Canvas App Previewer
Canvas App Previewer is a Setup tool that allows administrators and developers to preview Canvas apps directly within Salesforce.
Definition
Canvas App Previewer is a Setup tool that allows administrators and developers to preview Canvas apps directly within Salesforce. Canvas apps are web applications hosted outside of Salesforce that are displayed within the Salesforce UI using an iframe. The previewer lets users test how these external apps render before deploying them to production.
In plain English
“Here's a simple way to think about it: Canvas App Previewer is the test bench for embedded apps. Before you put a third-party web app inside Salesforce in front of users, you preview it here to catch the failures (broken auth, wrong sizing, CSP blocks) that happen only in the embedded context.”
Worked example
A developer at Apex Dynamics builds a Canvas app that displays real-time inventory data from an external warehouse system. Using the Canvas App Previewer, she tests how the app renders inside the Salesforce Account page layout, verifies that the authentication flow works correctly, and checks that the iframe resizes properly on different screen sizes.
Why Canvas App Previewer lets you test embedded apps without leaving Salesforce
A Canvas app is a web application hosted somewhere outside Salesforce - your own infrastructure, a vendor's platform, an internal tool - that gets embedded inside Salesforce in an iframe. Canvas App Previewer is the Setup tool that lets you preview how a Canvas app renders inside the Salesforce shell before deploying it for users. Authentication, sizing, signed-request handling all get tested in a controlled environment.
The reason this preview surface earns its place is that Canvas apps fail in distinctive ways: signed-request authentication that works on the developer's machine but fails in production, iframe sizing that looks fine in isolation but breaks the surrounding Salesforce layout, content security policy violations that only surface inside the platform. Catching these before users see them is the whole job of the previewer.
How organizations use Canvas App Previewer
Developers caught a signed-request auth failure in the previewer before deploy - the bug only surfaced inside Salesforce's iframe context, not in standalone testing.
QA validates every Canvas App update through the previewer; the iframe-specific edge cases would otherwise reach production undetected.
Vendor demos use the previewer to evaluate AppExchange Canvas apps in the org's actual environment, not the vendor's clean demo org.
Trust & references
Straight from the source - Salesforce's reference material on Canvas App Previewer.
- Canvas App PreviewerSalesforce Help
- Expose Your Connected App as a Canvas AppSalesforce Help
Test your knowledge
Q1. Who can benefit from understanding Canvas App Previewer?
Q2. What architecture concept is Canvas App Previewer an example of?
Q3. How does Salesforce's multi-tenant model affect Canvas App Previewer?
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