LangChain

from opentelemetry import trace
from opentelemetry.sdk.trace import TracerProvider
from opentelemetry.sdk.resources import Resource, SERVICE_NAME
from posthog.ai.otel import PostHogSpanProcessor
from opentelemetry.instrumentation.langchain import LangchainInstrumentor
resource = Resource(attributes={
    SERVICE_NAME: "my-app",
    "posthog.distinct_id": "user_123", # optional: identifies the user in PostHog
    "foo": "bar", # custom properties are passed through
})
provider = TracerProvider(resource=resource)
provider.add_span_processor(
    PostHogSpanProcessor(
        api_key="<ph_project_token>",
        host="https://us.i.posthog.com",
    )
)
trace.set_tracer_provider(provider)
LangchainInstrumentor().instrument()

import { NodeSDK } from '@opentelemetry/sdk-node'
import { resourceFromAttributes } from '@opentelemetry/resources'
import { PostHogSpanProcessor } from '@posthog/ai/otel'
import { LangChainInstrumentation } from '@traceloop/instrumentation-langchain'
const sdk = new NodeSDK({
  resource: resourceFromAttributes({
    'service.name'

from langchain_openai import ChatOpenAI
from langchain_core.prompts import ChatPromptTemplate
prompt = ChatPromptTemplate.from_messages([
    ("system", "You are a helpful assistant."),
    ("user", "{input}")
])
model = ChatOpenAI(openai_api_key="your_openai_api_key")
chain = prompt | model
response = chain.invoke({"input": "Tell me a joke about programming"})
print(response.content)

import { ChatOpenAI } from '@langchain/openai'
import { ChatPromptTemplate } from '@langchain/core/prompts'
const prompt = ChatPromptTemplate.fromMessages([
  ["system", "You are a helpful assistant."],
  ["user", "{input}"]
])
const model = new ChatOpenAI({ apiKey: