SPIDR

Five Techniques to Split a User Story

Spike

Spikes are small, prototypical implementations of a functionality that is typically used for the evaluation and feasibility of new technologies.

Paths

If there are several possible alternative paths in a user story, one option is to create separate user stories from some of these paths. It is not absolutely necessary to write a story for each individual path, just where it makes sense.

Interface

Interfaces in this context can for example be different devices or device types, such as smartphones powered by iOS or Android. User stories can also be split in terms of this diversity.

Data

Another technique for splitting user stories can be used when the initial stories refer only to a sub-range of the relevant data.

Rules

Business rules or technological standards can be another splitting factor. Sometimes it makes sense to neglect technical specifications or business rules, if by doing so you can more quickly achieve a presentable result that satisfies the user or client.

source: https://blogs.itemis.com/en/spidr-five-simple-techniques-for-a-perfectly-split-user-story