Combined CDN bundle including core SDK, multiplexed transport and module-metadata integration

[Laura-Arcidiacono]

Problem Statement

Currently, we integrate Sentry into our web application solely through CDN scripts (not through NPM installation), loading the bundle.min.js (core SDK).
We want to enable error routing for the microfrontend, but there is no bundle to do so, and that forces us to load two additional files:
1. multiplexedtransport.min.js
2. modulemetadata.min.js

This approach works, but introduces:
• Performance concerns: three HTTP requests
• Version-management overhead
• HTML verbosity: extra tags in every page template

Solution Brainstorm

Publish an additional CDN artifact that internally includes:

• the core bundle.min.js
• transports/multiplexedtransport.js
• integrations/modulemetadataintegration.js

All in one file, exposing Sentry.makeMultiplexedTransport() and Sentry.moduleMetadataIntegration() on the global Sentry object.

Benefits:

• Single download: one small script to fetch in parallel, reducing latency and round-trips.
• Slim footprint: the bundle should include only the core SDK plus the two micro-frontend features, keeping its gzipped size as small as possible so as not to impact page performance.
• Simplified integration: customers can add a single <script src="…/sentry.microfrontends.min.js"> and call Sentry.init({ ..., integrations: [Sentry.moduleMetadataIntegration()], transport: Sentry.makeMultiplexedTransport(...) }) without worrying about additional URLs.
• Cache efficiency: one bundle means better long-term caching and fewer cache invalidations.
• Lower maintenance: teams relying purely on CDN loads (no npm) avoid manual sync of multiple file versions.
• The multiplexed transport and module metadata features could be lazy-loaded, so that they are available in the Sentry Object only once an error occurs.

Product Area

Performance

[linear]

ENG-4757 Combined CDN bundle including core SDK, multiplexed transport and module-metadata integration

[getsantry]

Assigning to @getsentry/support for routing ⏲️

[linear]

JS-822 Combined CDN bundle including core SDK, multiplexed transport and module-metadata integration

[Lms24]

Hey @Laura-Arcidiacono thanks for writing in!

that forces us to load two additional files

You're correct, this is how we currently intend the SDK CDN bundle to be used with additional ("pluggable") integrations and APIs. We have so many permutations of bundles that we can't just reasonable build every combination.

That being said, you're making a good case for your usecase and I'm currently thinking, we could ship a bundle.mfe.min.js that includes the SDK (errors-only) with the two additional bundles as suggested. Before we pull the trigger on this, I want to bring it back to the team though, so no guarantees yet.

Would you be willing to submit a PR to build that bundle? Most of the building blocks should be in place and we can orient ourselves on the current bundle index files. Just let me know (no worries if not, we'll get to it).