chainlit
Build Conversational AI.
Decision gist · record as of 2026-08-14
Yes, if you need to rapidly prototype or deploy a conversational AI application with a web UI and are comfortable with Python async patterns. The low install friction, active maintenance, and permissive license make it a practical choice. The large dependency footprint (24 packages) and community-maintained status (as of May 2025) are trade-offs to accept if the UI and async orchestration features justify the overhead for your use case.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.10 or later; FastAPI and uvicorn will be installed as dependencies.
- Low install friction with a pure Python wheel.
- The package has 24 runtime dependencies including FastAPI, uvicorn, and async utilities, but all are standard PyPI packages.
License · maintenance · safety
Apache-2.0 (permissive) — Apache-2.0 is permissive; you can use, modify, and distribute Chainlit in commercial applications provided you include the license notice and state significant changes.
last release 2026-04-22 (114 days) · last repo commit 2026-08-04 · 12,383 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 789,417 downloads/mo, #5,055 on PyPI
Alternatives
Verify before relying
pip install chainlit
import chainlit as cl
@cl.on_message
async def main(message: cl.Message):
await cl.Message(content="Response").send()
# Run with: chainlit run script.py- Whether the package includes built-in integrations with specific LLM providers (OpenAI, Anthropic, etc.) or requires separate setup.
- Performance characteristics under concurrent user load or message volume.
- Deployment options and hosting requirements beyond local development.
What it is and what it does
Chainlit is a Python framework that wraps FastAPI and async utilities to rapidly prototype and deploy conversational AI applications with a web-based chat UI. It handles the plumbing of message routing, async execution, and real-time bidirectional communication via WebSocket, letting you focus on the conversation logic itself.
You write Python functions decorated with Chainlit handlers (like @cl.on_message) that receive user input and send responses back to the browser. The framework manages the UI, session state, and async orchestration. It's designed for building chatbots, agents, and copilots that integrate with language models and external tools, and includes support for intermediate steps, tool calls, and streaming responses.
Use it for
- Prototype a chatbot or conversational agent that calls an LLM API and returns responses in a web UI.
- Build a multi-turn conversation system with tool use, where intermediate steps are visible to the user.
- Deploy a copilot or assistant interface that integrates with external APIs or knowledge bases.
- Create a debugging or testing interface for LLM-based workflows with step-by-step execution visibility.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes, if you need to rapidly prototype or deploy a conversational AI application with a web UI and are comfortable with Python async patterns.
The low install friction, active maintenance, and permissive license make it a practical choice. The large dependency footprint (24 packages) and community-maintained status (as of May 2025) are trade-offs to accept if the UI and async orchestration features justify the overhead for your use case.
Install
chainlit on PyPI
Before you install
Low install friction with a pure Python wheel. The package has 24 runtime dependencies including FastAPI, uvicorn, and async utilities, but all are standard PyPI packages. Maintenance is active with recent commits and community stewardship as of May 2025.
Requires Python 3.10 or later; FastAPI and uvicorn will be installed as dependencies.
License in practice
Apache-2.0 is permissive; you can use, modify, and distribute Chainlit in commercial applications provided you include the license notice and state significant changes.
Quickstart
pip install chainlit
import chainlit as cl
@cl.on_message
async def main(message: cl.Message):
await cl.Message(content="Response").send()
# Run with: chainlit run script.pyVerify before relying
- Whether the package includes built-in integrations with specific LLM providers (OpenAI, Anthropic, etc.) or requires separate setup.
- Performance characteristics under concurrent user load or message volume.
- Deployment options and hosting requirements beyond local development.
Package facts
| License | Apache-2.0 permissive |
| Python support | Supports the current Python release <3.14.0,>=3.10 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 24 packagesaiofilesasynceraudioop-ltsclickdataclasses-jsonfastapifiletypehttpxlazifyliteralaimcpnest-asynciopackagingpydantic-settingspydanticpyjwtpython-dotenvpython-multipartpython-socketiostarlettesyncertomliuvicornwatchfiles |
| Maintenance | Actively maintained 114 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 789,417 / month, #5,055 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Environment :: Web EnvironmentFramework :: FastAPIProgramming Language :: JavaScriptTopic :: Communications :: ChatTopic :: Scientific/Engineering :: Artificial IntelligenceTopic :: Software Development :: Libraries :: Python ModulesTopic :: Software Development :: User Interfaces |
Evidence: chainlit-2.11.1-py3-none-any.whl
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See also shinychat · openai-chatkit · langchain · ai-parrot · alita-sdk · rasa-sdk · langchain-cli · lunary · langchain-google-genai · copilotkit