What the extension does
The Hosted Data Layer extension lets iQ enrich or override page-provided data layer values with values Tealium hosts itself, keyed off a URL pattern or another identifier present on the page. Instead of trusting whatever the page happens to output, iQ looks up the correct value from a table you control.
When it is the right call
- A legacy or CMS-constrained site where engineering cannot ship a clean data layer on a timeline that matters
- A small number of pages needing a targeted correction rather than a platform-wide fix
- Content taxonomy that a CMS doesn't natively expose, but that a maintained lookup table can supply reliably
How to implement it properly
Define the lookup key precisely - usually the URL path, or another stable identifier present on the page - and confirm it is actually stable before building the table around it. Populate the hosted values deliberately and scope the extension only to the pages it should affect; an unscoped hosted layer that silently overrides pages it was never meant to touch is a debugging nightmare later. Treat this as a bridge: the moment the underlying CMS can ship the values natively, retire the hosted lookup rather than maintaining two systems indefinitely.
How to verify it worked
Using trace or preview tooling, confirm the hosted value appears in the resolved data layer for a URL inside scope - and just as importantly, confirm it does not appear (the page's own value passes through unmodified) for a URL outside scope. Both directions need to be tested; only checking the in-scope case misses the more common bug.
Say the quiet part out loud in the deliverable: a data layer that depends on a hosted lookup table to be correct is technical debt with a maintenance clock attached. It belongs in the handoff as a flagged item, not a quietly permanent fix.