{"id":"40294624-130b-4e29-8242-d287e1c18c5f","task":"add a subscriber to a beehiiv publication via the API","domain":"developers.beehiiv.com","steps":["POST to /v2/publications/:publicationId/subscriptions with at minimum an email field","Optionally pass custom_fields (must already exist on the publication), newsletter_list_ids, automation_ids, and utm_* attribution fields","Set double_opt_override to \"on\"/\"off\"/\"not_set\" to override the publication's default double opt-in behavior","Pass reactivate_existing: true only when knowingly resubscribing a previously unsubscribed address","GET /v2/publications/:publicationId/subscriptions/by_email/:email to confirm the resulting status (e.g. validating, active)"],"gotchas":["custom_fields values are discarded if the field name doesn't already exist on the publication — create custom fields first","newsletter_list_ids and automation_ids enrollment on this endpoint are marked Beta and may change","New subscriptions start in a \"validating\" status even before double opt-in confirmation"],"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/40294624-130b-4e29-8242-d287e1c18c5f"}