Integration: Chainlit
Use Chainlit UI for your Haystack apps through Hayhooks
Table of Contents
Overview
Chainlit is an open-source Python package for building production-ready Conversational AI. By exposing your Haystack app (standalone agent or pipeline) through Hayhooks as OpenAI-compatible endpoints, you can run the Chainlit chat UI inside your Hayhooks server, giving you a zero-configuration frontend to interact with your deployed pipelines without a separate client.
For full details, see the Hayhooks Chainlit integration guide.
Installation
Install Hayhooks with the chainlit extra:
pip install "hayhooks[chainlit]"
Usage
Hayhooks Quick Start
The simplest way to enable the Chainlit UI is via the --with-chainlit flag:
hayhooks run --with-chainlit
This starts Hayhooks with the embedded Chainlit UI available at http://localhost:1416/ chat.
Create a Pipeline Wrapper
# pipelines/my_chat/pipeline_wrapper.py
from typing import Generator
from haystack import Pipeline
from haystack.components.builders import ChatPromptBuilder
from haystack.components.generators.chat import OpenAIChatGenerator
from haystack.dataclasses import ChatMessage
from hayhooks import BasePipelineWrapper, streaming_generator
class PipelineWrapper(BasePipelineWrapper):
def setup(self) -> None:
self.system_message = ChatMessage.from_system("You are a helpful assistant.")
chat_prompt_builder = ChatPromptBuilder()
llm = OpenAIChatGenerator(model="gpt-4o-mini")
self.pipeline = Pipeline()
self.pipeline.add_component("chat_prompt_builder", chat_prompt_builder)
self.pipeline.add_component("llm", llm)
self.pipeline.connect("chat_prompt_builder.prompt", "llm.messages")
def run_chat_completion(self, model: str, messages: list[dict], body: dict) -> Generator:
chat_messages = [self.system_message] + [
ChatMessage.from_openai_dict_format(msg) for msg in messages
]
return streaming_generator(
pipeline=self.pipeline,
pipeline_run_args={"chat_prompt_builder": {"template": chat_messages}},
)
Pipelines must support chat completion (e.g. using streaming_generator or async_streaming_generator). See
OpenAI compatibility and the
pipeline examples for implementation details.
Run Hayhooks with UI
hayhooks run --with-chainlit --pipelines-dir ./pipelines
Navigate to
http://localhost:1416/chat in your browser. You’ll see your deployed pipeline and can start chatting!
Examples
Learn how to build an end-to-end agent example with Haystack, Hayhooks and Chainlit in Chainlit Weather Agent Example
License
hayhooks and chainlit are distributed under the terms of the
Apache-2.0 license.