Why Did My Reddit Keyword Alert Miss a Thread?

If you can find a Reddit thread manually but your keyword alert missed it, first check what the alert actually searched. A match can disappear before scoring, after scoring, or because the search never returned it. Those are different failures with different fixes.

This is a source-level walkthrough of RedditScanner's search and scoring implementation as checked on October 14, 2026. It describes the code, not measured recall on live Reddit. Accounts on this site are currently closed, so the steps below also work as a manual audit of another monitoring setup.

Recreate the query before changing your keywords

Save the missed thread URL, community, creation time, the exact phrase you expected to match, and the time you ran your alert. Then repeat the search with the same community and time window. Reddit's search guidance distinguishes filters and sorts; comparing a week-old newest-first post search with an all-time relevance search is not a fair recall test.

Our implementation asks Reddit for posts sorted newest, limited to 50 results from the past week. A configured subreddit restricts that search to its own posts; without one, it searches across Reddit. If a busy query returns more than 50 matching posts, the oldest of those results are outside this single request. The code does not paginate. A thread older than a week is outside the requested window. Neither case tells you that the keyword itself is wrong.

Check the post's title and body, not only its comments. Reddit separates post and comment search; this scanner searches posts and never runs a comment search. A product question that only appears in a reply is therefore outside its search scope.

A returned post can still be filtered out

RedditScanner scores returned posts using age, comment count, votes, subreddit size, question words in the title, and whether the keyword appears in the title or body. The public scoring guide lists those factors. The scanner then drops results below the monitor's minimum score. That threshold ranks an opportunity for review; it is not a relevance verdict.

If you can inspect a monitoring pipeline, compare its raw search result with the scored result at a low threshold. A post present in raw search but absent after scoring is a filtering issue. One absent from raw search calls for a scope, window, result-limit, or upstream-search check. Do not "fix" the latter by lowering a score threshold: the post never reached the scorer.

There is one particularly easy false reassurance in our current code: a non-successful Reddit response or a fetch error produces an empty array, just like a successful search with no hits. The scanner does log an error on the server, but an empty list alone cannot distinguish those outcomes. Treat a sudden zero across unrelated queries as a request-health question before concluding your market went quiet.

Keep a small miss ledger

For each missed URL, record whether it was inside the chosen subreddit, inside the past-week window, present in the newest-first results, in the first 50, and above the score threshold. Mark an upstream error separately from a genuine empty search. Recheck the original Reddit URL because removed or inaccessible content may no longer be available to inspect.

This ledger tells you whether to narrow a broad query, add a community-specific search, review a threshold, or investigate a failed request. It cannot calculate recall unless you also define a complete set of relevant threads, which a single Reddit search does not provide.