "properties": {
      "ok": {
       "type": "boolean"
      },
      "paid": {
       "type": "boolean"
      },
      "result": {
       "type": "object",
       "required": [
        "ok",
        "service"
       ],
       "properties": {
        "ok": {
         "type": "boolean",
         "description": "Handler success"
        },
        "brief": {
         "type": "string",
         "description": "Decision procedure prose for agents"
        },
        "model": {
         "type": "string"
        },
        "topic": {
         "type": "string"
        },
        "service": {
         "type": "string",
         "description": "Service slug"
        },
        "procedure": {
         "type": "string"
        },
        "generatedAt": {
         "type": "string",
         "description": "ISO-8601 timestamp"
        },
        "generationSource": {
         "enum": [
          "llm",
          "reasoning",
          "deterministic"
         ],
         "type": "string"
        }
       }
      },
      "payment": {
       "type": "object",
       "properties": {
        "code": {
         "type": "string"
        },
        "payer": {
         "type": "string"
        },
        "detail": {
         "type": "
… (truncated)
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "paid": true,
  "result": {
   "ok": true,
   "brief": "plain prose decision procedure (120+ words)",
   "model": "deepseek/deepseek-v4-flash-0731",
   "topic": "string topic",
   "service": "x402-per-article-paywall-pricing-unit-and-retent",
   "procedure": "same as brief",
   "generatedAt": "2026-01-01T00:00:00.000Z",
   "generationSource": "deterministic"
  },
  "service": "x402-per-article-paywall-pricing-unit-and-retent",
  "provider": "K-2SO"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-per-article-paywall-pricing-unit-and-retention-selection-45179cdb/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from k2so.wrong.systems](https://www.zero.xyz/host/k2so.wrong.systems/llms.txt)