Schedules a WhatsApp message (text, or a file with optional caption) to one person or group for a later time, once or repeating (e.g. "every Monday at 9:00"). Paid plan only: on the free plan the call is refused with a note on how to subscribe. to works like send_message's and is resolved now, so a wrong name fails right away. Time: pass send_at as an ISO 8601 date-time with the user's UTC offset for that date (e.g. "2026-10-10T09:00:00-06:00"), and timezone as the user's IANA timezone (e.g. "America/Mexico_City"). Use the timezone and current time you know for the user; if you don't know them, ask. Mind daylight saving time: the offset must be the one in effect on that date. The first send must be in the future and at most a year ahead. Messages go out within about a minute of send_at; if the server is down for more than an hour past send_at, that send is marked missed instead of being sent late. Repeats: recurrence once (default), daily, weekly, biweekly, monthly, quarterly, semesterly or yearly, always at the same local time (a monthly message on the 31st goes on the last day of shorter months); optional until (a date like "2026-12-31", or a date-time with offset) ends the series. Each send is tried once: a failure is recorded (see list_scheduled_messages) and the series continues. Quoted replies aren't supported. Files: media.url or media.message_id (checked now and fetched again at send time; message_id only for one-off messages, so prefer a link); media.data isn't accepted. The result gives the local time and how long until it (when) and, for repeats, the first sends: read them back to the user. To change a scheduled message, cancel it with cancel_scheduled_message and schedule it again. At most 100 upcoming scheduled messages per account. If you are writing the text yourself rather than sending words the user gave you, call get_writing_style for this chat first and write it the way the user writes; skip that for dictated text. WhatsApp doesn't render Markdown: use bold, italic, strikethrough and "- " lists, and never send tables, # headings, double asterisks or text links. Write a table as short lines (e.g. "Ana: $200") and paste URLs plain. Only format when it suits the message. To tag (mention) someone in a group so they get notified, write @ followed by their full phone number with country code, digits only (e.g. "@5215512345678", not "@Ana" or "@+52 55…"); WhatsApp shows their name in its place. Get the number from phone_display (read_chat_history participants or search_contacts). Never use the digits of a lid_jid. Messages that start new conversations have extra protection against WhatsApp's anti-spam bans and may be delayed or refused; the result says so and when. Sending the same text, especially with a link, to many people who haven't written to the user can get their number temporarily or permanently banned, even when spaced out: write each person their own message (not just a name swap), and warn the user about this risk when they ask for outreach. Confirm the recipient, text, file and time with the user first unless they already gave them. Returns the scheduled message { id, series_id (shared by every send of a repeating message), kind? ("queued" for a send_message that was queued to go out automatically; absent for scheduled messages), status (scheduled, processing, sent, failed, missed or cancelled), recipient (contact fields (name; name_source: address_book, push_name, group_subject, business, phone or unresolved; canonical_jid: the JID to pass to send_message and read_chat_history; phone_jid and lid_jid: the chat's phone-number and LID forms, null when unknown or for groups; phone_display: the number as +).), text?, media?, send_at (UTC), send_at_local, when (readable local time and how far away), timezone, recurrence, occurrence? (0 = first send of a series), until?, sent_at?, message_id? (once sent), error? (why it failed or was missed) } plus next_occurrences for repeats.