wardawgmalvicious Fabric authentication & token audiences
All Fabric operations require Microsoft Entra ID OAuth 2.0 bearer tokens. Using the wrong audience is the #1 cause of 401 errors.
| Access Target | Token Audience / Scope |
|---|---|
| Fabric REST API | https://api.fabric.microsoft.com/.default |
| Power BI REST API (refresh, data sources, permissions, DAX) | https://analysis.windows.net/powerbi/api/.default |
| OneLake (DFS/Blob) | https://storage.azure.com/.default |
| Warehouse / SQL Endpoint / SQL Database (TDS) | https://database.windows.net/.default |
| KQL / Kusto | https://kusto.kusto.windows.net/.default |
| XMLA Endpoint | https://analysis.windows.net/powerbi/api/.default |
| Azure Resource Management | https://management.azure.com/.default |
az login
az account get-access-token --resource https://api.fabric.microsoft.com # Fabric REST
az account get-access-token --resource https://database.windows.net # SQL / TDS
az account get-access-token --resource https://analysis.windows.net/powerbi/api # Power BI
Critical: OneLake ONLY accepts https://storage.azure.com/.default — using https://datalake.azure.net/ will fail.
az login flow variants
az login --allow-no-subscriptions --tenant <tid> # Fabric tenant with no Azure subscription
az login --use-device-code --tenant <tid> # headless / SSH / no-browser
az login --service-principal -u <appId> -p <secret> --tenant <tid> # CI/CD with SPN secret
az login --service-principal -u <appId> --certificate /path/cert.pem --tenant <tid> # SPN cert (preferred — no secret to rotate)
az login --identity # system-assigned managed identity
az login --identity --username <clientId> # user-assigned managed identity
Without --allow-no-subscriptions, Fabric-only tenants (no Azure subscription attached) get a confusing "No subscriptions found" error before any Fabric call runs.
az rest --resource requirement
api.fabric.microsoft.com is not a built-in Azure cloud endpoint, so az rest cannot derive the audience from the URL. Always pass --resource:
az rest --method get \
--resource "https://api.fabric.microsoft.com" \
--url "https://api.fabric.microsoft.com/v1/workspaces"
Without --resource, you get "Can't derive appropriate Azure AD resource from --url" — the single most common az rest Fabric error.
Decoding a token to debug 401s
When you get an unexpected 401, decode the JWT to see what audience the token actually has:
TOKEN=$(az account get-access-token --resource https://api.fabric.microsoft.com --query accessToken -o tsv)
echo "$TOKEN" | cut -d'.' -f2 | base64 -d 2>/dev/null | jq .
Compare the aud claim against the table above. Other useful claims: exp (Unix expiry), oid (principal object ID), tid (tenant ID).
TDS connection essentials (Warehouse / SQL Database)
When connecting via sqlcmd, ODBC drivers, or any TDS client:
| Parameter | Value |
|---|---|
| Port | 1433 (TCP, must be open outbound) |
Initial Catalog / Database |
Item display name (NOT the FQDN) |
| Authentication | Microsoft Entra ID only — SQL auth is not supported |
| Encryption | Encrypt=Yes required |
| Token audience | https://database.windows.net/.default |
| MARS | Not supported — remove MultipleActiveResultSets from connection strings (or set to false) |
Gotcha: Login failed... database not found usually means the connection string passed the FQDN as Initial Catalog instead of the workspace item display name. Allow *.datawarehouse.fabric.microsoft.com and *-pbidedicated.windows.net through any outbound firewall.
Reference
- Microsoft Learn: Authenticate to Azure using Azure CLI
- Microsoft Learn: MSAL overview
- Microsoft Learn: Microsoft Entra authentication for Fabric SQL
- Comprehensive MS Learn link bundle (concept / Fabric REST auth / Azure CLI / OAuth flows / MSAL by language / SPN & managed identity / scopes & claims / Fabric-specific): references/REFERENCE.md