topic Re: Databricks Apps with FastAPI in Administration & Architecture

Databricks Apps with FastAPI

AndyK — Thu, 19 Jun 2025 08:38:35 GMT

I have a FastAPI Databricks App deployed to a hosted workspace. How can I call the API from external tools like Postman?

P.S. I was able to call the API within the same browser.

Re: Databricks Apps with FastAPI

SP_6721 — Fri, 20 Jun 2025 09:40:35 GMT

Hi @AndyK ,

External tools don’t share browser’s login context, so you’ll need to add a bearer token in the Authorization header manually.

Start by generating an access token. You can either use the Databricks CLI (databricks auth token) to get an OAuth token, or create a Personal Access Token (PAT) from your workspace settings.
Then in Postman, enter your API endpoint like:
https://<workspace-host>/api/<endpoint-path>
Go to the Authorization tab, choose Bearer Token, and paste your token.

Make sure you have CAN USE permission on the Databricks App. Also, note that tokens,especially OAuth, can expire (usually in about an hour), so you might need to generate new one when needed

Re: Databricks Apps with FastAPI

AndyK — Sat, 05 Jul 2025 01:22:05 GMT

Hi,

PAT doesn't seem to work, but we use a workspace token and it was able to go through. Thanks

Re: Databricks Apps with FastAPI

Gareema — Sun, 20 Jul 2025 15:33:25 GMT

What do you mean by workspace token? Can you elaborate a little?

Re: Databricks Apps with FastAPI

Gareema — Sun, 20 Jul 2025 15:35:44 GMT

How to generate one?

Re: Databricks Apps with FastAPI

Gareema — Sun, 20 Jul 2025 16:09:01 GMT

I tried generating, the token this for service principle:

export CLIENT_ID=<client-id>
export CLIENT_SECRET=<client-secret>

curl --request POST \
--url <token-endpoint-URL> \
--user "$CLIENT_ID:$CLIENT_SECRET" \
--data 'grant_type=client_credentials&scope=all-apis'

It did generates a token, but that token still doesn't work with the Databricks App i created.
I am just passing it like:

response = requests.get(
"https://<app specific url>.azure.databricksapps.com/api/v1/table",
headers={"Authorization": f"Bearer {token} "})
print(response.json())

Re: Databricks Apps with FastAPI

AndyK — Mon, 21 Jul 2025 08:39:40 GMT

Hi,

Make sure your token endpoint url is like this: https://<databricks-instance>/oidc/v1/token.

Refer here for workspace-level access token: https://docs.databricks.com/aws/en/dev-tools/auth/oauth-m2m

Also make sure you have granted access of the service principal to the app: https://apps-cookbook.dev/docs/fastapi/getting_started/connections/connect_from_app