Secrets of the LessWrong RSS Feed

Brendan Long23 Feb 2026 20:12 UTC
34 points
6 comments4 min readLW link

LessWrong’s RSS feed includes all recently published articles by default, but it has a bunch of undocumented features available with query params.

Warning: The only officially supported options are view=frontpage, view=curated, and karmaThreshold. Other options may break in the future.

There’s also a full GraphQL API if you have needs beyond this, but the RSS feed is nice if you want it to work in a normal feed reader.

LessWrong RSS Feed Builder

Since there’s a lot of options, I also built a tool to generate LessWrong RSS feed URLs.

Full Documentation

Note: This was generated by Claude after reading the source code for feed.xml and related utility code. Again, only view=frontpage, view=curated, and karmaThreshold are officially supported.

Query Parameters

ParameterTypeDescription
typestringSet to comments for comment feeds, otherwise returns posts
viewstringFeed type/​view (see views below). Defaults to rss
karmaThresholdnumberMinimum karma for posts to appear (see threshold logic below)
filterSettingsJSONAdvanced filtering (JSON-encoded object)
postIdstringFilter comments to a specific post
tagIdstringFor tagRelevance post view or tag comment views
userIdstringFilter by author user ID
parentCommentIdstringFor commentReplies view—replies to a specific comment
parentAnswerIdstringFor repliesToAnswer view—replies to a specific answer
topLevelCommentIdstringFor repliesToCommentThread view—full thread under a comment
forumEventIdstringFor forumEventComments view
sortBystringSort mode for views that support it (see per-view notes)

Post Feed Views

ViewDescriptionSort Order
rss (default)All newest postspostedAt descending
frontpageRssFrontpage posts onlyfrontpageDate descending
curatedRssCurated posts onlycuratedDate descending
communityRssNon-frontpage posts with karma > 2postedAt descending
metaRssMeta posts onlypostedAt descending
tagRelevancePosts by tag (requires tagId param)Tag relevance score

Note: View names can use either camelCase (frontpageRss) or kebab-case (frontpage-rss).

Comment Feed Views

All comment views require type=comments. The limit is hardcoded to 50 results.

General

ViewDescriptionSort
rss (default)Recent comments with positive score (alias for recentComments)postedAt desc
recentCommentsRecent comments with positive scorepostedAt desc
allRecentCommentsAll recent comments including neutral/​negative scorepostedAt desc
commentRepliesReplies to a specific comment (requires parentCommentId)postedAt desc
moderatorCommentsComments posted with a moderator hatpostedAt desc

Per-Post (require postId)

These views exclude answers and answer-replies (filter answer: false, parentAnswerId: null).

ViewDescriptionSort
postCommentsNewComments on a post, newest firstpostedAt desc
postCommentsOldComments on a post, oldest firstpostedAt asc
postCommentsTopComments on a post, highest karma firstbaseScore desc
postCommentsBestComments on a post, best firstbaseScore desc
postCommentsMagicComments on a post, magic/​Wilson sortscore desc
postCommentsRecentRepliesComments on a post, by recent subthread activitylastSubthreadActivity desc
postsItemCommentsRecent non-deleted comments on a postpostedAt desc
questionAnswersAnswers to a question post (supports sortBy)baseScore desc
answersAndRepliesAnswers and their replies (supports sortBy)baseScore desc
debateResponsesDebate responses on a postpostedAt asc
recentDebateResponsesRecent debate responses on a postpostedAt desc

Per-User

ViewDescriptionSort
profileCommentsComments by a user (supports sortBy)postedAt desc
profileRecentComments(Deprecated) Recent comments by a userpostedAt desc

Shortform /​ Quick Takes

ViewDescriptionSort
shortformTop-level shortform commentslastSubthreadActivity desc
topShortformTop shortform by score (supports before/​after)baseScore desc
shortformFrontpageFrontpage shortform (recent, filtered by quality)score desc

Per-Tag (require tagId)

ViewDescriptionSort
tagDiscussionCommentsDiscussion comments on a tagdefault
tagSubforumCommentsSubforum comments for a tag (supports sortBy)lastSubthreadActivity desc

sortBy Values

Views that support the sortBy parameter accept these values:

ValueSort Order
topbaseScore descending
new /​ newestpostedAt descending
old /​ oldestpostedAt ascending
magicscore descending
recentCommentslastSubthreadActivity descending

Karma Threshold Logic

The karmaThreshold parameter determines when posts appear in the feed based on when they reached certain karma levels. Posts have timestamps for when they exceeded various karma thresholds.

Input values are rounded to the nearest supported threshold:

Input RangeActual ThresholdDate Field Used
< 16 (or not set)2scoreExceeded2Date
16-3630scoreExceeded30Date
37-5945scoreExceeded45Date
60-9975scoreExceeded75Date
100-161125scoreExceeded125Date
>= 162200scoreExceeded200Date

The feed item’s date is the later of:

  1. The karma threshold date (when post reached the threshold)

  2. The view-specific date (e.g., frontpageDate for frontpage feed)

This allows higher-threshold feeds to show older posts that recently became popular.

  1. ^

    I don’t know where to get userIds from the UI, so I used the GraphQL API:

    $ curl -s -X POST https://​​www.lesswrong.com/​​graphql \
  -H ‘Content-Type: application/​json’ \
  -d ‘{”query”: “query { user(input: { selector: { slug: \”brendan-long\” } }) { result { _id } } }”}’
{”data”:{”user”:{”result”:{”_id”:”piR3ZKGHEp6vqTo87″}}}}
  2. ^

    You can find postIds in the post URL, i.e. the postId for https://​​www.lesswrong.com/​​posts/​​ioZxrP7BhS5ArK59w/​​did-claude-3-opus-align-itself-via-gradient-hacking is ioZxrP7BhS5ArK59w.

Brendan Long23 Feb 2026 20:12 UTC
34 points
6 comments4 min readLW link