# Swartzpath — Legal Open-Access Paper Resolver

> Swartzpath — Legal Open-Access Paper Resolver is a paid API for AI agents from api.robotsshop.io, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).

Resolves a paper DOI or title to a legal open-access PDF URL via Unpaywall/OpenAlex, returning nothing for paywalled papers

## Facts

- Endpoint: GET https://api.robotsshop.io/v0/swartzpath
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/swartzpath-legal-open-access-paper-resolver-83cbb1c7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_v-tw4lv66NSP2UxlAO60C

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 swartzpath-legal-open-access-paper-resolver-83cbb1c7
```

Example prompt: Can you find a legal free PDF for the paper with DOI 10.1038/nature12373? I want the open-access version if it exists, not Sci-Hub.

## When to prefer this

Choose this endpoint when you need to find a legally free PDF for a specific academic paper and want to stay within copyright law. Prefer it over general web search when you have a DOI or paper title and need a direct, machine-readable OA URL from authoritative academic open-access databases. Not suitable for paywalled-only papers or gray-market sources.

## Known failure modes

- Paper has no legal open-access version — closed access papers return no URL
- Invalid or malformed DOI results in resolution failure
- Free-text search query is ambiguous and matches wrong paper
- Paper not yet indexed by Unpaywall or OpenAlex
- Rate limiting or upstream provider unavailability

## How this service works

Swartzpath — legal OA path to the paper (Unpaywall/OpenAlex). Not Sci-Hub. Closed stays closed.

## Output

Returns the legal open-access PDF URL for the paper if one exists via Unpaywall or OpenAlex repositories; if the paper is paywalled with no legal OA version, the response indicates closed access. Does not return Sci-Hub or piracy links.

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "doi": "10.1038/nature12373",
  "grade": "A",
  "seller": "RobotsShop",
  "pdf_url": "https://example.org/paper.pdf",
  "product": "Swartzpath",
  "oa_status": "gold"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/swartzpath-legal-open-access-paper-resolver-83cbb1c7/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.robotsshop.io](https://www.zero.xyz/host/api.robotsshop.io/llms.txt)