Table of Contents
- Key takeaways
- What is a knowledge base chatbot?
- Is there a free chatbot for FAQs?
- How these options were ranked
- 4 free and low-cost chatbots for an existing knowledge base
- 1. Tidio: best for a $0 start with a few dozen FAQs
- 2. Botpress: best free plan for teams that can build their own bot
- 3. SiteGPT: best low-cost route to answers from your whole knowledge base
- 4. Help Scout: best for teams whose knowledge base is Help Scout Docs
- How much does a chatbot on a knowledge base cost per year?
- Can you build a free knowledge base chatbot yourself?
- How to choose a free or low-cost knowledge base chatbot
- How to put a chatbot on your existing knowledge base
- Use-case cheat sheet
- Try a chatbot on your knowledge base
- Frequently asked questions
- Basics
- What is a chatbot knowledge base?
- Can a chatbot use my existing knowledge base?
- Free plans
- Is there a completely free chatbot for FAQs?
- Does SiteGPT have a free plan?
- Cost
- How much does a knowledge base chatbot cost per year?
- Is pay-per-resolution cheaper than a flat plan?
- Setup and accuracy
- How long does it take to set up a knowledge base chatbot?
- Will a knowledge base chatbot make up answers?
- Sources
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Sep 21, 2023 03:25 AM
A free chatbot for FAQs exists, but every free plan that answers from a knowledge base stops at 50 to 100 AI conversations, so a steady FAQ chatbot on an existing knowledge base costs about $390 to $1,800 a year at list price.
TL;DR
- Tidio is the cheapest start. The Free plan includes 50 Lyro AI conversations one time, and Lyro costs $32.50 a month billed yearly ($390 a year) for 50 AI conversations a month.
- Botpress has the most generous free plan for builders: 100 conversations, 3 seats and 100MB of knowledge storage. Plus costs $150 a month billed yearly ($1,800 a year).
- SiteGPT has no free plan. Starter costs $59 a month billed monthly, or $39 a month billed yearly ($468 a year), and trains on up to 1,000 pages of your help center, site and files.
- Help Scout gives a free Docs site, but its Envoy chatbot needs a paid plan from $25 a user a month billed yearly, plus $0.75 per AI resolution.
- Billing yearly saves money on every paid route. SiteGPT Starter costs $708 a year billed monthly and $468 billed yearly, a $240 (34%) difference.
Key takeaways
Tool | Best for | Free plan for AI answers | First paid AI step, per year |
1. Tidio | A $0 start with a few dozen FAQs | 50 Lyro AI conversations, one time | $390 billed yearly (Lyro, 50 a month) |
2. Botpress | Teams that can build their own bot | 100 conversations, 3 seats | $1,800 billed yearly (Plus, 250 a month) |
3. SiteGPT | Low-cost answers from a whole knowledge base, no code | None. 7-day trial, credit card required | $468 billed yearly (Starter, up to 4,000 messages a month) |
4. Help Scout | Teams whose knowledge base is Help Scout Docs | Free Docs site, no AI chatbot | $300 for 1 user billed yearly, plus $0.75 per resolution |
What is a knowledge base chatbot?
A knowledge base chatbot is a chat widget that answers questions by reading your existing help articles, FAQs and docs. It retrieves the passage that matches the question and writes an answer from it, a method called retrieval-augmented generation (RAG).
The chatbot does not replace the knowledge base. You still need a place to write and publish the articles, and the guide to knowledge base systems compares those tools. This guide covers the cheaper question: how to put a chatbot on top of the knowledge base you already have.
Is there a free chatbot for FAQs?
Yes, but free plans for AI answers are small. Tidio's Free plan includes 50 Lyro AI conversations that never refill. Botpress Free includes 100 conversations with no top-ups or overages.
That is enough to test answer quality on your own FAQs. It is not enough to run a chatbot on a site with steady traffic. For a wider list of free website chatbots, including live chat tools without AI, see the guide to the best free chatbots for a website.
How these options were ranked
Each option was ranked for one job: answering customer questions from an existing knowledge base at the lowest yearly cost. Five criteria decided the order:
- Cost to start. Whether a $0 plan includes AI answers.
- Yearly cost of the first paid step. List price, billed yearly.
- Knowledge sources. Whether the bot reads a help center, website, files or cloud drives without copying content by hand.
- Setup effort. No-code setup ranks above building a bot.
- Route to a person. Whether the bot can hand a visitor to the team.
Tidio and Botpress rank ahead of SiteGPT because they have free plans and this guide is about the lowest cost. SiteGPT ranks third as the low-cost paid route for teams that want the whole knowledge base answered without building anything.
4 free and low-cost chatbots for an existing knowledge base
1. Tidio: best for a $0 start with a few dozen FAQs
Tidio is a live chat and helpdesk tool with an AI agent called Lyro. Lyro answers from FAQs you upload or scrape from your site, and it can import Zendesk help center articles. The full Tidio review covers the rest of the product.
Key features
- Lyro AI agent with human handoff and knowledge-based responses
- Knowledge from an FAQ upload, an FAQ scraper, a website scraper and Zendesk article import
- Live chat, ticketing and Flows (rule-based chat automations) in one widget
- Lyro can be bought on its own, without a paid helpdesk plan
Pros
- $0 start with no credit card for the trial
- Lowest paid AI step in this guide, $390 a year billed yearly
- Live chat and the AI agent share one inbox
Cons
- The 50 free Lyro conversations are one time and never refill
- The entry Lyro tier covers only 50 AI conversations a month
- Built around FAQs and website pages more than large document libraries
Pricing
Plan | Billed monthly | Billed yearly | What it covers |
Free | $0 | $0 | 50 billable conversations a month, 50 Lyro conversations one time, 100 Flows visitors |
Starter | $29 a month | $24.17 a month | 100 billable conversations a month |
Lyro AI Agent | From $39 a month | From $32.50 a month | From 50 Lyro AI conversations a month |
Rating: 4.6 out of 5 from 1,992 reviews on G2.
Best for: small sites and stores that want to test an AI answer bot on a short FAQ list for $0, then pay for a small monthly AI allowance.
2. Botpress: best free plan for teams that can build their own bot
Botpress is a platform for building AI agents. Its Free plan is the largest free allowance in this guide, but someone has to build the agent, load the knowledge and design the conversation. The Botpress review covers the builder in detail.
Key features
- Knowledge base storage for embeddings: 100MB on Free, 1GB on Plus
- Webchat and WhatsApp channels on every plan
- Help Center on Free, with a custom domain on Plus
- Conversation-based pricing, with AI-only and human-assisted conversations counted the same
Pros
- 100 free conversations, 3 seats and 3 AI agents
- Plus includes $25 of AI usage and unlimited AI agents
- Full control over logic and integrations
Cons
- Building and maintaining the agent takes time
- Free has no top-ups or overages, so volume is capped at 100 conversations
- Plus auto-buys packs of 100 conversations at $65 once usage passes 95% of the quota
Pricing
Plan | Price | Conversations |
Free | $0 | 100 |
Plus | $150 a month billed yearly | 250 a month, then $65 per 100 |
Team | $750 a month billed yearly | 1,500 a month, then $50 per 100 |
Enterprise | Custom | Custom |
Rating: 4.5 out of 5 from 514 reviews on G2.
Best for: technical teams that want a free plan to build and test a knowledge base agent before paying for volume.
3. SiteGPT: best low-cost route to answers from your whole knowledge base
SiteGPT is an AI chatbot that trains on the content you already have and answers in a chat widget. It has no free plan. Starter costs $468 a year billed yearly, about $1.28 a day, and covers up to 1,000 pages of help articles, site pages and documents with no code.
Key features
- Trains on website URLs, sitemaps, files and raw text
- Data source integrations for Google Drive, Dropbox, OneDrive, Box, Notion, GitHub and YouTube
- Up to 4,000 GPT-4.1-mini messages or 400 GPT-4.1 messages a month on Starter
- Human support on any plan: visitors can ask for a person and the AI stops answering
- 95+ languages
- Monthly auto refresh, a weekly email digest of unanswered questions, and chat integrations for Slack, Crisp and others from Growth
Pros
- Answers from a full help center, not a short FAQ list
- No migration: point it at the knowledge base you already publish
- One flat price per year, not per agent or per resolution
Cons
- No free plan. The 7-day trial requires a credit card.
- Starter has 1 member, 10 files, manual refresh and basic analytics
- No chat integrations on Starter
- No Intercom or HubSpot integration today
Pricing
Plan | Billed monthly | Billed yearly | Messages a month | Pages |
$59 a month | $39 a month ($468 a year) | 4,000 GPT-4.1-mini or 400 GPT-4.1 | 1,000 | |
$129 a month | $79 a month ($948 a year) | 10,000 GPT-4.1-mini or 1,000 GPT-4.1 | 10,000 | |
$429 a month | $259 a month ($3,108 a year) | 40,000 GPT-4.1-mini or 4,000 GPT-4.1 | 50,000 | |
Custom | Custom | Custom | Custom |
Extra packs of 5,000 messages cost $59 a month billed monthly, or $39 a month billed yearly.
Rating: 4.9 out of 5 from 12 reviews on G2.
Best for: teams that have outgrown a free AI cap and want a whole knowledge base answered for a fixed yearly price.
4. Help Scout: best for teams whose knowledge base is Help Scout Docs
Help Scout is a shared inbox with Docs, its knowledge base product. The Free plan includes 1 Docs site for up to 5 users. Envoy, the AI chatbot that answers from Docs content and custom sources, starts on the Standard plan.
Key features
- Free plan with 5 users, 1 inbox and 1 Docs site
- Envoy chatbot at $0.75 per resolution on Standard, Plus and Pro
- A 3-month trial of unlimited AI Answers resolutions for new accounts
- A monthly spending cap on AI resolutions
Pros
- The knowledge base and the chatbot live in one tool
- You pay only when the AI resolves a conversation without help
- A conversation where the customer asks for more help is not charged
Cons
- No AI chatbot on the Free plan
- Cost grows with every resolution, so a busy month costs more
- Per-user seat price on top of resolutions
Pricing
Plan | Per user a month, billed yearly | Envoy chatbot |
Free | $0 | Not included |
Standard | $25 | $0.75 per resolution |
Plus | $45 | $0.75 per resolution |
Pro | $75 (minimum 10 users) | $0.75 per resolution |
Rating: 4.4 out of 5 from 431 reviews on G2.
Best for: small teams that already write their help center in Help Scout Docs and prefer to pay per AI answer.
How much does a chatbot on a knowledge base cost per year?
A chatbot on an existing knowledge base costs $0 a year on a free plan and $390 to $1,800 a year for the first paid AI step, billed yearly. The free plans stop at 50 to 100 AI conversations.
Route | Per month | Per year | What the year buys | Cost per AI unit |
Tidio Free | $0 | $0 | 50 Lyro conversations, one time | $0 |
Botpress Free | $0 | $0 | 100 conversations | $0 |
Tidio Lyro | $32.50 billed yearly | $390 | 600 Lyro conversations (50 a month) | $0.65 per AI conversation |
$39 billed yearly | $468 | Up to 4,000 GPT-4.1-mini messages a month, 1,000 pages | Flat price, not per conversation | |
Help Scout Standard, 1 user, 100 resolutions a month | $100 | $1,200 | 1 seat plus 1,200 AI resolutions | $0.75 per resolution plus the seat |
Botpress Plus | $150 billed yearly | $1,800 | 3,000 conversations (250 a month) | $0.60 per conversation |
Three results stand out in the math:
- Tidio is cheapest at low volume. $390 a year covers 600 AI conversations. More volume moves you to a larger Lyro tier.
- SiteGPT is a flat $468 a year. The price does not rise with each answer inside the 4,000-message monthly quota, and it is $78 more than Tidio's entry Lyro tier.
- Help Scout scales with resolutions. At 300 resolutions a month, 1 Standard seat plus $2,700 of resolutions costs $3,000 a year.
Monthly billing costs more on every paid route. SiteGPT Starter is $708 a year billed monthly and $468 billed yearly, a $240 (34%) difference. Tidio Lyro is $468 a year billed monthly and $390 billed yearly, a $78 (17%) difference. The full chatbot cost guide adds build time and hidden costs to these figures.
Can you build a free knowledge base chatbot yourself?
You can build a knowledge base chatbot yourself on an LLM API, and the usage cost per answer is the lowest of any route. The developer time to build, host and maintain it is the largest cost.
A DIY build fits teams that want the chatbot inside their own product and already have engineers. The guide to building an FAQ chatbot walks through the API route step by step. Whichever route you choose, grounding answers in your articles lowers the rate of invented answers but does not remove it, and the guide to chatbot hallucinations covers the guardrails.
How to choose a free or low-cost knowledge base chatbot
To choose, start with your monthly AI volume, then decide whether anyone can build a bot, then check where the knowledge base lives.
If you need... | Pick... | Why |
To test AI answers on a short FAQ for $0 | Tidio Free | 50 Lyro conversations, one time, with no card for the trial |
The largest free allowance and you can build | Botpress Free | 100 conversations, 3 seats and 100MB of knowledge storage |
The lowest paid AI step for a small site | Tidio Lyro | $390 a year billed yearly for 50 AI conversations a month |
A whole help center, files or drives answered with no code | $468 a year billed yearly for up to 1,000 pages | |
A chatbot on Help Scout Docs | Help Scout Standard | $0.75 per resolution on the same tool as the knowledge base |
A chatbot inside your own app | A DIY build on an LLM API | Lowest usage cost if engineers are already on staff |
How to put a chatbot on your existing knowledge base
Putting a chatbot on an existing knowledge base takes five steps on any of these tools.
- List the questions customers ask most. Pull them from your inbox, live chat history or site search.
- Check that an article answers each one. A chatbot only knows what the knowledge base says, so missing articles become wrong or empty answers.
- Connect the source. Upload the FAQ, add the help center URL or sitemap, or connect the drive where the docs live.
- Test with real questions before launch. Ask the 20 most common questions and read every answer.
- Turn on the route to a person. Then review unanswered questions each week and write the missing articles.
Technical teams with developer docs can compare dedicated options in the guide to AI chatbots for documentation. Teams that have no knowledge base yet should pick one first, using the knowledge base software comparison.
Use-case cheat sheet
Scenario | Pick | Why |
Side project with 20 FAQs and little traffic | Tidio Free | 50 free AI conversations to test with |
Developer building a prototype support agent | Botpress Free | 100 conversations and full control of the logic |
Small online store that also needs live chat | Tidio Starter plus Lyro | Live chat, Flows and AI in one widget |
SaaS company with a 300-article help center | Up to 1,000 pages for $468 a year billed yearly | |
Docs kept in Google Drive or Notion | Connects the drive or workspace instead of copying content | |
Team already answering email in Help Scout | Help Scout Standard with Envoy | Docs, inbox and AI answers in one tool |
Agency that needs many bots at high volume | Botpress Plus or Team | Unlimited AI agents on paid plans |
Product team that wants answers inside its own app | DIY build on an LLM API | Full control if engineers are available |
Try a chatbot on your knowledge base
Free plans are the right place to test answer quality on a short FAQ list. When the free cap runs out, SiteGPT answers from the whole knowledge base for one flat yearly price, with a route to a person on every plan. Starter costs $59 a month billed monthly, or $39 a month billed yearly, with a 7-day free trial that requires a credit card.
Frequently asked questions
Basics
What is a chatbot knowledge base?
A chatbot knowledge base is the set of articles, FAQs and documents a chatbot reads to answer questions. The chatbot retrieves the matching passage and writes an answer from it.
Can a chatbot use my existing knowledge base?
Yes. Tidio can scrape FAQs and import Zendesk articles, Help Scout Envoy reads Docs content, and SiteGPT trains on help center URLs, sitemaps, files and cloud drives.
Free plans
Is there a completely free chatbot for FAQs?
Yes, for low volume. Tidio Free includes 50 Lyro AI conversations one time, and Botpress Free includes 100 conversations. Both stop once the allowance is used.
Does SiteGPT have a free plan?
No. SiteGPT offers a 7-day free trial that requires a credit card. Starter costs $59 a month billed monthly, or $39 a month billed yearly.
Cost
How much does a knowledge base chatbot cost per year?
The first paid AI step costs $390 to $1,800 a year billed yearly among the tools in this guide. Tidio Lyro is $390, SiteGPT Starter is $468, Help Scout with 100 resolutions a month is about $1,200, and Botpress Plus is $1,800.
Is pay-per-resolution cheaper than a flat plan?
Pay-per-resolution is cheaper at low volume. At $0.75 per resolution, 52 resolutions a month cost $468 a year, the price of SiteGPT Starter billed yearly, before the Help Scout seat.
Setup and accuracy
How long does it take to set up a knowledge base chatbot?
A no-code tool needs no build. You connect the source, test the top questions and publish the widget. A Botpress or API build takes longer because someone has to design and maintain the agent.
Will a knowledge base chatbot make up answers?
It can. Grounding answers in your articles lowers the risk, and a route to a person catches the rest. Keep articles current, because the chatbot repeats whatever the knowledge base says.
Sources
- Checked on 22 October 2026.
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