F5Bot review: what it does, what it costs, who it fits

F5Bot has run since 2017. It watches Reddit, Hacker News and Lobsters for your keywords and alerts you when they appear. On Reddit it reads posts and comments in every subreddit and checks every few minutes.

You sign up with an email address and add keywords. There's no website to paste and no project to configure.

The free plan comes with basic filter flags. Advanced filtering lets you narrow by subreddit, exclude terms and require keywords that appear together. The Gold plan adds AI filtering, where you describe in plain language what you want.

Alerts arrive by email, either instantly, in batches or as a daily digest. Slack and Discord work through webhooks. The page also lists RSS and JSON feeds and programmatic access.

Monthly prices on 17 October 2026:

This example is made up to show how it works. Say you add the keyword "invoicing" in F5Bot. In one day you might get a student asking how invoicing works, a freelancer sharing a template, a vendor announcing a feature, and a small business owner who is fed up with their current tool and wants something simpler. F5Bot sends you all four, since each one contains the word. You narrow the pile with the advanced flags (subreddit, excluded terms, co-occurring keywords) and the Gold plan's AI filtering.

When someone on Reddit asks how to monitor Reddit for keywords, F5Bot is the tool people name most often. In 13 threads we read on 1 November 2026, 24 of 147 commenters mentioned it, more than any other tool. Most use it as a free way to start getting email alerts on a few keywords. When the volume grows, they add filtering by hand or with another tool. The counts and our one-week noise test are in Reddit monitoring tools Redditors use.

F5Bot fits anyone who wants to know when a word shows up on Reddit, Hacker News or Lobsters, at a price that starts at nothing: founders watching their brand name and a release, open source maintainers, researchers following a topic. It also works if you want feeds to plug into your own tools.

These aren't criticisms. We looked for them on its home page and didn't find:

• Reply drafting.
• A buying-intent score.
• X as a source. It lists Reddit, Hacker News and Lobsters.

A keyword alert tells you a word appeared. Figuring out which posts come from buyers is left to you.

HearBuyers does that second step. It reads X and Reddit, scores each post from 0 to 100 for buying intent, highlights the sentence that shows the need, and drafts a reply for a person to approve and post. It starts from your website instead of a keyword list. It doesn't cover Hacker News or Lobsters.

Many teams keep F5Bot for mentions and add HearBuyers for buyers. Read the F5Bot alternative page, the HearBuyers vs F5Bot comparison, or see how Reddit keyword alerts work.

Keep your free F5Bot account running, then paste your website into HearBuyers and compare which matches each one finds this week.