The Reddit Archive

Every public Reddit comment and submission from June 2005 to July 2026, as zstd-compressed ndjson — 254 consecutive months, about 4.3 TB, held at the Laboratory for Social Minds, CMU. Everything through December 2021 is on disk now; the later months are still arriving and appear in the grid below as each one lands. The first two thirds of it, to the end of 2021, is the corpus as it stood before language models began writing into it. Four curated r/math and r/askphilosophy datasets are drawn from it, small enough to download in a minute and open to anyone.

CMU

The monthly dumps below are served only to Carnegie Mellon IP ranges — on-campus networks and the CMU VPN. From anywhere else they return 403. The curated datasets further down are small and open to everyone.

The archive, by year

One link per monthly file, June 2005 to July 2026, continuous. Sizes are on-disk and appear on hover; downloads support range requests, so a dropped transfer resumes rather than restarting. Comments begin in December 2005, six months after submissions, because that is where the upstream dumps begin — the dashed months are absent from the source, not missing here. Amber months are still downloading. The grid is drawn from the archive index and refreshes itself, so months appear as they land.

The whole archiveloading…
All 392 files of the 2005–2021 set decode cleanly. Every dump was decompressed end to end and every one succeeded, which is a stronger statement than a size check: zstd verifies an XXH64 checksum over each frame’s contents. An earlier pass found 11 damaged files; the bad pieces were re-fetched from the swarm and re-verified. Months arriving now are verified as they land: every piece is checked against the torrent before it is written, and a month is only linked here once all of its bytes are present.

Curated datasets

Single-subreddit extracts, built by one pass over all 392 monthly files. These are small enough to download over a coffee break and are served to everyone, with no IP restriction. Each is newline-delimited JSON, zstd-compressed, one record per line — and unlike the dumps they need no --long=31, so a plain zstd -dc works.

Every r/math submission in the archive, unfiltered — no score cut, deleted and removed posts kept exactly as the dumps recorded them. One JSON object per line.

Submissions
213,451
Size
37.8 MiB
Range
2008-01 → 2021-12
Comments
none — posts only

The best-scoring r/math threads with their comment sections. Each line is a submission with every comment on it nested under "comments", oldest first. The score cut was chosen by compressing candidate builds until this file matched the posts-only file above: comments outweigh submissions by roughly fifty to one, so equal size buys depth instead of breadth.

Score cut
≥ 316
Submissions
2,953 (1.4% of all)
Comments
343,050
Size
38.4 MiB (1.02× posts)
Range
2009-07 → 2021-12

Every r/askphilosophy submission in the archive, unfiltered — no score cut, deleted and removed posts kept exactly as the dumps recorded them. One JSON object per line.

Submissions
131,007
Size
29.0 MiB
Range
2011-02 → 2021-12
Comments
none — posts only

The best-scoring r/askphilosophy threads with their comment sections. Each line is a submission with every comment on it nested under "comments", oldest first. The score cut was chosen by compressing candidate builds until this file matched the posts-only file above: comments outweigh submissions by roughly fifty to one, so equal size buys depth instead of breadth.

Score cut
≥ 29
Submissions
4,531 (3.5% of all)
Comments
181,224
Size
29.3 MiB (1.01× posts)
Range
2011-11 → 2021-12
Built from a fully verified archive. Every source dump decodes, so these extracts are complete for the window they cover. They start in 2008 and 2011 rather than 2005 because user-created subreddits did not exist earlier — the 2005–2007 dumps contain only reddit.com, politics, programming and a handful of other original sections.

Using the archive

On ganesha

PathContents
/data/reddit-archive/historical/reddit/submissions/RS_2005-06 … RS_2021-12
/data/reddit-archive/historical/reddit/comments/RC_2005-12 … RC_2021-12
/data2/reddit-archive/curated/public/the curated datasets above
/data/reddit-archive/torrents/every .torrent + download_links.md

Reading a dump

zstd -dc --long=31 RC_2015-01.zst | head -1

The --long=31 window is required — these use a 2 GB compression window and fail to decompress without it. Each line is one JSON object. Field order is not stable between months and fields come and go across the years, so read by key and treat every key as optional; created_utc in particular is sometimes a number and sometimes a string. See PushshiftDumps for iteration helpers.

Source

One torrent covers 2005-06 through 2025-12; only the files through 2021-12 were taken. It is delisted from Academic Torrents — the details page 404s — but the swarm is alive and was observed with 34 seeds. Infohash 3d426c47c767d40f82c7ef0f47c3acacedd2bf44 (magnet). A copy of every .torrent in the collection, including the delisted monthly releases and the per-subreddit split, is on ganesha under /data/reddit-archive/torrents/.

Documentation