What X's Open-Source Code Says About Reach (October 2026)
X's public code, read October 16, 2026: a 48-hour window, a lift for fresh posts from small accounts, a cut for posting in a row, no replies to non-followers.
X's open-source For You code, read on October 16, 2026, sets five rules that shape the reach of every post. A post can only be recommended for 48 hours. A fresh original post from a small account can get one lift. Extra posts by the same author in one feed are cut. Replies and reposts from accounts a viewer does not follow are removed, and the rest of out-of-network content is discounted.
None of these rules is a shadowban. They apply to every account, every day.
What does X's open-source code cover?
X's public repository xai-org/x-algorithm contains the code that decides which posts a viewer sees in the For You feed. Its README says the feed combines posts from accounts the viewer follows with posts found by machine learning, filters them, then ranks them with a transformer model.
Many values are read from a configuration system. X's README says cron scripts set the defaults in the code to "the primary production values". The numbers below are those published defaults, read at commit 92f0918 of October 15, 2026.
The repository is republished almost every day. A value can change from one commit to the next.
How long can a post stay in the For You feed?
Free, no login, results in seconds.
A post can appear in X's For You feed for 48 hours at most. The For You pipeline runs an AgeFilter that removes any candidate post older than MAX_POST_AGE = 48 * 60 * 60 seconds, before any scoring. The same 48-hour limit is written into the TweetMixer source.
After 48 hours, the post still exists. People can see it on the author's profile, in search, in a conversation or through a link. It is no longer a candidate for new recommendations.
Does X give small accounts a boost?
Yes. X's code contains a cold-start step that can lift one post per feed request to the score of the 16th-ranked post in that feed. X's README calls it the New-Author Boost.
With the production defaults published by X, a post qualifies only if all of these are true:
| Condition | Published default |
|---|---|
| Type of post | An original post, not a reply and not a repost |
| Author's followers | 50,000 or fewer (ColdStartFollowerCap) |
| Age of the post | Less than 2 hours (ColdStartMaxPostAgeSecs = 7200) |
| Views in Home so far | Fewer than 200 (ColdStartImpressionThreshold) |
| Current rank | Within the top 97% of the viewer's scored posts |
The step is on by default (EnableViewerColdStart). For viewers outside its test groups, any author can qualify. For viewers inside a test group, only authors of the matching group can.
The code picks a single post per request among those that qualify. It raises that post's score to at least the score of the 16th post, never lowers it.
Does posting several times in a row hurt reach?
Posting several times in a row lowers the score of each extra post in the same viewer's feed. X calls this Author Diversity. The code multiplies each post after an author's first by (1 - floor) × decay^k + floor, where k is the number of the author's posts already ranked above it.
With the published defaults, decay is 0.5 and the floor is 0.25:
| Post by the same author in one feed | Multiplier |
|---|---|
| 1st | 1 |
| 2nd | 0.625 |
| 3rd | 0.4375 |
| 4th | 0.34375 |
| Any later post | Never below 0.25 |
The multiplier applies within one feed request. It does not penalize the account. It means a viewer is much more likely to see one post by you than five.
Do replies and reposts reach people who do not follow you?
Replies and reposts from accounts a viewer does not follow are removed from that viewer's For You feed before scoring. X's OONRetweetReplyFilter drops every out-of-network repost, and every out-of-network reply unless a setting allows it.
Two settings control the exception for replies:
EnablePhoenixOonReplieslets replies found by X's retrieval model through. Its published default is off.PhoenixOonRepliesRootOnly, added to the code in October 2026, limits that exception to replies to the original post of a conversation. Its published default is off.
The same filter removes any reply whose parent post is missing.
People who already follow you can still see your replies in For You. Anyone can see them in the conversation itself, unless a restriction such as a ghost ban or reply deboosting applies.
Are posts from accounts you do not follow discounted?
Posts from accounts a viewer does not follow are multiplied by 0.75 in the published defaults (OonWeightFactor). X's README describes the same discount for replies and reposts from accounts the viewer does follow.
For a viewer whose account is new, the code can apply a separate factor, NewUserOonWeightFactor, set to 0.00001. The age below which a viewer counts as new defaults to 0 seconds, so this factor applies to no one with the published defaults.
What about accounts flagged for adult content?
X's OONNsfwSimclustersFilter removes posts from authors flagged for adult content when they come from SimClusters, one of the sources of out-of-network posts, and the viewer does not follow the author. Followers are not affected by this filter.
Adult content is handled by other rules too, in X's visibility filtering. The glossary entry on sensitive media explains how account labels for sensitive content hide posts from people who do not follow the account.
What does the code suggest doing?
These points follow from the published code only. X does not publish how much each rule weighs against the ranking model's predictions.
- Post originals to reach new people. Replies and reposts from you are removed from the For You feed of people who do not follow you.
- The first 2 hours count most for a small account. The cold-start lift needs a post under 2 hours old with fewer than 200 views in Home.
- Space your posts. A second post in the same viewer's feed keeps 62.5% of its score, a third about 44%.
- Expect a 48-hour life in For You. Older posts drop out of recommendations, even when they keep getting likes.
How do you know whether your account is restricted?
If your reach stays low for more than a few days, check whether X restricts your account. These five rules apply to everyone. A shadowban is different: a restriction placed on one account by X's visibility filtering.
A free check on Shadowban Radar tests the 4 restrictions on any public handle, with no login: search suggestion ban, search ban, ghost ban and reply deboosting. Our guide to shadowban durations explains how long each one usually lasts.
Sources
Read on October 16, 2026, in the xai-org/x-algorithm repository at commit 92f0918, published October 15, 2026.
- README.md: the published defaults and the production values.
- config.rs:
MAX_POST_AGE = 48 * 60 * 60. - phoenix_candidate_pipeline.rs: the order of the pre-scoring filters, including the 48-hour filter.
- author_cold_start.rs: who qualifies for the cold-start lift and how the score is raised.
- param.rs: the cold-start defaults.
- scoring.rs: the Author Diversity formula and the out-of-network multiplier.
- vm-ranker/params.rs: the defaults for Author Diversity and the out-of-network factors.
- oon_retweet_reply_filter.rs: the filter for out-of-network replies and reposts.
- param.rs: the two reply settings and their defaults.
- oon_nsfw_simclusters_filter.rs: the filter for authors flagged for adult content.
Shadowban Radar is not affiliated with X Corp. For how X's own label report relates to a live check, see X's Under the Hood.
