NBER Working Papers

NBER Working Papers are the pre-publication paper series of the National Bureau of Economic Research, the main circulation channel for new US economics and finance research. Both the working paper metadata (title, authors, date, abstract) and the full-text PDFs are reachable over plain HTTP with no API key. The metadata comes from an undocumented JSON listing endpoint; the PDFs sit at a predictable path keyed by the working paper number.

• Cost: free to fetch; PDFs are copyrighted (see Gotchas).
• API key: none required.
• Coverage: the full working paper series. The listing API reported 35,851 working papers as of the verification date, back to w0001.
• Home: https://www.nber.org/papers

Access

Metadata: the listing API

An undocumented JSON endpoint backs the site’s paper listing. It paginates and returns the total count plus an array of paper records:

# No key. page is 1-based; perPage caps the page size.
curl -sL "https://www.nber.org/api/v1/working_page_listing/contentType/working_paper/_/_/search?page=1&perPage=50"

Each result object carries title, authors (HTML anchor strings), displaydate (e.g. "June 2026"), abstract, and url (e.g. /papers/w35366). The working paper number is the last path segment of url, not a separate numeric field. Walk page from 1 until you have collected totalResults records.

Full text: the PDF path

Given a working paper number wNNNNN, the PDF is at a predictable path:

# No key. Returns application/pdf.
curl -sL "https://www.nber.org/system/files/working_papers/w31010/w31010.pdf" -o w31010.pdf

The human landing page for the same paper is https://www.nber.org/papers/w31010 (HTTP 200), useful for the abstract, JEL codes, and citation block.

Load metadata in Python

import requests

base = "https://www.nber.org/api/v1/working_page_listing/contentType/working_paper/_/_/search"
rows, page = [], 1
while True:
    r = requests.get(base, params={"page": page, "perPage": 100}, timeout=30).json()
    rows.extend(r["results"])
    if len(rows) >= r["totalResults"] or not r["results"]:
        break
    page += 1

# Working paper number is the tail of the url field
for x in rows[:3]:
    wp = x["url"].rsplit("/", 1)[-1]   # e.g. "w35366"
    print(wp, x["displaydate"], x["title"])

Gotchas (the ones that bite pipelines)

• The PDFs are copyrighted; fetchable is not redistributable. Free download for research use does not grant the right to rehost or bulk-redistribute the PDFs. Treat them as inputs to read and cite, not as a corpus to republish. Store locally, cite the NBER, and respect the series’ terms.
• A subset of PDFs is access-gated. Some downloads (notably very recent papers) are served free only to specific groups (subscribers, US journalists, residents of low-income countries) and otherwise sit behind a paywall. The predictable PDF path works for the open majority; do not assume every wNNNNN.pdf returns 200. Check the status code and fall back to the landing page metadata when a PDF is gated.
• The listing API is undocumented. The /api/v1/working_page_listing/... endpoint is not a published, versioned API. The path, query shape, and field names can change without notice. Pin nothing to it that you cannot quickly repair, and record the response shape with your snapshot.
• Working paper number lives in the URL, not a field. The result objects do not expose a clean numeric wpnum (it was null in testing). Parse the number from the tail of url (/papers/w35366 -> w35366).
• displaydate is a string, not a date. Dates come as "June 2026", not ISO. Parse to month resolution; do not expect a day component.
• Working papers are not peer-reviewed and are revised in place. A wNNNNN number is the working paper, which may differ from the final journal version. The PDF can be updated without a new number. Record the access date; do not treat the WP as the version of record for a published paper.
• Rate-limit your crawl. Walking 35k+ records and PDFs is a real load. Page politely, cache, and avoid hammering the host. robots.txt allows /papers/ and /system/files/ but disallows the admin and UI search paths.
• Author field is HTML. authors entries are anchor tag strings (<a href="/people/...">Name</a>), not plain names. Strip tags before use.

Reference

Field	Value
Metadata endpoint	https://www.nber.org/api/v1/working_page_listing/contentType/working_paper/_/_/search?page=N&perPage=K
PDF path	https://www.nber.org/system/files/working_papers/wNNNNN/wNNNNN.pdf
Landing page	https://www.nber.org/papers/wNNNNN
Metadata format	JSON (totalResults + results[])
Total working papers	35,851 (as of 2026-06-23)
Key required	No
PDF license	Copyrighted; free for research use, not for redistribution

Citation

Cite the individual working paper, not the series. Use the NBER’s own citation block from the landing page, for example: Author(s), “Title,” NBER Working Paper No. NNNNN, National Bureau of Economic Research, Month Year. Record the access date and note the working paper number; the PDF may be revised in place without a new number, and the final published version (if any) may differ.