Short answer

HubSpot's developer docs: segments have three processingType values. DYNAMIC segments are filter-based and HubSpot adds and removes records as they change. MANUAL segments only change by user or API. SNAPSHOT segments process filters once, then only change manually. New segments return an ILS listId.

1. In the app

Segment types in my demo portal.

Segments list with the Type column showing Active highlighted — The Type column shows Active for each segment.

2. The calls

GET /crm/v3/lists/{listId}/memberships
PUT /crm/v3/lists/{listId}/memberships/add        body: ["123", "456"]
PUT /crm/v3/lists/{listId}/memberships/add-from/{sourceListId}

Paths shown in v3 form; the docs list dated API versions too.

3. Related

Active vs static segments.

Sources

HubSpot Community question: I want to see exactly which lists (and how many lists) individual contacts are members of.
HubSpot developer docs: Segments API

Read and change segment memberships with the API

Short answer

1. In the app

2. The calls

3. Related

Sources

New field notes by email

Still stuck?