Langgraph deployment with langchain API key?

Product Help LangGraph Platform
,
1

Hi there,

I’ve created a deployment of an agentic framework on langsmith (which runs all fine in studio). I now have my API URL to send api requests to in an external chat application.

Alongside, I need a langchain api key.

Workspace in which I deployed → settings → API key

personal: lsv2_pt_2…e763
OR
service key: lsv2_sk_2…c924

However None of these API keys actually work for my external application:

curl -s -X GET -H "x-api-key: lsv2_sk_***924" https://na*****us.langgraph.app/health -w "\nStatus:%{http_code}\n" -o /dev/stdout

and I get “Status:404” errors.

All LLM models keep insisting I create a new langchain api key

“”"
That response comes from the LangGraph gateway when the token is a valid LangSmith key but not authorised for the Threads APIs. Key types, verified against the gateway’s rules:

Prefix Purpose Works for /threads/*
lsv2_pt_* Personal tracing key 404 Not Found
lsv2_sk_* Service/tracing key 404 Not Found
sk-* Single-tenant deployment key :check_mark: (200)
dep-srv-* Multi-tenant deployment key :check_mark: (200)

The service key (lsv2_sk_*) can read the OpenAPI spec but is blocked from state-persisting endpoints such as Threads / Runs / Store.
“”"

I could not resolve this!
Any insights are very welcome!

Cheers,
Jasper

2

Hi Jasper, do you have any custom authentication setup? If so you may need to include additional headers etc to satisfy auth. Also our deployments don’t have any method like /health which may be why you are seeing a 404.

3

Thanks Mukil,

I moved to the API studio to test my curl commands. Eventually the curl command below no longer gave 404 errors and it worked. In truth, I’m not sure what changed in the deployment. Perhaps, like you suggest, there was some authentication imposed in the deployment somehow.

curl https://na***1.us.langgraph.app/threads/search \
  --request POST \
  --header 'Content-Type: application/json' \
  -H 'x-api-key: lsv2_pt_4c***28' \
  --data '{
  "metadata": {},
  "values": {},
  "status": "idle",
  "limit": 10,
  "offset": 0,
  "sort_by": "thread_id",
  "sort_order": "asc"
}'

all resolved now.