Knowledge base chatbot: six tools compared

A knowledge base chatbot is a chat window on your site that answers customers from your own content, such as your help centre, your docs and a few files, rather than from whatever its model learned on the internet. For each question it looks up the passages that fit and writes a short reply from them. A good one also knows where your content stops. When nothing you gave it covers the question, it says so and gets the customer to a person, instead of making up a refund policy.

The tools differ in three ways that matter to a small software company. They read different things, they do different things with a question they can’t answer, and they bill in different ways. Below are six worth weighing, with what each reads, what it does when it’s stuck, and its free plan and first paid plan. We read every figure on the vendors’ own pages on 19 October 2026, and each price links to where we read it.

Deacon is ours, and it’s a knowledge base chatbot for founders without a support team. It answers your customers from your docs, then shows you what they’re stuck on and what they want you to build. It has a free plan.

Six knowledge base chatbots side by side

Deacon is the first row, then the six in the order they’re covered below.

How a knowledge base chatbot finds its answer

A knowledge base chatbot cuts your content into short passages and indexes them. When a question comes in, it finds the few passages closest in meaning, hands them to a language model with the question, and the model writes the reply. That method is retrieval-augmented generation, and grounding AI walks through it a step at a time. When a tool says it’s training on your content, check what it means. SiteGPT’s docs put it plainly, saying training “only builds a searchable index of your content” and doesn’t change the model.

So the reply can only be as good as two things, whether the fact is in your content and whether the search can find it. AI knowledge base covers what belongs in the content, and how to set up an AI chatbot for documentation covers choosing the pages, testing them and keeping them current.

What to check before you choose one

What separates these tools shows up after launch, so check these five things before you choose.

• What it reads. If your help centre lives in Zendesk or Help Scout, a tool that syncs it saves you work. If your answers are spread across your marketing site, a PDF and a Notion page, look for one that takes all three. Intercom, Chatbase, DocsBot AI and SiteGPT connect to Notion, and every tool here reads public web pages.
• What it does when it’s stuck. Ask it three questions your content doesn’t answer, such as a refund you don’t offer or a feature you haven’t built. A good one says it doesn’t know and gives the customer a way to reach you. In SiteGPT, staying on your content is a rule given to the model rather than a filter, and its docs add that the model “can add general knowledge”. Chatbase leaves that rule for you to write. So test it whichever tool you pick.
• What the bill counts. Intercom charges for each outcome and Help Scout for each resolution, on top of seats. Chatbase, DocsBot AI and SiteGPT sell monthly credits or messages, and a bigger model uses more of them. Tidio sells packs of Lyro conversations. Intercom’s page adds that if Fin can’t answer, or the customer asks for a person, you pay nothing.
• How it keeps up when your docs change. Intercom’s own articles reach Fin almost at once, while synced web pages refresh weekly. Chatbase re-reads websites and Notion weekly on Standard and Pro. DocsBot AI refreshes monthly on Personal and weekly from Standard, SiteGPT monthly from Growth, and Tidio weekly on its custom Plus and Premium packages. Help Scout’s sources other than its own Docs are re-synced by hand.
• What it tells you afterwards. The questions it couldn’t answer are your list of pages to write. SiteGPT lists them in Analytics from Growth, DocsBot AI starts question analytics on Standard, and Tidio collects them as Suggestions you can answer with a new Q&A pair.

The six, one by one

Intercom Fin

Fin is Intercom’s AI agent, and it suits a SaaS team that already runs support through Intercom’s help centre and inbox. It answers from Intercom help centre articles, and Intercom recommends writing your content there because native articles reach Fin almost at once. It also reads any public website, snippets and PDFs, and you can use Fin on its own with another helpdesk such as Salesforce or Freshdesk.

Intercom’s FAQ says that when Fin doesn’t know the answer, “it will say that it didn’t find an answer, and it can then hand over to a human.” You pay $0.99 an outcome, at most once a conversation, on top of Essential at $19 a seat a month billed yearly in our read. Intercom is running a price test on Essential, so you may see a different figure. Intercom has no free plan, but its 14-day trial asks for no card. Fin AI pricing explains what counts as an outcome.

Help Scout

Help Scout’s AI agent answers in Beacon, its chat widget, and its help pages now call it Scout. They say Scout evolved from AI Answers, and the pricing page still sells it under that name. It suits a team that already writes its help centre in Help Scout Docs, which Scout draws on, along with public websites, PDFs, Word documents and spreadsheets.

Help Scout’s pricing page promises “no dead ends”, with your team “always a click away”. In Beacon the visitor can start a chat or send a message, and you can list topics, such as billing disputes, that Scout passes straight to your team. Each resolution costs $0.75, charged only when the customer doesn’t ask for more help, and you can set a monthly cap. The free plan gives you 5 users and a Docs site, while the plan table prices AI from Standard, at $25 a user a month billed yearly. A new account gets 3 months of AI resolutions free. Help Scout pricing has the rest of the bill.

Chatbase

Chatbase is a general AI agent builder, and it reads more than most here: files, a crawl or sitemap, links, text, Q&A pairs and Notion pages, plus closed Zendesk or Salesforce tickets on Pro. A change to a source takes effect within seconds, with no retrain button.

The catch for a knowledge base chatbot is its default. Chatbase’s starting instructions ask the agent to help and “direct them to the appropriate resources”, and its docs say that to keep it from answering outside your training data you have to “say so explicitly”. A handover to a person runs through its helpdesk inbox, which the plans list from Standard at $150 a month. There’s no free plan, only a 7-day trial, and Hobby is $40 a month for 700 message credits. Chatbase pricing shows what a credit buys on each model.

DocsBot AI

DocsBot AI is built around documentation and reads the widest range of sources here, more than 28 platforms and source types by its own count, from sitemaps and Notion to Zendesk Guide and helpdesk tickets. Cloud sources start on Personal and ticket sources on Standard. It suits a product with large docs spread across several tools.

Its widget has an escalation button that sends the visitor to your live agents with the conversation, and creating an escalation ticket starts on Standard, at $149 a month. The free plan needs no card and is for personal use, with 100 AI credits a month and 50 source pages. Personal is $49 a month for 5,000 AI credits. DocsBot alternatives sets its plans beside eight other tools.

SiteGPT

SiteGPT reads your site by crawl, sitemap or list of links, files, YouTube transcripts and six connected apps, from Notion to GitHub. It counts your content in pages of 2,500 cleaned characters, 1,000 of them on Starter. It suits a founder who wants a widget trained on the website itself.

Its docs are the most candid here about what happens when your content runs out. The chatbot replies with your fallback message, which you can change, and records the question as unanswered, and its docs call a fallback “often a good result” because “the chatbot did not guess”. The list of unanswered questions is in Analytics from Growth, at $129 a month. There’s no free plan, the 7-day trial takes a card, and Starter is $59 a month for up to 4,000 messages on GPT-4.1 mini. SiteGPT pricing shows how the model you choose changes that count.

Tidio Lyro

Lyro is the AI agent inside Tidio, a live chat and helpdesk tool, and it can also sit on another helpdesk such as Zendesk. It reads up to 100 pages from one website address, or pages you list one by one, along with Q&A pairs, CSV and PDF files, a Zendesk help centre and your shop’s products. It turns a web page into Q&A pairs you can edit.

When a visitor asks for a person, or Lyro can’t answer, it transfers the chat to your team by default. You can have it keep the conversation or create a ticket instead, and out of hours it takes the visitor’s email for the ticket. The questions it couldn’t answer wait under Suggestions. Tidio’s free plan includes 50 Lyro conversations once, and Lyro then costs $39 a month for 50 conversations a month. Tidio pricing explains what counts as a conversation.

Deacon, the knowledge base chatbot that tells you what to build

All six tools answer from your content. Deacon does that too, and it’s built for the founder who reads every support question themselves. What it adds is what those questions tell you.

First, it points you at what to build next. Topics group what customers ask and count the people behind each group, and a group gets a type when one kind of question leads it, so feature asks and bug reports stand apart from how-tos. Analytics › Widget keeps a list of the things visitors ask you to build, quoted as they wrote them. Once questions on one page go unanswered more often than on the others, with enough of them to tell, it names that page.

Second, you can see the questions behind each page. For your most visited pages, Analytics › Website puts the questions people asked Deacon there beside that page’s visits, with how many went unanswered. The Unanswered filter in Conversations lists the questions your content hasn’t covered yet.

Third, the questions it misses turn into a to-do list. Under What needs you, the questions Deacon didn’t know each sit one click from the box where you write the answer. Write it once and Deacon answers from it straight away, shows you the reply it now gives the visitor, and lists the other open questions your answer covers.

Fourth, it fits sites made with AI app builders. Install is one script tag, and it opens on the steps for your site builder when your home page shows which one, with steps for Lovable, Bolt, Replit and Base44 among them. Lovable chatbot and Replit chatbot set building a support chatbot there beside adding Deacon.

The answering itself is quick and careful. Deacon replies in seconds, in the language the visitor writes in. When your content doesn’t cover a question, it says it doesn’t know instead of guessing and asks for the visitor’s email, and your reply from the dashboard appears in their chat. No feature is held back for a higher plan, so the free plan has every one.

Which knowledge base chatbot fits you

Start with where your help content lives today and who answers when the chatbot can’t.

If you already run support in Intercom, Fin is the natural choice, and you pay only for outcomes on top of your seats. If your help centre is in Help Scout Docs, Scout draws on it and keeps your team a click away. If your docs are spread across Notion, Confluence and a helpdesk, DocsBot AI reads the most kinds of source, and Chatbase suits you if you want to build a broader agent and will write its instructions carefully. SiteGPT is the plainest about its fallback, and Tidio Lyro fits an online shop that also wants live chat and its products in the answers.

If you handle support on your own, Deacon was built for you. It answers your customers from the docs you already have, tells you plainly when they run out, and turns what customers ask into a list of what to fix and what to build next.

Questions about knowledge base chatbots

Do I need a help centre before I add a knowledge base chatbot?

No. Every tool here reads public web pages, so your pricing page, your docs and a few files are enough to start. A help centre helps when customers want to browse for themselves. Deacon reads your website, files, pasted text and the answers you write, and the best knowledge base software compares eight tools if you want a help centre as well.

Should I build my own knowledge base chatbot?

You can, with a model’s API and a search index, and it’s a good way to learn how they work. What a built one leaves to you is the rest of the job: deciding what it says when it can’t answer, getting the customer to a person, re-reading your docs when they change and seeing what people asked. That’s most of the work after launch, and it’s what the tools above sell.

Will a knowledge base chatbot make things up?

It can, if it’s allowed to fill gaps from what its model learned elsewhere. Look for one that says it doesn’t know, and test it with questions your content doesn’t answer before customers see it. AI hallucination has real examples and the rules that make a bot admit it doesn’t know.

Is there a free knowledge base chatbot?

Several let you start without paying. Deacon’s free plan includes 50 answers a month and every feature, needs no card and has no end date. DocsBot AI is free for personal use with 100 AI credits a month, Tidio’s free plan has 50 Lyro conversations once, and Help Scout gives a new account 3 months of AI resolutions free. Intercom offers a 14-day trial with no card, Chatbase a 7-day trial, and SiteGPT a 7-day trial that takes a card.

Can a knowledge base chatbot answer my team instead of my customers?

Some can. These six are built mainly for customers, though DocsBot AI connects to Slack from Personal and Chatbase lists Slack on Hobby. Deacon answers visitors on your website only, and your team uses its dashboard to read what customers asked and reply to them.