Academic paper search API: titles, authors, citations and DOI

$0.01 per call · failed calls are never charged · no account or subscription: pay per call with a card key or USDC

Research papers search across journals, conferences, preprints and books (Crossref): title, authors, year, venue, citation count, DOI link and abstract where available. Optional fromYear filter and up to 20 results per call. Use for research agents, literature reviews, fact-checking a claim against published work, and finding the DOI for a citation.

When to use it

Run it free (25 free calls) Buy credits by card (from $1) Example result (JSON)

Try it with your own inputs

Search terms, a title or a research question (3-300 characters)

Uses one of your 25 free calls. Nothing is charged, and a call that fails is not counted.

Inputs

NameTypeDescription
query (required)stringSearch terms, a title or a research question (3-300 characters)
limitintegerNumber of results, 1-20 (default 5)
fromYearintegerOnly works published in or after this year

Request

Over HTTP, with a card key from /credits:

curl -H "Authorization: Bearer adt_…" "https://tools.funwords.eu/papers?query=CRISPR%20off-target%20effects"

Or one of your 25 free calls, no key:

curl "https://tools.funwords.eu/papers?query=CRISPR%20off-target%20effects&trial=1"

Without a key, the same URL answers 402 Payment Required with x402 and MPP terms, so an agent with a wallet pays per call in USDC (Base, Polygon, Arbitrum or Solana over x402; Base or Tempo over MPP) and retries.

Example result

{
  "query": "CRISPR off-target effects",
  "totalMatches": 819818,
  "returned": 1,
  "results": [
    {
      "title": "Off-target effects in CRISPR/Cas9 gene editing",
      "authors": [
        "Congting Guo",
        "Xiaoteng Ma"
      ],
      "year": 2023,
      "venue": "Frontiers in Bioengineering and Biotechnology",
      "type": "journal-article",
      "citations": 632,
      "doi": "10.3389/fbioe.2023.1143157",
      "url": "https://doi.org/10.3389/fbioe.2023.1143157"
    }
  ]
}

From an AI agent (MCP)

Add the MCP server to Claude, Cursor or any MCP client. This tool is papers, and the first 25 successful calls are free:

https://tools.funwords.eu/mcp

Questions

How many results?

Up to 20 per call (default 5), optionally only works from fromYear onwards.

What does each result include?

Title, authors, year, venue, citation count, DOI link and abstract where available.

How do I pay?

Each successful call costs $0.01; failed calls are not charged. The first 25 calls are free. Then pay with card credits (from $1; the key goes in an Authorization header or, for clients that can only fetch a URL, as api_key= in the URL) or per call in USDC over x402 or MPP. No account is needed.

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