PubMed Central Open Access Subset

pmc.ncbi.nlm.nih.gov · 2 records in Data APIs, Debrid · JSON

Records 2

★ qualifiesPubMed Central Open Access Subset
Data APIsfree tieridentity anonymousno cardevidence documentedstale on 2026-12-01
★ qualifiesPubMed Central Open Access Subset (pmc-oa-opendata on S3)
Debridfree tieridentity anonymousno cardevidence measuredstale on 2026-12-01duplicate

PubMed Central Open Access Subset

Data APIs

pmc.ncbi.nlm.nih.gov/tools/pmcaws/Open access full text article corpus (public S3 bucket) with E utilities and OAI PMH APIsdata-apis/pubmed-central-open-accessJSON compare report an error

Free allowance: The PMC Article Datasets are free on AWS through an HTTPS or S3 URL with no log-in; E-utilities allow 3 requests a second per IP address without an API key and 10 a second with a free key; the OAI-PMH service allows 3 requests a second with no concurrent requests
Verdict: ★ qualifiesusable as stated; the read path was probed
Cost: free tier
Identity: anonymousno card, no phone
Binding limit: noneno named constraint binds
Evidence: documented34 sources; a first-party page was read and the sentence quoted
Freshness: stale on 2026-12-01checked 2026-10-31 (live); stale on 2026-12-01

Free tier	The PMC Article Datasets are free on AWS through an HTTPS or S3 URL with no log-in; E-utilities allow 3 requests a second per IP address without an API key and 10 a second with a free key; the OAI-PMH service allows 3 requests a second with no concurrent requests unit requests; metered on request-count; The bucket itself publishes no request or byte cap; the request limits are those of the E-utilities and OAI-PMH services. An anonymous esearch on 2026-10-30 answered x-ratelimit-limit 3.
Price	none stated
Limits	request-rate E-utilities: more than 3 requests a second per IP address without an API key answers an error; up to 10 a second by default with a key source request-rate OAI-PMH: 3 requests a second, no concurrent requests source per-object-cap ESearch: at most 10,000 returned records per query source
Binding	none The bucket publishes no request or byte cap and needs no key; the 3 a second E-utilities limit binds only on selection, which the daily inventory replaces.
Identity	anonymous No account or key for the bucket: it is read without any log-in. An E-utilities key, for 10 requests a second, comes from the Settings page of an NCBI account, which signs in through federated logins such as Login.gov, Google, Microsoft live.com, ORCiD or an institution.
Egress	Free: NLM provides the bucket through the AWS Open Data Sponsorship Program without charge, over HTTPS or S3, with no log-in. free allowance: no byte cap published
Per-object cap	one prefix per article version holding its files; ESearch returns at most 10,000 records per query, and the daily inventory CSV has no record limit
Retention	the bucket is live: a removed article version's prefix and files are deleted with no notification, detectable only by reconciling the daily inventory; inventory reports are kept 30 days; the legacy baseline packages on FTP and the Cloud Service were removed the week of August 24, 2026
Interface	s3, rest S3 bucket pmc-oa-opendata (arn:aws:s3:::pmc-oa-opendata) read with --no-sign-request, or https://pmc-oa-opendata.s3.amazonaws.com/ over HTTPS, with a daily S3 inventory CSV; E-utilities at https://eutils.ncbi.nlm.nih.gov/entrez/eutils/ (esearch with open access[filter]); OAI-PMH at https://pmc.ncbi.nlm.nih.gov/api/oai/v1/mh/; BioC API. The PMC OA Web Service is no longer available and there are no baseline bulk packages. endpoint: https://pmc-oa-opendata.s3.amazonaws.com/
Tooling	aws s3 cp or sync with --no-sign-request, or curl over HTTPS; the daily inventory CSV as the list of article versions; EDirect to page past 10,000 ESearch results
Composes with	The bucket is the bulk path: objects for roughly 8 million article versions, listed in a daily inventory CSV with no record limit; an esearch on open access[filter] counted 8357213 records on 2026-10-30; E-utilities or OAI-PMH select articles by date or licence before the S3 fetch.
Reliability	Removed article versions vanish from the bucket with no notification; exceeding the E-utilities limits can get an IP address blocked from NCBI.
Notes	The record debrid/pmc-oa-opendata describes the same bucket; this record adds the API limits and the removal of the baseline packages and the OA Web Service.
Evidence note	documented The bucket terms, the inventory and the API limits are NLM pages. An anonymous HTTPS GET of one article's full-text XML answered 200 with 109,974 bytes on 2026-10-31, and the bucket README answered 200 to an anonymous request; the E-utilities and OAI-PMH limits are documented, not measured.
Parsed numbers	has-free-tier 1 request-rate 3 requests request-rate 3 requests

Evidence 34

date	source	what it proved
2026-10-30	pmc.ncbi.nlm.nih.gov/tools/pmcaws/	the bucket is free over HTTPS or S3 with no log-in
2026-10-30	pmc.ncbi.nlm.nih.gov/tools/pmcaws/	the bucket is read anonymously with --no-sign-request
2026-10-30	pmc.ncbi.nlm.nih.gov/tools/pmcaws/	the bucket is pmc-oa-opendata
2026-10-30	pmc.ncbi.nlm.nih.gov/tools/pmcaws/	removed versions are deleted with no notification
2026-10-30	pmc.ncbi.nlm.nih.gov/tools/pmcaws/	removals show only in the inventory
2026-10-30	pmc.ncbi.nlm.nih.gov/tools/pmcaws/	the inventory is daily
2026-10-30	pmc.ncbi.nlm.nih.gov/tools/pmcaws/	ESearch returns at most 10,000 records per query
2026-10-30	pmc.ncbi.nlm.nih.gov/tools/pmcaws/	the inventory has no record limit
2026-10-30	pmc.ncbi.nlm.nih.gov/tools/pmcaws/	part of the text of Interface, above
2026-10-30	pmc.ncbi.nlm.nih.gov/tools/pmcaws/	the legacy files were removed the week of August 24, 2026
2026-10-30	pmc.ncbi.nlm.nih.gov/tools/pmcaws/	the AWS Open Data Sponsorship Program funds the access
2026-10-30	pmc.ncbi.nlm.nih.gov/tools/openftlist/	the OA subset is articles
2026-10-30	pmc.ncbi.nlm.nih.gov/tools/oa-service/	the OA Web Service is gone
2026-10-30	www.ncbi.nlm.nih.gov/books/NBK25497/	E-utilities allow 3 requests a second per IP without a key
2026-10-30	www.ncbi.nlm.nih.gov/books/NBK25497/	a key allows 10 requests a second
2026-10-30	www.ncbi.nlm.nih.gov/books/NBK25497/	the key comes from an NCBI account
2026-10-30	www.ncbi.nlm.nih.gov/books/NBK25497/	an IP address can be blocked
2026-10-30	pmc.ncbi.nlm.nih.gov/tools/oai/	OAI-PMH allows 3 requests a second
2026-10-30	pmc.ncbi.nlm.nih.gov/tools/oai/	OAI-PMH allows no concurrent requests
2026-10-30	www.ncbi.nlm.nih.gov/account/	NCBI sign-in offers Login.gov
2026-10-30	www.ncbi.nlm.nih.gov/account/	NCBI sign-in offers Microsoft live.com
2026-10-30	www.ncbi.nlm.nih.gov/account/	NCBI sign-in offers ORCiD
2026-10-30	probe: `https://pmc-oa-opendata.s3.amazonaws.com/README.txt`	the bucket holds roughly 8 million article versions
2026-10-30	probe: `https://pmc-oa-opendata.s3.amazonaws.com/README.txt`	inventory reports are kept 30 days
2026-10-30	probe: `https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esearch.fcgi?db=pmc&term=open+access%5Bfilter%5D&retmax=0&retmode=json`	esearch counted 8357213 open-access records
2026-10-30	probe: `https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esearch.fcgi?db=pmc&term=open+access%5Bfilter%5D&retmax=0&retmode=json`	an anonymous esearch was limited to 3 requests
2026-10-31	probe: `https://pmc-oa-opendata.s3.amazonaws.com/PMC10009402.1/PMC10009402.1.xml`	an anonymous GET of one full-text XML answered 200 with 109,974 bytes on 2026-10-31
2026-10-31	probe: `https://pmc-oa-opendata.s3.amazonaws.com/PMC10009402.1/PMC10009402.1.xml`	the full-text XML hashes to the sha256 the record holds
2026-10-31	pmc.ncbi.nlm.nih.gov/tools/oai/	OAI-PMH allows 3 requests a second
2026-10-31	pmc.ncbi.nlm.nih.gov/tools/pmcaws/	ESearch returns at most 10,000 records per query
2026-10-31	pmc.ncbi.nlm.nih.gov/tools/pmcaws/	the bucket is free over HTTPS or S3 with no log-in
2026-10-31	pmc.ncbi.nlm.nih.gov/tools/pmcaws/	removed versions are deleted with no notification
2026-10-31	probe: `https://pmc-oa-opendata.s3.amazonaws.com/README.txt`	the bucket holds roughly 8 million article versions
2026-10-31	www.ncbi.nlm.nih.gov/books/NBK25497/	E-utilities allow 3 requests a second per IP address without a key

More fields 2

article versions	roughly 8 million
esearch open access count 2026 10 30	8357213

PubMed Central Open Access Subset (pmc-oa-opendata on S3)

Debrid

pmc.ncbi.nlm.nih.gov/tools/pmcaws/Open access full text research corpus (world readable S3 bucket)debrid/pmc-oa-opendataJSON compare report an error

Free allowance: 'PMC makes the datasets described below freely accessible on Amazon Web Services (AWS), without charge, through either an HTTPS or S3 URL, and without any log-in requirement for retrieval.' The README reports 'roughly 8 million PMC article versions'.
Verdict: ★ qualifiesusable as stated; the read path was probed
Cost: free tier
Identity: anonymousno card, no phone
Binding limit: noneno named constraint binds
Evidence: measured16 sources; a live request was made and its output kept
Freshness: stale on 2026-12-01checked 2026-10-31 (live); stale on 2026-12-01

Free tier	'PMC makes the datasets described below freely accessible on Amazon Web Services (AWS), without charge, through either an HTTPS or S3 URL, and without any log-in requirement for retrieval.' The README reports 'roughly 8 million PMC article versions'. unit unlimited; metered on none; The bucket is s3://pmc-oa-opendata in us-east-1; the AWS Open Data Sponsorship Program covers the transfer.
Price	USD 0
Limits	request-rate no request cap is published for the S3 bucket; the article-dataset page restricts automated retrieval to the Cloud Service, OAI-PMH, E-utilities and BioC API source per-object-cap one object per article file; measured full-text XML is 109,974 bytes, so a 1 TiB pull is roughly 10 million objects The 2026-08-24 change removed the legacy FTP and cloud dataset files and left the S3 bucket as the distribution path.
Binding	none Nothing fails at 1 TiB/month: the whole corpus is smaller than that. At the measured 109,974 bytes per article version, 8 million versions is about 880 GB of XML before PDFs and media - arithmetic from the two published numbers, not a measurement of the bucket.
Identity	anonymous 'without any log-in requirement for retrieval'; an unsigned HTTPS GET for a full-text XML returned 200 here. No Earthdata-style account, no API key.
Egress	Free and unmetered: NLM pays through the AWS Open Data Sponsorship Program. 'No charges, usage fees or royalties are paid to NLM for these data.' Both https://pmc-oa-opendata.s3.amazonaws.com/<prefix>/<file> and s3:// with --no-sign-request work. free allowance: unlimited, sponsored
Per-object cap	not applicable: one object per article file (JATS XML, plain text, PDF, media). A full-text XML measured here was 109,974 bytes.
Retention	articles stay while their licence holds; 'If a version is removed from the S3 bucket, its prefix and all associated files are deleted from the bucket with no explicit notification. Inventory reconciliation is the only supported way to detect removals.' The inventory is regenerated daily and kept 30 days.
Interface	s3, rest, cli S3 REST and HTTPS on the same bucket. aws s3 cp --no-sign-request s3://pmc-oa-opendata/<PMCID>.<version>/<PMCID>.<version>.xml, or curl the equivalent https URL. S3 Inventory under inventory-reports/ gives a daily CSV manifest. endpoint: https://pmc-oa-opendata.s3.amazonaws.com/
Tooling	AWS CLI with --no-sign-request, curl, boto3 unsigned, rclone (S3 remote with anonymous access). Any of them reaches the bucket; nothing needs an account.
Composes with	The full-text corpus that pairs with Europe PMC's metadata index: harvest PMID/PMCID lists from Europe PMC or the PMC inventory, then pull the XML here.
Reliability	Removed articles vanish with no notification; the inventory lags the bucket by up to a day, so a manifest-driven sync always races deletions.
Notes	This is the strongest no-account research corpus: 8 million article versions, no login, S3 range reads, a daily inventory. The 2026-08-24 distribution change is the reason a record written before it would name FTP paths that no longer exist.
Evidence note	measured Two objects were fetched anonymously and hashed here (README.txt 14,524 bytes; one full-text XML 109,974 bytes) and the bucket's accept-ranges is byte. What is not measured is aggregate throughput at 1 and 8 connections.
Parsed numbers	has-free-tier 1 per-object-cap 1 TiB price USD 0

Evidence 16

date	source	what it proved
2026-10-23	pmc.ncbi.nlm.nih.gov/tools/pmcaws/	world-readable bucket s3://pmc-oa-opendata, 'without any log-in requirement for retrieval', --no-sign-request, and the removal-without-notification clause
2026-10-23	pmc-oa-opendata.s3.amazonaws.com/README.txt	'roughly 8 million PMC article versions' and the <PMCID>.<version>/ object layout
2026-10-23	pmc.ncbi.nlm.nih.gov/tools/cloud/	'All legacy PMC Article Dataset files on the FTP and Cloud Services were removed the week of August 24, 2026' - the bulk path changed in 2026
2026-10-23	pmc.ncbi.nlm.nih.gov/tools/openftlist/	only the Cloud Service, OAI-PMH, E-Utilities and BioC API may be used for automated retrieval of PMC content
2026-10-23	probe: `https://pmc-oa-opendata.s3.amazonaws.com/README.txt`	200, 14,524 bytes, sha256 257a001b400485176702ed49ca7607d73cd83c581bffb6dd3c9be127a2e42634, anonymous
2026-10-23	probe: `https://pmc-oa-opendata.s3.amazonaws.com/PMC10009402.1/PMC10009402.1.xml`	200, 109,974 bytes, sha256 75d9e0ab27e80e8660296e33bb1832dd8237080d5782b229bbd81fb4919c323a, accept-ranges: bytes
2026-10-31	probe: `https://pmc-oa-opendata.s3.amazonaws.com/PMC10009402.1/PMC10009402.1.xml`	the full-text XML hashes to the sha256 the record holds
2026-10-31	probe: `https://pmc-oa-opendata.s3.amazonaws.com/README.txt`	the bucket README answered 200 to an anonymous GET on 2026-10-31
2026-10-31	probe: `https://pmc-oa-opendata.s3.amazonaws.com/README.txt`	the bucket holds roughly 8 million article versions
2026-10-31	probe: `https://pmc-oa-opendata.s3.amazonaws.com/README.txt`	inventory reports are kept 30 days
2026-10-31	pmc.ncbi.nlm.nih.gov/tools/pmcaws/	the bucket is free over HTTPS or S3 with no log-in
2026-10-31	pmc.ncbi.nlm.nih.gov/tools/pmcaws/	removed versions are deleted with no notification
2026-10-31	pmc.ncbi.nlm.nih.gov/tools/pmcaws/	the legacy dataset files were removed the week of August 24, 2026
2026-10-31	pmc.ncbi.nlm.nih.gov/tools/pmcaws/	the bucket is read anonymously with --no-sign-request
2026-10-31	pmc.ncbi.nlm.nih.gov/tools/openftlist/	the subset's automated retrieval routes are the Cloud Service, OAI-PMH, E-Utilities and the BioC API
2026-10-31	probe: `https://pmc-oa-opendata.s3.amazonaws.com/PMC10009402.1/PMC10009402.1.xml`	an anonymous GET of one full-text XML answered 200 with 109,974 bytes on 2026-10-31

More fields 5

bucket	pmc-oa-opendata
region	us-east-1
article versions	8000000
xml sha256	75d9e0ab27e80e8660296e33bb1832dd8237080d5782b229bbd81fb4919c323a
estimated corpus gib	819