- Force.com Canvas
- Lightning Connect
- HYPERLINK function in a formula field
Am I forgetting any other options? Please let me know!
Force.com Canvas
This is a well documented feature for which I'll summarize the key capabilities as of Summer '15:
- Authentication via signed request or OAuth 2.0
- Canvas app in Visualforce via apex:canvasApp component
- Canvas app in the Publisher as a custom action
- Canvas app in the Chatter feed as feed items
- Canvas in the Salesforce1 app via the navigation menu
Lightning Connect
Instead of feeding data back and forth with integration jobs or real-time callouts, Lightning Connect offers a speedy alternative for surfacing external data in Salesforce, using the OData protocol. Simple scenario: Data stored in an on-premise database table can be exposed with a few clicks as an object in Salesforce, that looks and feels to end users like any other standard or custom Salesforce object. No code required!
Furthermore, Summer '15 added some really cool features to Lightning Connect, such as a native Salesforce Connector and the ability to access government and health data backed by Socrata Open Data Portal™. But in my opinion Lightning Connect will become absolutely, ridiculously amazing once write capabilities (still in Pilot) become GA, along with support for Process Builder, validation rules and Apex triggers.
HYPERLINK function in a formula field
Why do I even bother mentioning this? I think simply that the cheapest, crudest means of "integrating" two systems should not be overlooked as an option. Time is money, and if an external system supports deep linking or can process redirects to specific records, using a formula field to dynamically present a clickable URL to a user can be a really quick win.