Research Papers Search: OpenAlex, Crossref, Europe PMC

Search academic research papers in three open scholarly databases with one query. The Actor merges results by DOI, so you get one row per paper. Each row has the title, authors, year, journal, citation counts and an open access link when one exists. It is built for AI agents, literature reviews and research tools.

What it covers

Source	Coverage	What it adds
OpenAlex	All fields of research	Venue, open access status and link, citation count
Crossref	DOI records from most journals, books and conferences	Publisher record, citation count, licence
Europe PMC	Life sciences and medicine, including PubMed and preprints	PubMed and PubMed Central IDs, citation count

One search reads up to the "Maximum papers" number from each source. A typical search with 25 papers finishes in a few seconds.

What you get

Field	Meaning
title	Paper title
authors	Author names as published in the scholarly record, up to 50
authorCount	Number of authors
year, publicationDate	Publication year and date
venue, publisher	Journal, book or preprint server, and the publisher
type	Work type as the source labels it
doi, url	DOI and DOI link
abstractSnippet	First 600 characters of the abstract, only under an open licence (see below)
license	Creative Commons licence of the paper, when a source reports one
isOpenAccess, openAccessUrl	Open access status and a link to the free full text
citationCount	Highest citation count from any source
citationCounts	Citation count from each source
sources	Sources that returned the paper
openalexId, pmid, pmcid, europepmcId	IDs in each database
rank	Position in the merged list

Sample record from a test run (query metformin gestational diabetes, 2020 to 2024, open access only):

{
    "id": "doi:10.1007/s00125-024-06252-y",
    "doi": "10.1007/s00125-024-06252-y",
    "title": "Metformin and small for gestational age babies: findings of a randomised placebo-controlled clinical trial of metformin in gestational diabetes (EMERGE)",
    "authors": [
        "Fidelma Dunne",
        "Christine Newman",
        "Alberto Alvarez‐Iglesias",
        "Paula Mary O’Shea",
        "Declan Devane",
        "Paddy Gillespie",
        "Aoife Maria Egan",
        "Martin James O'Donnell",
        "Andrew Smyth"
    ],
    "authorCount": 9,
    "year": 2024,
    "publicationDate": "2024-08-31",
    "venue": "Diabetologia",
    "publisher": "Springer Science+Business Media",
    "type": "article",
    "abstractSnippet": "AIMS/HYPOTHESIS: Gestational diabetes mellitus (GDM) is associated with adverse perinatal outcomes because of suboptimal glucose management and glucose control and excessive weight gain. Metformin can offset these factors but is associated with small for gestational age (SGA) infants. We sought to identify risk factors for SGA infants, including the effect of metformin exposure on SGA status. METHODS: In this prespecified secondary analysis of the EMERGE trial, which evaluated the effectiveness of metformin vs placebo in treating GDM and found reduced gestational weight gain and longer time...",
    "license": "cc-by",
    "isOpenAccess": true,
    "openAccessUrl": "https://link.springer.com/content/pdf/10.1007/s00125-024-06252-y.pdf",
    "url": "https://doi.org/10.1007/s00125-024-06252-y",
    "citationCount": 10,
    "citationCounts": {
        "openalex": 10,
        "crossref": 9,
        "europepmc": 7
    },
    "sources": [
        "openalex",
        "crossref",
        "europepmc"
    ],
    "openalexId": "W4402078045",
    "pmid": "39215812",
    "pmcid": "PMC11604746",
    "europepmcId": "MED/39215812",
    "rank": 2,
    "query": "metformin gestational diabetes",
    "scrapedAt": "2026-10-21T11:44:01.339Z"
}

Some fields can be empty:

• abstractSnippet is empty unless the paper is under CC0, CC BY or CC BY-SA. Abstracts under other licences can be under publisher copyright, so the Actor leaves them out.
• doi is empty for some Europe PMC records, such as Agricola entries. Those rows use the Europe PMC link in url.
• isOpenAccess is null when no source states the status.
• pmid and pmcid are empty for papers outside PubMed.

How to use it

1. Enter a search query, for example urban heat island mitigation.
2. Optional: pick sources, a year range, or open access only.
3. Set the maximum number of papers. The default is 25.
4. Run the Actor. Read the results as JSON, CSV or Excel, or call it from an AI agent through the Apify API or MCP server.

Input

Option	Default	Meaning
Search query	Sample query	Words to search for
DOIs to look up	None	Look up known papers by DOI instead of searching. One row per DOI found, in your order
Sources	All three	OpenAlex, Crossref, Europe PMC
From year, To year	None	Publication year range
Open access only	Off	Keep only papers a source marks as open access
Sort by	Relevance	Relevance, newest first or most cited first
Paper types	All	Keep only journal articles, preprints, reviews, book chapters or datasets. Others are skipped free
Maximum papers	25	Papers to save. 0 reads up to 1,000 records per source
OpenAlex API key	None	Optional free key. See below

OpenAlex key

OpenAlex works without a key, but the keyless budget is small and shared by everyone on the same IP address. If that budget runs out, the run logs a warning, skips OpenAlex and returns results from the other sources. For steady use, get a free key at openalex.org/settings/api and paste it in the input. The key is stored as a secret.

Look up papers by DOI

Paste a reference list into DOIs to look up to get the metadata, citation counts, licence and open access link for each paper:

{
    "dois": ["10.1038/nature12373", "https://doi.org/10.1126/science.1259855"]
}

The Actor asks OpenAlex and Crossref for each DOI and merges the answers. A DOI that neither source knows is named in the log and costs nothing.

Pricing

You pay a small fee per run start and a fee per paper saved. Duplicates across sources are merged before saving, so each paper is charged once. See the Pricing tab for the current prices.

Data sources and use

• The Actor uses the official public APIs of OpenAlex, Crossref and Europe PMC. It needs no login.
• It identifies itself to each API with a contact address, as Crossref and OpenAlex ask.
• It sends a few requests per run and reads at most 1,000 records per source.
• It collects no email addresses, affiliations or other contact details. Author names come from the published record.
• OpenAlex data is CC0. Crossref states that almost none of its metadata is subject to copyright. Europe PMC is run by EMBL-EBI and asks users to respect the rights of the original data owners. Credit the sources and the paper authors when you publish results.
• arXiv and ClinicalTrials.gov are not included. Their robots.txt files disallow the API paths for automated clients.

Support

Open an issue on the Issues tab. Include the run ID and the input you used.