Responder UUIDs

Identifying individual responders using a unique ID.
The responder UUID (Universally Unique Identifier) identifies a particular browser, using a value stored in the browser's localStorage.
Assigning a UUID allows repeat visits from the same responder to continue where they left off, and provides a useful way to tie together events, answers, and data for the same user.

Setting the responder UUID manually

You do not need to provide a responder UUID - Formsort will generate one on the responder's first session.
To provide your own UUID to use as an identifier, set responderUuid as a URL parameter when linking to a flow: ?responderUuid=123e4567-e89b-12d3-a456-426614174000
Or, you may provide it within the POST body: <input name="responderUuid" value="123e4567-e89b-12d3-a456-426614174000" />
It is not necessary to have an answer named responderUuid for this to work.
Setting responderUuid yourself is particularly useful if you already have an identifier generated for a particular user, like an account UUID or session UUID from your own application. Additionally, any responderUUID generated for a user can be passed along with that user either when being redirected to a new flow, out of a flow, or when returning to the same flow from a different device.
The responderUuid must, indeed, be a UUID - a 36 character hexadecimal string hyphenated with the pattern8-4-4-4-12, for example 123e4567-e89b-12d3-a456-426614174000.