Open source chatbots are reshaping how we build conversational user interfaces with flexibility, privacy, and robust community support. By 2030, the global chatbot market is projected to reach $27.29 billion, growing at a CAGR of 23.3% from 2025 to 2030.
Whether you’re exploring an AI chatbot framework or designing natural language understanding flows, this guide highlights 11 standout open-source platforms for building conversational agents.
Start Building Your Chatbot in Minutes. No Code & Low Cost
Launch AI-powered conversations on WhatsApp, Instagram, and more with ControlHippo’s free-forever plan.
Before we start, let’s take a step back. Yes, building a chatbot from scratch with open-source frameworks has its advantages — full control, customization, and flexibility. But let’s be real: not every business owner has the time or technical expertise to code and maintain one.
That’s why chatbot platforms exist. They take away the complexity and let you create smart bots through a simple drag-and-drop builder. No coding, no steep learning curve.
Before we move on to the best open-source chatbot frameworks, here’s a third-party chatbot provider with a free-forever plan, ControlHippo:
ControlHippo is a powerful chatbot builder platform. It lets marketers and small business owners build AI chatbots easily, no coding needed. The visual conversation builder is intuitive and you can build smart conversational agents with it.
ControlHippo helps connect with multiple messaging platforms on a single dashboard making it the most demanded omnichannel platform in the market. This makes it valuable for marketers looking to reach customers on the channels they already use. Unlike open-source frameworks, no developers are needed. It offers a free forever plan.
Here is the List of Top Open Source Chatbots in 2025
We’ve curated a list of top open source chatbot providers in 2025. This tools have been selected after analyzing the reviews of customer on various listing platforms like G2, capterra, and getapp.
We’ve also analyzed the key features that a user generally assess while making the purchase descision
| Chatbot Platform | Best For | Pricing Range | Key Features | Technical Skill Required |
|---|---|---|---|---|
| Rasa | Custom, privacy-focused AI bots | Contact sales | Full dialogue control, self-hosted, NLP capabilities | Advanced (Developer skills needed) |
| Botpress | No-code, flexible, multi-platform | $0 + AI spend to $2000/mo | Visual builder, live agent handoff, multi-channel | Beginner to Intermediate |
| ChatterBot | Beginners, rapid prototyping | Contact sales | Python-based, machine learning, simple datasets | Basic Python knowledge |
| DeepPavlov | Advanced NLP & research use | Contact sales | Pretrained NLU models, multi-language support | Advanced NLP knowledge |
| Microsoft Bot Framework | Enterprise cross-channel bots | Contact sales | Visual designer, multi-channel deployment, Azure integration | Intermediate to Advanced |
| Tock | Complex, multi-channel bots | $79 - $769/mo | Policy-driven dialogue, analytics, API access | Intermediate to Advanced |
| OpenDialog | Context-aware, role-driven bots | Contact sales | Visual builder, multi-channel support, AI co-pilot | Intermediate |
| Alan AI | Voice-first conversational bots | Contact sales | Voice SDKs, offline voice processing | Intermediate |
| Rocket.Chat Chatbot | Embedded chatbot in Rocket.Chat | Free - $4/user/mo | Real-time messaging, modular NLU, video integration | Intermediate |
| Kuki AI (Pandorabots) | Rule-based, AIML scripting | Free - $5000/yr | AIML scripting, multi-language, ChatGPT integration | Basic scripting |
| Program AB | Lightweight, offline text bots | Contact sales | AIML 2.0 interpreter, low-code graphical interface | Developer (Java knowledge) |
1. Rasa
Rasa is a comprehensive open-source AI chatbot and AI chatbot framework focused on flexibility and privacy. It is ideal for custom pipelines and complex use cases, Rasa offers developer-first tools and top-tier natural language processing capabilities.
Features
- Enterprise search
- Contextual response rephrase
- Custom actions server
- Channel connectors
- End-to-end tester
Pros
- Highly customizable with full dialogue-control framework
- Strong community support and plugin marketplace
- Self-hosted options ensure complete data privacy
Cons
- Requires technical setup and developer expertise
- Maintenance of infrastructure can be challenging
- Initial configuration is steeper for non-developers
Pricing
- Contact sales for pricing
- Over 2.5 billion working hours are expected to be saved by chatbots by 2025.
2. Botpress
Botpress is a powerful open-source chatbot framework designed for building conversational agents using a no-code approach. Its visual conversation builder enables teams to design, deploy, and manage chatbots without writing complex code.
Ideal for both developers and non-technical users, Botpress supports natural language understanding and integrates easily with multiple messaging platforms like WhatsApp, Slack, and Microsoft Teams. It’s also framework agnostic, giving teams the flexibility to plug it into different backend systems and messaging apps without heavy rewrites. This makes it one of the most flexible open-source chat platforms today.
Features
- Visual building studio
- Live agent handoff
- Live-chat support
- Whiteglove onboarding
- Dedicated support manager
Pros
- Intuitive flows via visual conversation builder
- Modular architecture simplifies customization
- Active user community for templates
Cons
- Some enterprise features require manual setup
- Plugin quality can be inconsistent
- Scaling across servers needs extra orchestration
Pricing
- Pay-as-you-go: $0 + AI spend per month
- Plus: $89 + AI spend per month
- Team: $495 + AI spend per month
- Enterprise: $2000 per month
3. ChatterBot
ChatterBot is a Python-based open-source chatbot framework ideal for beginners and rapid prototyping. It allows developers to train chatbots using custom datasets, making it perfect for building simple conversational agents. With built-in machine learning capabilities, ChatterBot learns from past conversations to improve over time. It’s a great choice for those exploring open-source AI chatbot tools for lightweight use cases and educational purposes.
Features
- Chat history
- Bot personas
- Import your data
- No-code platform
- Multilingual
Pros
- Quick to launch simple chatbots in Python
- Train on custom question–answer data
- Minimal dependencies for lightweight deployments
Cons
- Limited natural language understanding depth
- Not built for multi-turn, contextual dialogues
- Less maintained with a smaller dev community
Pricing
- Contact sales for pricing
4. DeepPavlov
DeepPavlov is an advanced open-source chatbot platform built for tasks requiring strong natural language processing and natural language understanding. It comes equipped with pre-trained models for question answering, intent recognition, and multi-language support.
Ideal for research and enterprise applications, this open-source AI chatbot toolkit helps developers build intelligent, context-aware conversational agents that can operate in diverse real-world scenarios.
Features
- Multi-skill dialogue management
- Common NLU components
- Dialog orchastration
- Neural architecture search
- Model with memory
Pros
- High-quality natural language processing models
- Prebuilt components speed up development
- Works across languages out of the box
Cons
- Heavy on resource requirements
- Customisation requires NLP know-how
- No GUI-based layout for dialogue flow
Pricing
- Contact sales for pricing
5. Microsoft Bot Framework
Microsoft Bot Framework is a robust open-source chatbot framework that supports building, testing, and deploying AI-powered conversational agents. It is used across multiple messaging services like Skype, Teams, and Facebook Messenger. With SDKs in C# and JavaScript, it integrates seamlessly with Azure services, enabling scalable bot development.
It also offers tools for natural language understanding, conversation management, and multi-channel deployment, making it a reliable choice for enterprises looking to build intelligent, cross-platform open source chatbots.
Features
- Visual designer
- Emulator
- Web chat control
- Multi channel deployment
- Dialog management
Pros
- First-class enterprise-level debugging and logging
- Official connectors to major messaging channels
- Visual Composer tool aids non-coders
Cons
- Some parts are tied to Azure Cloud
- Significant learning curve for Composer & SDK
- Operational costs if using Azure services
Pricing
- Contact sales for pricing
6. Tock
Tock is a versatile open-source chatbot framework designed for building complex, multi-channel conversational agents with ease. It supports policy-driven dialogue management, rich analytics, and seamless integration with web, mobile, and voice platforms.
Ideal for enterprises, Tock enables the creation of scalable conversational user interfaces while offering tools for monitoring performance and optimising user interactions. It’s a strong choice for those building structured, context-aware chatbots.
Features
- Walk-in waitlist tools
- Table and guest management
- 2-way SMS communications
- Pos integrations
- API access & webhooks
Pros
- Ideal for branching, context-rich conversations
- Built-in metrics for continuous improvement
- Deploys via API to web, mobile, voice
Cons
- Smaller open-source ecosystem
- Requires dialogue graph modelling know-how
- Less flexible NLU without external tools
Pricing
- Base: $79 per month
- Essential: $199 per month
- Premium: $399 per month
- Premium unlimited: $769 per month
- Businesses using chatbots save roughly 30% in support costs, totalling nearly $8 billion annually.
7. OpenDialog
OpenDialog is a dialogue-first open source platform focused on building context-aware, role-driven conversational agents. It allows teams to design rich conversational user interfaces using a visual conversation builder, enabling non-developers to map complex user journeys with ease.
With a strong emphasis on context and conversational logic, OpenDialog is ideal for businesses aiming to deliver highly personalised and structured chatbot experiences using an extensible open-source chatbot framework.
Features
- Unlimited AI Agents and work tasks
- 2GB of analytics data
- Multi-channel support
- Digital concierge
- AI co-pilot
Pros
- Design context-aware conversational user journeys
- Visual UI makes storyline crafting easier
- Clear documentation with enterprise readiness
Cons
- Relies on external NLU integration
- The policy model is sophisticated, needs learning
- Niche community, fewer third-party plugins
Pricing
- Contact sales for pricing
8. Alan AI
Alan AI is a voice-centric open-source AI chatbot platform designed to create natural and seamless conversational audio user interfaces. It offers SDKs for easy integration into mobile and web apps, enabling developers to build voice-enabled conversational agents with minimal coding.
Focused on speech recognition and offline voice processing, Alan AI is perfect for projects prioritising voice-first interactions within an open-source chatbot framework.
Features
- Model of constraints
- Data crawling
- Single code space
- Tunable reasoning
- Customize UI
Pros
- Voice-first agent: speech is the primary interface
- Quick integration with minimal coding
- Offline support enhances privacy
Cons
- Not focused on text-based bots
- Small open source footprint
- Less community-driven content
Pricing
- Contact sales for pricing
9. Rocket.Chat Chatbot
Rocket.Chat Chatbot is an embedded open-source chatbot framework integrated within the Rocket.Chat messaging platform. It enables users to build and deploy conversational agents directly inside the chat environment, supporting real-time messaging and multi-tenant setups.
With support for various NLU (Natural Language Understanding) integrations and a strong community support system, this platform is ideal for teams already using Rocket.Chat.
Features
- Self manages to host only
- Advanced hosting options
- Unlimited chat and file history
- Video conferencing integration
- Content moderation
Pros
- Seamlessly integrates with Rocket.Chat
- Supports modular NLU choices
- Community-backed with a robust plugin ecosystem
Cons
- Limited to Rocket.Chat environment
- Not tailored for broader multichannel needs
- Lacks visual tools for flow building
Pricing
- Starter: $0 per user per month
- Pro: $4 per user per month
- Enterprise: Contact sales
10. Kuki AI (Pandorabots)
Kuki AI, powered by AIML (Artificial Intelligence Markup Language) scripting, is one of the most well-known conversational agents available today. This open-source chatbot platform uses rule-based logic to create engaging and human-like conversations.
Kuki AI is Ideal for those interested in traditional chatbot design. It offers extensive customisation through AIML, making it a popular choice for developers exploring building conversational user interfaces.
Features
- ChatGPT integration
- Configure AI bot personality
- Unified inbox
- Multi language
- Live chat
Pros
- Long-standing AIML framework familiarity
- Centralised sandbox speeds prototyping
- Rich example bots for learning
Cons
- Static rules, limited true NLU
- Verbose AIML syntax
- Less suitable for modern NLP use cases
Pricing
- Baby plan: Free forever
- Little plan: $150 per year
- King plan: $500 per year
- Emperor plan: $5000 per year
11. Program AB
Program AB is a Java-based interpreter for AIML 2.0, making it a reliable open-source chatbot framework for creating offline, text-based conversational agents. It excels at handling scripted dialogues and is well-suited for developers who prefer working within a Java environment. Though it lacks advanced natural language understanding, Program AB remains a solid choice for lightweight chatbots built on rule-based AI.
Features
- Analyze log files
- Code addition for application-specific custom AIML tags
- Customization options
- Low-code graphical interface
- Multichannel deployment
Pros
- Robust, standard AIML interpretation
- Works without internet or cloud services
- Hands-on coding for custom logic
Cons
- Lacks ML-powered NLU capabilities
- No GUI builder—developers only
- Conversational abilities are limited to scripted content
Pricing
- Contact sales for pricing
Conclusion
From the developer-rich customisation of Rasa to the AIML simplicity of Pandorabots and the no-code convenience of ControlHippo, this curated list presents the top open-source chatbots ideal for every project type in 2025.
Whether you’re exploring open source chatbot platforms or deploying on WhatsApp, choose based on your team’s technical depth, channel needs, and growth plans. For flexibility, framework-agnostic tools like Botpress or Microsoft Bot Framework are ideal, while DeepPavlov offers a rich open-source library for advanced NLP tasks.
Yes! Options like Rasa, Botpress, DeepPavlov, Microsoft Bot Framework, Tock, OpenDialog, Alan AI, Rocket.Chat’s built-in bot, Kuki AI, and Program AB are all open source using different programming languages, offering robust tools for developing conversational agents.
An open source framework chatbot is a conversational agent whose source code is publicly available—usually under licenses like MIT, Apache, or GPL. This grants you full control over customisation, self-hosting, and expansion through community support.
Absolutely, frameworks like Rasa, Botpress, and ControlHippo include connectors or plug-ins for WhatsApp. Some require third-party services (e.g., Twilio, Meta-approved provider), while platforms like ControlHippo simplify it with built-in integration.
Updated : August 22, 2025
Jainy Patel is a content strategist who specializes in omnichannel communication solutions. She develops innovative marketing strategies that unify messaging across various channels, ensuring a consistent and engaging customer journey. Jainy is passionate about optimizing communication processes and crafting targeted content that resonates with audiences at every touchpoint.