External Data Source
An External Data Source in Salesforce is a configuration record that defines how the platform connects to data living outside Salesforce: a SQL database, a SharePoint site, an OData service, an Oracle ERP, an S3 bucket, or any system that Salesforce Connect or Files Connect can talk to.
Definition
An External Data Source in Salesforce is a configuration record that defines how the platform connects to data living outside Salesforce: a SQL database, a SharePoint site, an OData service, an Oracle ERP, an S3 bucket, or any system that Salesforce Connect or Files Connect can talk to. Each External Data Source captures the endpoint URL, authentication method, and protocol details. Once defined, the platform can query the source live (Salesforce Connect) or surface its files in Salesforce (Files Connect), without copying the data into Salesforce records.
External Data Sources are how Salesforce stays the system of engagement without being the system of record for everything. The customer's ERP holds invoices; the CRM holds opportunities and accounts; an External Data Source bridges the two so a Salesforce user sees invoice data inline on the Account record without ETL. Authentication patterns include OAuth, Named Credentials, Per-User basic auth, and Anonymous (for public OData services). The configuration lives in Setup, then External Data Sources.
How External Data Sources work in Salesforce
Salesforce Connect versus Files Connect
Two products consume External Data Sources. Salesforce Connect uses them to surface external records as External Objects with the __x suffix; the records look like normal Salesforce objects but the data lives in the external system. Files Connect uses them to surface files from SharePoint, Google Drive, OneDrive, or Box in the Salesforce Files UI. The same External Data Source configuration can serve both, depending on the protocol.
Supported protocols
External Data Sources support OData 2.0, OData 4.0, Salesforce-to-Salesforce (cross-org connect), and custom Apex adapters. OData is the standard for modern systems; the custom Apex adapter lets developers connect to any system reachable via REST. Files Connect supports SharePoint Online, OneDrive, Google Drive, Box, and a few others through pre-built adapters.
Authentication models
Five authentication patterns: Anonymous (no credentials), Named Principal (one set of credentials for all users), Per User (each Salesforce user has their own credentials), OAuth 2.0 (each user authenticates the first time, refresh tokens after), and Named Credential (Salesforce-managed credentials with named-endpoint URLs). OAuth and Named Credential are the most common in production; Per User is rare and operationally painful.
External Objects and live queries
When you create External Objects from an External Data Source, the platform generates one Salesforce-visible object per source table. SOQL queries against these objects translate to OData calls at runtime. The result: a Salesforce report can show real-time data from the external system. Limitations apply: query performance depends on the external system, and operations like roll-up summaries on External Objects are limited.
Caching and the offline option
Salesforce Connect supports two caching modes: no cache (every query hits the external system) and cached (Salesforce caches results for up to 24 hours). Caching trades freshness for performance; for slowly-changing data like product catalogs, caching is the right choice. For real-time financial data, no cache is the better fit.
Limits and the licensing constraint
Salesforce Connect is licensed by the number of external objects and the number of users with access. Standard editions get limited External Data Sources; Enterprise and above unlock more capacity. Per-call API limits apply to External Object queries; the limits are higher than internal SOQL but still a constraint at high scale. Plan licensing carefully before designing around External Data Sources.
Files Connect and external file surfacing
Files Connect uses External Data Sources to surface files from SharePoint, OneDrive, Google Drive, and Box inside Salesforce. Users see external files in the Files tab alongside native Salesforce files; they can attach them to records, share, and comment without ever leaving Salesforce. The underlying files stay in their source system; Files Connect is a pointer, not a copy.
How to create an External Data Source connection
Creating an External Data Source is a Setup task that takes about 15 minutes for OData services and longer for custom Apex adapters. The configuration includes endpoint, authentication, and protocol options.
- Open External Data Sources in Setup
Setup, then External Data Sources. Click New External Data Source. The configuration page opens.
- Provide name and type
Name the source (Acme_ERP, SharePoint_Documents). Pick the Type: Salesforce Connect OData 2.0/4.0, Salesforce-to-Salesforce, Files Connect, or Apex Connector.
- Configure the endpoint URL
For OData: the service root URL. For Files Connect: the SharePoint/OneDrive/Google Drive endpoint. For Salesforce-to-Salesforce: the target org login URL.
- Pick the authentication method
Anonymous, Named Principal, Per User, OAuth 2.0, or Named Credential. Configure the credentials per the selection.
- Save and validate
Click Save. The platform tests the connection. If validation succeeds, the data source is available. If it fails, check the endpoint URL and credentials.
- Sync external objects (Salesforce Connect)
For Salesforce Connect data sources, click Validate and Sync. Pick which tables to surface as External Objects. The platform creates one __x object per selected table.
Internal label for the data source. Used in Setup and in External Object configuration.
Protocol: OData 2.0, OData 4.0, Salesforce-to-Salesforce, Files Connect, or Apex Connector.
The endpoint of the external system. Service root for OData, login URL for Salesforce-to-Salesforce.
The credential model used to connect.
- Per User authentication is operationally painful. Each user must enter their own credentials the first time they use the source. Use OAuth or Named Credential instead.
- External Object queries cost per call. Heavy reporting can hit the external system''s rate limits; cache aggressively for read-heavy patterns.
- Salesforce Connect license capacity matters. Each external object counts against the org''s entitlement; plan licensing before designing around it.
- Files Connect surfaces metadata but not full-text content for search. Searching inside the file requires the source system''s search capability or a separate full-text index in Salesforce.
Trust & references
Straight from the source - Salesforce's reference material on External Data Source.
- Salesforce ConnectSalesforce Help
- Files ConnectSalesforce Help
About the Author
Dipojjal Chakrabarti is a B2C Solution Architect with 29 Salesforce certifications and over 13 years in the Salesforce ecosystem. He runs salesforcedictionary.com to help admins, developers, architects, and cert/interview candidates sharpen their fundamentals. More about Dipojjal.
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