22 August 2025

Designing fallback events

A fallback event is a signal you still collect when optional analytics is refused. It is not a clever hash of the same payload. If the payload would have been a behavioural dossier, hashing it does not make it a server log.

Useful remainders tend to be coarse: template family served, HTTP status, whether a named form endpoint returned 201, approximate country from the CDN if you already process that for delivery. Useless remainders include canvas fingerprints “for bots”, bouncing click IDs through the thank-you page, and stuffing localStorage because “it is first party”.

Write each fallback with a purpose sentence a lawyer can read. “Count how many checkout POSTs succeeded today” is a purpose. “Understand the customer journey” is a slogan. In studio critiques we strike slogans.

Volume will look small next to a fully cookied property. That is expected. Do not inflate with modelled rows. If leadership needs a richer picture, they can ask for a grant rate programme — clearer copy, fewer dark patterns we will not teach — rather than a louder pixel.

Module four of Consent Signal Architecture is a working session on this catalogue. Come with one event you suspect is a pretend fallback. We will say so in front of the group.