1. [Help](https://nuvia.ai/en/docs) 2. [Channels](https://nuvia.ai/en/docs/colecoes/19378288-channels) 3. [WhatsApp](https://nuvia.ai/en/docs/colecoes/19430943-whatsapp) # Understanding WhatsApp rules: 24h and 72h windows and templates You have 24 hours for free-form messages after the lead contacts you; outside that, you must use HSM templates approved by Meta. Updated on August 3, 2026 [WhatsApp](https://nuvia.ai/en/docs/colecoes/19430943-whatsapp) 1. [Understanding WhatsApp rules: 24h and 72h windows and templates](https://nuvia.ai/en/docs/artigos/14575042-understanding-whatsapp-rules-24h-72h-windows-templates) 2. [How to sync Nuvia conversion data with Meta (CAPI)](https://nuvia.ai/en/docs/artigos/15421878-how-to-sync-nuvia-conversion-data-with-meta-capi) 3. [How to migrate a WhatsApp number from another platform to Nuvia](https://nuvia.ai/en/docs/artigos/16414388-migrate-whatsapp-number-from-another-platform-to-nuvia) 4. [How to improve the response rate of WhatsApp campaigns](https://nuvia.ai/en/docs/artigos/14501604-how-to-improve-response-rate-whatsapp-campaigns) 5. [WhatsApp Business Coexistence with Nuvia](https://nuvia.ai/en/docs/artigos/15554165-whatsapp-business-coexistence-with-nuvia) 6. [How to create a Meta Business account](https://nuvia.ai/en/docs/artigos/16548186-how-to-create-meta-business-account) ## What is the messaging window? The **messaging window** is the period during which you can send messages without format restrictions. ### 24-hour window (default) Whenever a contact **sends you a message**, you have **24 hours** to reply with free-form messages (no HSM template needed). This count restarts with each message received. **Example:** - Monday, 10:00 **→** contact sends a message - Monday, 10:01 to Tuesday, 10:00 **→** you can send free-form messages - Tuesday, 10:01 onward **→** you need to use an HSM template #### 72-hour window (Click to WhatsApp) If you use **Click to WhatsApp ads** (ads that lead to WhatsApp), Meta offers an extended **72-hour** window to send free-form messages. This only works with the **WhatsApp Cloud API**. **Requirements to enable 72h:** - Connect the account via the **WhatsApp Cloud API** (not via WhatsApp Business/Evolution) - Have ad campaigns set up in Meta Ads Manager How Nuvia detects the 72-hour window The 72-hour CTWA window is activated **only on the first message** from the contact that arrives with Meta's referral signal (identifying that the lead clicked a Click-to-WhatsApp ad). Later messages from the same contact (which arrive without referral) open a standard 24-hour window. This makes sure the platform respects the actual window defined by Meta and avoids send errors outside the allowed period. ### What is an HSM (Highly Structured Message)? An **HSM template** is a message pre-approved by Meta that you can use **outside the 24h/72h window** to reach cold leads or re-engage contacts who didn't reply. #### HSM template characteristics AspectDetail **Approval** Submitted for Meta approval; takes minutes to hours **Components** Header (text, image, video, document), body, footer, buttons **Variables** Use var_ for personalization (e.g., var_business_name = company name) **Legal requirement** Must clearly indicate opt-in or prior context of consent **Limit per number** Maximum of 6,000 templates per WhatsApp number **Reuse** An approved template can be reused without limit Rejected templates block the campaigns that depend on them. Review the template and resubmit it. #### When do you need an HSM? SituationRequired?Why? Replying to a message received within 24h (or 72h) No You're inside the window Sending a first-contact campaign (cold outbound) Yes You're outside the window Following up with contacts who didn't reply within the window Yes The window has expired Smart Follow-up after a closed conversation Yes Re-engagement requires a template AI agent starting a conversation Yes Always outside the window ### Smart Follow-up and the window rules Nuvia's **Smart Follow-up** feature automatically respects WhatsApp's rules: - **Inside the 24-hour (or 72-hour) window:** sends a free-form message, no template - **Outside the window:** automatically switches to an HSM template - **No template available:** the Follow-up isn't sent; you see a warning Set up the templates you'll use in Follow-ups in advance. Don't leave approval to the last minute. ### Daily sending limits (Tiers) WhatsApp limits how many messages you can send per day, depending on your account: TierDaily limitTypical use case Tier 1 1.000 New accounts, initial tests Tier 2 10.000 Small SDR teams Tier 3 100.000 Mid-sized operations Tier 4 No limit Companies at scale (100K+ contacts/day) You start at Tier 1. To scale up, show consistent quality (low block rate) for 7 days. ### WhatsApp rules that affect your campaigns #### Don't send cold promotional messages without a template If you don't have an open window (the contact hasn't replied in more than 24h/72h), any message must go through an HSM. Sending it any other way violates WhatsApp's policies, and your account may be restricted. #### HSM templates must be clear and respectful Meta rejects templates that: - Look like spam (e.g., “Grab it NOW! UNMISSABLE DISCOUNT!!!”) - Ask for sensitive data (e.g., passwords, credit card) - Include suspicious links or unknown URL shorteners - Suggest implied consent (“you will be added to…”) #### Avoid account blocks - Don't use the same message for hundreds of contacts without variation - Don't send test messages to real numbers (use WhatsApp test numbers) - Respect your Tier limit; don't exceed your daily quota - Monitor the block rate; above 5%, investigate your templates ## Frequently asked questions ## Frequently asked questions **Can I send free-form messages without an HSM to an old contact who replied a month ago?** No. The 24-hour window is continuous and only restarts when the contact sends a new message. After 24h, any message from you needs an HSM. **Does the 72-hour window work automatically?** No, you need to be connected via the WhatsApp Cloud API. WhatsApp Business doesn't offer 72h. Check which connection you use in **Side menu > Platform > Channels**. **I received several messages from the same contact coming from a Click-to-WhatsApp ad. Does the 72-hour window still apply to the following messages?** The 72-hour window only applies to the first message that arrives with Meta's referral signal. Later messages from the same contact (which arrive without referral) open the standard 24-hour window. If you need to reply after the first 24 hours, use an HSM template, unless the contact sends a new message and reopens the window. **The 72-hour window used to stay open for the whole CTWA conversation. What changed?** The platform was adjusted to respect the actual window defined by Meta. Keeping the 72-hour window on later messages (which don't carry referral) caused send errors (Meta error 131047), because Meta had already closed the extended window. Now only the first message with referral gets 72h; the rest follow the standard 24h. **My template was rejected. When can I resubmit it?** Right away. Adjust the template in Nuvia and resubmit it. Meta will take minutes to hours to review it again. **How many active templates can I have per number?** Up to 6,000. In practice, you need far fewer (50–200 templates is normal). Archive unused templates to stay organized. [NextHow to sync Nuvia conversion data with Meta (CAPI)](https://nuvia.ai/en/docs/artigos/15421878-how-to-sync-nuvia-conversion-data-with-meta-capi) Was this article helpful? ## Related articles - [How to improve the response rate of WhatsApp campaigns](https://nuvia.ai/en/docs/artigos/14501604-how-to-improve-response-rate-whatsapp-campaigns) - [How to set up and use Smart Follow-ups in Nuvia](https://nuvia.ai/en/docs/artigos/14580483-how-to-set-up-use-smart-follow-ups-nuvia) - [Understanding LinkedIn rules and limits for campaigns](https://nuvia.ai/en/docs/artigos/14590400-understanding-linkedin-rules-limits-for-campaigns) - [How to use variables in WhatsApp templates in Nuvia](https://nuvia.ai/en/docs/artigos/15353096-how-to-use-variables-in-whatsapp-templates) - [How to send Nuvia WhatsApp templates straight from a HubSpot workflow](https://nuvia.ai/en/docs/artigos/15879535-send-nuvia-whatsapp-templates-from-hubspot-workflow) [WhatsApp](https://nuvia.ai/en/docs/colecoes/19430943-whatsapp) 1. [Understanding WhatsApp rules: 24h and 72h windows and templates](https://nuvia.ai/en/docs/artigos/14575042-understanding-whatsapp-rules-24h-72h-windows-templates) 2. [How to sync Nuvia conversion data with Meta (CAPI)](https://nuvia.ai/en/docs/artigos/15421878-how-to-sync-nuvia-conversion-data-with-meta-capi) 3. [How to migrate a WhatsApp number from another platform to Nuvia](https://nuvia.ai/en/docs/artigos/16414388-migrate-whatsapp-number-from-another-platform-to-nuvia) 4. [How to improve the response rate of WhatsApp campaigns](https://nuvia.ai/en/docs/artigos/14501604-how-to-improve-response-rate-whatsapp-campaigns) 5. [WhatsApp Business Coexistence with Nuvia](https://nuvia.ai/en/docs/artigos/15554165-whatsapp-business-coexistence-with-nuvia) 6. [How to create a Meta Business account](https://nuvia.ai/en/docs/artigos/16548186-how-to-create-meta-business-account) ## Still need help? Customers reach support through the chat inside the platform. Not a customer yet? Talk to our team. [Talk to support in the platform](https://app.nuvia.ai) [I'm not a customer yet](https://nuvia.ai/en/contact) --- Source: https://nuvia.ai/en/docs/artigos/14575042-understanding-whatsapp-rules-24h-72h-windows-templates