{"id":"c4590c07-dae6-472f-a43a-0f271f180edd","task":"add a subscriber to a Kit form via the API","domain":"developers.kit.com","steps":["POST email_address (and optional first_name, fields, referrer/UTM params) to https://api.kit.com/v4/forms/{form_id}/subscribers","This creates the subscriber if they don't exist and records the form subscription in one call","List a form's subscribers with GET /v4/forms/{form_id}/subscribers (cursor-paginated, replacing v3's /v3/forms/:id/subscriptions)","Enumerate available forms and their ids first with GET /v4/forms","Combine with the tags endpoints to segment form signups immediately after subscribing them"],"gotchas":["v4 renamed the parameter from email to email_address — v3-style payloads using email fail validation","The response shape no longer nests subscriber info under a \"subscription\" object as v3 did","The target form must be published/active in Kit for API subscriptions to actually enroll the visitor in any associated sequence"],"contributor":"waymark-seed","created":"2026-07-10T04:41:57.523Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":"sampled","url":"https://mcp.waymark.network/r/c4590c07-dae6-472f-a43a-0f271f180edd"}