Someone is asking for a product like yours on Reddit right now. Without alerts, you'll find the thread three weeks late — after a competitor got recommended.
Quick answer: Reddit has no built-in keyword alerts — its native notifications only cover replies, username mentions, and followed communities. The most complete setup is Prowlo's Keyword Monitor: type a keyword, it searches all of Reddit daily, catches meaning-adjacent threads exact matching misses, and delivers to Slack, webhook, or your AI agent — 20 keywords on the $19/mo plan. The free routes: F5Bot (exact match, email — free plan now capped at 5 keywords), Reddit RSS + Zapier/Slack (DIY), Google Alerts (days late). Setup steps and where each one breaks, below.
Key takeaways
- Reddit has no native keyword alerts. Notifications cover replies, mentions, and follows — never keywords. Every alert runs through an external tool.
- Exact match misses the best threads. "Anyone know a good GummySearch replacement?" contains no keyword you'd guess. Semantic matching catches it.
- Free got smaller in 2026. F5Bot's free plan is now 5 keywords, 20 alerts/day, ~2 hours late. RSS + Slack is the workaround.
- The useful reply window is 2–6 hours. Faster than hourly rarely helps; slower than a day means commenting into a dead thread.
- Your agent can run the whole thing. Over MCP, an AI agent can create keywords, manage watchers and alerts, and tune its own setup.
Option 1: Prowlo — Reddit-wide keyword search plus semantic alerts
The structural problem with every free option is exact matching: the highest-value threads — "anyone know a good GummySearch replacement?" — often don't contain your keyword at all. (GummySearch, the Reddit research tool 140,000+ people used, shut down November 30, 2025 over Reddit API licensing costs — what replaced it.) 
attacks that from two directions at once.
Keyword Monitor covers breadth. Type a keyword — your brand, a competitor, a category phrase — and Prowlo searches all of Reddit for it once a day. The query syntax handles broad terms (invoice), exact phrases ("invoice generator"), and wildcard endings (invoic* also catches "invoices" and "invoicing"). Every find lands tagged with your labels, and first results show up minutes after you add a keyword.
Watchers cover depth. Point one at each subreddit where your buyers are and Prowlo crawls it hourly — posts and comments — with intake filters (minimum score, language, post age, exclude promo accounts) dropping the noise before it reaches you.
Both feed the same place: every match is embedded for semantic search and stored in your Dataset. That's the part no alert tool replicates — "what did r/SaaS say about us in March" is a query, not archaeology, and meaning-adjacent threads surface even when they never used your exact phrase. High-relevance hits fire to Slack or a webhook, and your AI agent runs the same searches over MCP from Claude or Cursor.
Setup: add your keywords to Keyword Monitor (3 on the free trial, 20 on the paid plan), optionally add Watchers for your core communities, pick a delivery channel. $19/mo flat after a 14-day trial, no card. For scale: Brand24's entry plan tracks 3 keywords for $249/mo ($199 on annual billing), and Syften's 20-filter tier runs $49.95/mo — though Syften's new MCP support sits on its $119.95/mo PRO tier, versus MCP included in Prowlo's $19 plan (August 2026 list prices). Prowlo is also read-only by design — no auto-replies, nothing that gets your account banned. And the setup itself is delegable: over the same MCP, your AI agent can create and manage Keyword Monitors, Watchers, and alerts — it writes the keyword list from what it already knows about your product, then tunes it as results come in.
If all you need is exact-match on a single brand name at $0, F5Bot below does that fine. Everything past that one narrow case — broad terms, comments, history, delivery beyond email, an agent reading the results — is where Prowlo pulls away.
Option 2: F5Bot — free email alerts
F5Bot has been the default free answer for a decade: enter keywords, get an email when they appear in Reddit posts or comments (plus Hacker News and Lobste.rs). In mid-2026 it restructured into paid tiers, and the free plan shrank to 5 keywords with 20 alerts/day and roughly 2-hour delivery, with an ad in each email.
Setup: create an account, add keywords, done. No dashboard on free — alerts arrive by email only.
Where it breaks:
- Exact match only. "Prowlo" works. "best tool for monitoring subreddits" — the thread you'd actually pay for — never matches.
- Volume caps. Free is capped at 20 alerts/day total, so a popular term goes quiet mid-day. Paid tiers raise the caps: Silver $9.99/mo (20 keywords, 100 alerts/day, 5-minute delivery), Gold $49.99/mo (200 keywords, RSS/JSON, AI filtering, Slack/Discord), Platinum $214.99/mo (API and webhooks).
- Email-only delivery on free (Slack/Discord start at the $49.99 tier), and no history — a deleted alert is gone.
Option 3: Reddit RSS feeds + Zapier or Slack
Reddit still exposes RSS everywhere, which makes a DIY pipeline possible without touching the API:
- Search feed:
https://www.reddit.com/search.rss?q=your+keyword&sort=new - Subreddit firehose:
https://www.reddit.com/r/SaaS/new/.rss - Comments:
https://www.reddit.com/r/SaaS/comments/.rss
Setup: pipe a feed into Zapier, Make, or Slack's built-in /feed command; add a keyword filter step; deliver anywhere.
Where it breaks: string-match filtering only, one automation per subreddit or query, silent breakage when Reddit adjusts rate limits, and someone has to own the plumbing. A weekend project that becomes a chore — but you control every piece.
Option 4: Google Alerts with site:reddit.com
The classic hack: create a Google Alert for "your keyword" site:reddit.com. It fires when Google indexes the thread — hours to days after the conversation happened — and it misses most threads entirely. Fine as a free backstop for evergreen mentions; useless for catching a conversation while it's alive.
Option 5: Can Reddit itself notify you about keywords?
Reddit itself will notify you about replies, mentions of your username, and activity in communities you follow — but not keywords. There is no native keyword alert, on web or mobile. Third-party mobile apps ("Alerts for Reddit" on Android and similar) wrap keyword polling in an app; reviews are mixed and they inherit Reddit's API constraints. If you want alerts on your phone, the more reliable path is any tool from this list that delivers to Slack — Slack's mobile notifications do the rest.
The comparison, side by side
How do you track Reddit keywords with minimum noise?
Ten keywords with no filtering means an hour a day of deleting alerts — the top complaint in every "how do you track Reddit keywords" thread. Four filters, in order of impact:
- Split breadth from depth. Run broad brand and competitor terms Reddit-wide (Keyword Monitor handles this in Prowlo), and reserve firehose-level attention for the 5–15 communities where your buyers actually are. Watching everything at full volume is how alert fatigue starts.
- Negative keywords and intake filters. Track "keyword tracking" and exclude "hiring", "job", "course". Boolean tools (Syften) support exclusions; Prowlo's intake filters go further — minimum score, language, post age, and repost status are checked before anything reaches your Dataset. F5Bot free has no filtering at all.
- Score/age thresholds. A post with zero upvotes after six hours is usually not worth a ping.
- Semantic ranking instead of more keywords. The instinct when you miss threads is adding keyword variants — which multiplies noise. Semantic matching inverts it: fewer keywords, ranked results, and a relevance score you can threshold. Of the tools here, only Prowlo does this.
For what to track: brand + misspellings, competitor names, and the five buying-intent phrasings ("alternative to", "anyone recommend", "switching from") that signal someone is actually shopping.
FAQ
What's the best Reddit keyword alert tool?
Prowlo, for anything beyond single-brand exact matching: Keyword Monitor searches all of Reddit daily, semantic search catches threads your keywords miss, matches store in a searchable Dataset, and delivery covers Slack, webhooks, and MCP for AI agents — 20 keywords at $19/mo. F5Bot remains the best $0 option for exact-match brand terms.
Can Reddit notify me when a keyword is mentioned?
No — Reddit's native notifications cover replies, username mentions, and followed communities, not keywords. Every keyword alert requires an external tool: Prowlo, F5Bot, an RSS pipeline, or Syften.
What's the best free Reddit keyword alert tool?
F5Bot: 5 keywords, posts and comments, email delivery, at $0 — with a 20-alerts/day cap and ~2-hour delay since its mid-2026 repricing. Reddit RSS feeds into Slack are the best free option if you want more keywords or delivery somewhere other than email.
Does Mangools do Reddit keyword alerts?
No. Mangools' free Reddit Threads Finder is keyword research — it finds search queries where Reddit threads rank in Google, useful for picking what to target. It doesn't watch Reddit or send alerts. For actual notifications you still need a monitoring tool like Prowlo, F5Bot, or Syften.
Can I get Reddit keyword alerts on my phone?
Indirectly, and it works better than the app-store options: route alerts to Slack (via Prowlo, Syften, or an RSS pipeline) and let Slack's mobile push handle the phone part.
How fast do alerts need to be?
The useful window for joining a thread is roughly its first 2–6 hours — early comments get the visibility. Faster than hourly rarely changes outcomes; slower than a day means you're commenting into a dead thread.
Do these tools monitor comments or just posts?
It varies, and it matters — many buying conversations happen in comments under someone else's post. Prowlo, F5Bot, and Syften cover both; RSS pipelines cover posts easily and comments only per-subreddit; Google Alerts effectively covers neither in time to act.