> ## Documentation Index > Fetch the complete documentation index at: https://docs.polymorfa.com/llms.txt > Use this file to discover all available pages before exploring further. # Send a follow-up after delivery or read > Send one follow-up message from the same number, timed from when the first message was delivered or read. Replies and opt-outs cancel it. A campaign can send each recipient one follow-up message. The wait starts when WhatsApp reports the first message as delivered or read, and the follow-up comes from the number that sent the first message. A recipient who replies or opts out never gets it. Follow-ups are a beta. When the beta is offered to your team, a team owner or admin selects **Join** on the Receipt-timed campaign follow-ups beta row in the campaign builder's message step, reviews the terms and selects **Accept and join**. Until your team has joined and the beta is available to it, requests that set a follow-up, or launch or copy a campaign that has one, answer `403 feature_unavailable`. Removing a follow-up from a draft always works. ## How the timing works * **Delivery starts the wait.** The follow-up is due its delay after WhatsApp first reports the first message as delivered. * **A read takes precedence.** If WhatsApp reports the first message as read before the follow-up starts sending, the wait restarts from that first read. Later reads do not move it again. * **No receipt, no follow-up.** A follow-up never sends on a timer alone. Recipients who turned off read receipts report deliveries only, so their wait starts from delivery. * **Expiry never sends.** The expiry counts from when the first message was sent. A follow-up that is not sent by then is marked `expired` and never sent. | Setting | Default | Allowed range | | - | - | - | | `delaySeconds` | 86,400 (1 day) | 60 to 604,800 (7 days) | | `expirySeconds` | 604,800 (7 days) | 86,400 to 2,592,000 (30 days), and longer than the delay | The campaign's [send window](/guides/campaigns/send-a-campaign) also applies: a follow-up that falls due outside the window waits for the next opening, as long as it has not expired. ## What cancels a follow-up * The recipient replies to the number that sent the first message. * The phone number is added to your opt-out list, whether by a STOP keyword, the API, an import or the console. A later START does not restore a cancelled follow-up. * You stop the campaign. * The sending number changes: it is renamed, connected again as a new connection, or switches sending type. A follow-up is only ever sent from the original number and connection. * Your team leaves the beta, or the beta is turned off. Pausing a campaign holds follow-ups. Their waits keep counting, so a follow-up whose expiry passes while the campaign is paused expires without sending. While the sending number is offline or disabled, the follow-up waits until it returns or the follow-up expires. A follow-up that has started sending is never recalled or sent twice. If its result is unknown, for example after a connection drop, Polymorfa reconciles it from the original send and reports `outcome_unknown` until it can prove the outcome. ## Requirements * The campaign sends one first message: a single composed message or a template. A campaign with a sequence of composed messages cannot launch with a follow-up. * The follow-up is either text (1 to 16,384 characters, with the same `{{variable}}` placeholders as the campaign) or a message template (`templateId`). Follow-up text cannot contain tracked links (`{{link:key}}`). * On a Cloud API number, the follow-up follows the same 24-hour window rule as any composed message: outside it, a text follow-up fails. Use an approved template to reach recipients outside that window. * The follow-up fills its variables the same way as the first message, including the campaign's variable mapping. A recipient without a value for a variable that has no inline fallback does not get the follow-up; it ends as `failed` with reason `missing_variable`. The console accepts only variables that the first message or its mapping already uses. * You can add, change or remove the follow-up only while the campaign is an unlaunched draft. Launch freezes it. * A/B tests and weighted variations work with follow-ups: each recipient's own first message starts their wait. Waiting, receipts and cancellations are free. Each follow-up that is sent is a campaign message, with the same funding, plan and safety checks as the first message. ## Add a follow-up ### Use the console In the campaign builder's message step, turn on **Send one follow-up**, write the message or choose a message template, and set how long to wait and when to stop waiting. The review step shows the follow-up before you launch. ### Use the API Send `followUp` when you create or update a draft: ```bash theme={null} curl -X PATCH "https://api.polymorfa.com/messaging/projects/$PROJECT_SLUG/campaigns/$CAMPAIGN_ID" \ -H "Authorization: Bearer $POLYMORFA_KEY" \ -H "Content-Type: application/json" \ -d '{ "followUp": { "delaySeconds": 86400, "expirySeconds": 604800, "message": { "type": "text", "text": "Hi {{first_name}}, still interested? Reply YES to hold your size." } } }' ``` To send a message template instead, use `"message": { "type": "template", "templateId": "