open-index/cc-host-dataset

CC Host Dataset — CC-MAIN-2026-21

A per-URL index of the entire Common Crawl with host-level rank signals. Every URL captured by the crawler becomes one row, enriched with 20 raw CDX fields and harmonic centrality rank from the CC web graph. The dataset covers roughly 1.9 billion URLs across ~262 million hosts.

22 / 280 shards committed for crawl CC-MAIN-2026-21 — new shards added every ~4 minutes.

Stats

Metric	Value
Crawl	CC-MAIN-2026-21
Shards committed	22 / 280
URLs indexed	~—

Schema

Each row is one URL capture. Twenty fields come from CC CDX Parquet; six come from the CC web-graph rank table.

Identity

Field	Type	Description
url	string	Full crawled URL
surt	string	SURT canonical form — sort key for CDX range lookups
host	string	Forward hostname (www.example.com)
rd	string	Registered domain / eTLD+1 (example.com)
tld	string	Effective TLD (com, co.uk)
proto	string	http or https

Fetch result

Field	Type	Description
st	int32	HTTP status code
redir	string	Final redirect target URL (empty if none)
ts	string	Fetch timestamp — ISO-8601
bytes	int64	WARC record length in bytes

Content

Field	Type	Description
mime	string	Detected MIME type (text/html, application/pdf, …)
mime_d	string	Declared MIME from Content-Type header
charset	string	Character set from Content-Type
lang	string	Content language(s), comma-separated BCP-47
trunc	string	Truncation reason (bytes, disconnect, …) or empty
digest	string	SHA-1 content hash — use for dedup and change detection

WARC pointer

Field	Type	Description
warc_f	string	Relative WARC file path on data.commoncrawl.org
warc_o	int64	Byte offset into the WARC file
robots_ok	bool	robotstxt_forceget — robots.txt allowed the crawl
crawl	string	CC crawl ID (CC-MAIN-2026-21)

Rank signals (from CC web graph)

Field	Type	Description
harmonic_pos	int64	Position in harmonic centrality ranking (1 = most central)
harmonic_val	float64	Raw harmonic centrality score
pagerank_pos	int64	PageRank position
pagerank_val	float64	Raw PageRank score
graph_id	string	Web-graph release ID

Usage

DuckDB — no download required

-- Install httpfs extension once
INSTALL httpfs; LOAD httpfs;

-- Top English hosts by rank
SELECT host, rd, harmonic_pos, count(*) AS urls
FROM read_parquet(
  'hf://datasets/open-index/cc-host-dataset/data/crawl=CC-MAIN-2026-21/subset=urls/*.parquet'
)
WHERE st = 200 AND lang LIKE '%en%'
GROUP BY host, rd, harmonic_pos
ORDER BY harmonic_pos
LIMIT 20;

Fetch raw HTML for any URL (WARC byte-range)

import requests, gzip, duckdb

row = duckdb.sql("""
  SELECT url, warc_f, warc_o, bytes
  FROM read_parquet('hf://datasets/open-index/cc-host-dataset/data/crawl=CC-MAIN-2026-21/subset=urls/hosts-a.parquet')
  WHERE url = 'https://www.example.com/'
""").fetchone()

url, warc_f, warc_o, length = row
resp = requests.get(
  f"https://data.commoncrawl.org/{warc_f}",
  headers={"Range": f"bytes={warc_o}-{warc_o + length - 1}"}
)
html = gzip.decompress(resp.content)
print(html[:500].decode(errors="replace"))

Detect content changes across crawls

import duckdb

result = duckdb.sql("""
  WITH new AS (
    SELECT url, digest
    FROM read_parquet('hf://datasets/open-index/cc-host-dataset/data/crawl=CC-MAIN-2026-21/subset=urls/hosts-a.parquet')
    WHERE st = 200
  ),
  old AS (
    SELECT url, digest
    FROM read_parquet('hf://datasets/open-index/cc-host-dataset/data/crawl=CC-MAIN-2026-17/subset=urls/hosts-a.parquet')
    WHERE st = 200
  )
  SELECT count(*) AS changed_urls,
         round(count(*) * 100.0 / (SELECT count(*) FROM new), 2) AS pct_changed
  FROM new JOIN old USING (url)
  WHERE new.digest != old.digest
""").fetchone()
print(f"{result[0]:,} URLs changed ({result[1]}%)")

Multi-crawl comparison with hive partitioning

-- DuckDB extracts 'crawl' and 'subset' as columns automatically
SELECT crawl, count(*) AS urls, count(DISTINCT host) AS hosts
FROM read_parquet(
  'hf://datasets/open-index/cc-host-dataset/data/**/*.parquet',
  hive_partitioning = true
)
GROUP BY crawl
ORDER BY crawl DESC;

Python / HuggingFace datasets

from datasets import load_dataset

ds = load_dataset(
  "open-index/cc-host-dataset",
  split="train",
  streaming=True
)
for row in ds:
    print(row["url"], row["host"], row["harmonic_pos"])
    break

How it was built

1. CDX extract — all 302 CC CDX Parquet files (~570 MB each, ~184 GB total) are downloaded in parallel with pure-Go workers. parquet-go column projection reads only the 20 needed columns; the rest are skipped. Each row is fanned to one of 28 per-prefix gzip-JSONL writers in a single pass.

2. Rank split — the CC web-graph host rank table (~5 GB gzipped TSV) is downloaded once and split into 28 per-prefix files.

3. Shard build — for each prefix, the rank map is loaded into memory (~300 MB), the JSONL stream is iterated, and each row is joined with the rank entry for its host. Output is one Parquet file per prefix, compressed with ZSTD level 3.

4. Publish — each shard is committed to HuggingFace immediately after it is built. Commit path: data/crawl={crawl}/subset=urls/hosts-{prefix}.parquet. The dataset is usable before all shards complete.

Built with ccrawl v0.2.4.

License

Data is derived from Common Crawl, released under the Open Data Commons Attribution License (ODC-By). You must attribute Common Crawl when using or redistributing this dataset.