The crawl archive for September 2016 is now available! The archive located in the commoncrawl bucket at crawl-data/CC-MAIN-2016-40/ contains more than 1.72 billion web pages.
To extend the seed list, we mined sitemaps from the robots.txt dataset and sorted the list of sitemap URLs based on host-level page ranks from Common Search. The highest-ranked 150,000 sitemaps were added to the crawl seed list. For the majority of sitemaps, a maximum of 5,000 potential new URLs per-sitemap were allowed. For the top 5,000 hosts/sitemaps, up to 200,000 potential new URLs were allowed. As a result, the September crawl archive contains 150 million previously unknown URLs. We plan to extend this approach in depth (allowing more URLs per sitemap) and breadth (adding sitemaps from more hosts), provided that it does not impact the quality of crawled content in terms of duplicates and/or spam.
To assist with exploring and using the dataset, we provide gzipped files that list:
- all segments (CC-MAIN-2016-40/segment.paths.gz)
- all WARC files (CC-MAIN-2016-40/warc.paths.gz)
- all WAT files (CC-MAIN-2016-40/wat.paths.gz)
- all WET files (CC-MAIN-2016-40/wet.paths.gz)
By simply adding either s3://commoncrawl/ or https://data.commoncrawl.org/ to each line, you end up with the S3 and HTTP paths respectively.
The Common Crawl URL Index for this crawl is available at: https://index.commoncrawl.org/CC-MAIN-2016-40/.
For more information on working with the URL index, please refer to the previous blog post or the Index Server API. There is also a command-line tool client for common use cases of the URL index.
WARC archives containing containing robots.txt files and responses without content (404s, redirects, etc.) are also provided:
- robots.txt files (CC-MAIN-2016-40/robotstxt.paths.gz)
- non-200 HTTP status code responses (CC-MAIN-2016-40/non200responses.paths.gz)
Please donate to Common Crawl if you appreciate our free datasets! We’re also seeking corporate sponsors to partner with Common Crawl for our non-profit work in open data. Please contact info@commoncrawl.org for sponsorship information and packages.
Erratum:
Content is truncated
Some archived content is truncated due to fetch size limits imposed during crawling. This is necessary to handle infinite or exceptionally large data streams (e.g., radio streams). Prior to March 2025 (CC-MAIN-2025-13), the truncation threshold was 1 MiB. From the March 2025 crawl onwards, this limit has been increased to 5 MiB.
For more details, see our truncation analysis notebook.
Erratum:
No truncation indicator in WARC records
Due to an issue with our crawler, not all truncations were indicated correctly. A workaround to detect length truncation is to be suspicious if the length of the content is exactly 1048576 bytes. Truncations for time or network do not have such a workaround. In the WARC files this indicator is called "WARC-Truncated".
Erratum:
Missing content_truncated flag in URL indexes
The flag in our URL indexes (CDX and columnar) that indicates whether or not a WARC record payload was truncated was added in CC-MAIN-2019-47. This indicator is missing in our indexes for all previous crawl releases. In the CDX index this is referred to as "truncated", and the columnar index refers to this as "content_truncated".
For more information please refer to the blog post announcing the November 2019 crawl. The reason for the truncation is given only for truncated records following the WARC header field "WARC-Truncated".
Erratum:
WAT data: repeated WARC and HTTP headers are not preserved
Repeated HTTP and WARC headers were not represented in the JSON data in WAT files. When a header was repeated adding a further value of that header, only the last value was stored and other values were lost. This issues was fixed with CC-MAIN-2024-51, see ia-web-commons#18. All WAT files from CC-MAIN-2013-20 until CC-MAIN-2024-46 are affected.
Erratum:
Erroneous title field in WAT records
The "Title" extracted in WAT records to the JSON path `Envelope > Payload-Metadata > HTTP-Response-Metadata > HTML-Metadata > Head > Title` is not the content included in the <title> element in the HTML header (<head> element) if the page contains further <title> elements in the page body. The content of the last <title> element is written to the WAT "Title". This bug was observed if the HTML page includes embedded SVG graphics.
The issue was reported by the user Robert Waksmunski:
- https://groups.google.com/g/common-crawl/c/ZrPFdY3pPA4/m/s5D_8wCJAAAJ
- WAT extractor: Document title bug ia-web-commons#36
...and was fixed for CC-MAIN-2024-42 by commoncrawl/ia-web-commons#37.
This erratum affects all crawls from CC-MAIN-2013-20 until CC-MAIN-2024-38.
Erratum:
Incorrect fetch_time metadata
In crawls CC-MAIN-2016-36 to CC-MAIN-2016-50, and CC-MAIN-2018-34 to CC-MAIN-2019-47 the fetch_time metadata for robots.txt might be incorrect. The correct times can be found in collinfo.json. See the related issue (commoncrawl/nutch#14) for more information.
Erratum:
Charset Detection Bug in WET Records
The charset detection required to properly transform non-UTF-8 HTML pages in WARC files into WET records didn't work before November 2016 due to a bug in IIPC Web Archive Commons (see the related issue in the CC fork of Apache Nutch). There should be significantly fewer errors in all subsequent crawls. Originally discussed here in Google Groups.
Erratum:
Missing Language Classification
Starting with crawl CC-MAIN-2018-39 we added a language classification field (‘content-languages’) to the columnar indexes, WAT files, and WARC metadata for all subsequent crawls. The CLD2 classifier was used, and includes up to three languages per document. We use the ISO-639-3 (three-character) language codes.
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