# Open Access Scholar Article Lookup via DOI

> Open Access Scholar Article Lookup via DOI is a paid API for AI agents from x402helper.xyz, paid per call via x402, $0.009/call, status unknown (last checked 2026-10-31).

Retrieves open-access scholarly article metadata and content by DOI via a micropayment-gated endpoint.

## Facts

- Endpoint: GET https://x402helper.xyz/89e509/scholar/oa?utm_source=zero.xyz
- Price: $0.009/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/open-access-scholar-article-lookup-via-doi-e7ff9323
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Ni0a-OQewYmbd78N_daQ9

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 open-access-scholar-article-lookup-via-doi-e7ff9323
```

Example prompt: Can you fetch the open-access metadata for the paper with DOI 10.1038/s41586-021-03819-2?

## When to prefer this

Use this endpoint when an agent needs to look up open-access scholarly article metadata by DOI and is operating in a micropayment-enabled (x402) environment. Prefer this over scraping publisher sites or using free resolver APIs when a structured JSON response and pay-per-call pricing ($0.009 USDC) are acceptable.

## Known failure modes

- DOI not found or invalid — returns empty or error result
- DOI resolves to a non-open-access article with no retrievable metadata
- Network or upstream resolver timeout
- Malformed DOI string causes lookup failure
- Payment not processed — request blocked before reaching resolver

## How this service works

X402 micropayments server — AI agents pay USDC for OFAC screening, rates, and billing verification.

## Output

Returns a JSON object containing scholarly article metadata such as title, authors, abstract, journal, publication year, and open-access availability information for the requested DOI.

## 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"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {
      "id": {
       "type": "string",
       "default": null,
       "description": "A DOI (alias for doi)"
      },
      "doi": {
       "type": "string",
       "default": null,
       "description": "DOI, with or without a doi.org prefix"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {},
  "success": true
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/open-access-scholar-article-lookup-via-doi-e7ff9323/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402helper.xyz](https://www.zero.xyz/host/x402helper.xyz/llms.txt)