> ## Documentation Index > Fetch the complete documentation index at: https://cntillion.com/docs/llms.txt > Use this file to discover all available pages before exploring further. # WhatsApp AI agent for customer support > Connect a WhatsApp Business number through Meta so your agent answers customers, within the 24-hour window and with templates. Set it up and test it. Import a WhatsApp business account into your workspace, then choose the agent that answers its messages. If your team already uses the WhatsApp Business app on the number, you can usually keep using it alongside. ![WhatsApp card on an agent's Channels page with Add account and Manage workspace accounts](https://mintcdn.com/centillion/tB37dAnuJvIjXAdz/images/channels/whatsapp-01-channel-card.webp?fit=max\&auto=format\&n=tB37dAnuJvIjXAdz\&q=85\&s=660ec641204f766d405f1392a8805059) The agent's WhatsApp card lets you add an account imported into your workspace. ## What it does * Reads text, images, voice notes, audio and documents, and replies in up to 4,000 characters. * Replies freely inside WhatsApp's 24-hour window; after it, your team sends an approved template. * Works beside the WhatsApp Business app: a reply sent from the app pauses the agent on that conversation. * Saves the people who message you as leads, if you turn that on. * Pauses when the customer asks for a person, who takes over from the [helpdesk inbox](https://cntillion.com/docs/helpdesk.md). ## What you need * Admin rights on the Centillion workspace, and access to your Meta business. * A plan with integrations: Hobby and up. * A phone number you can verify. An existing WhatsApp Business app number is often eligible to stay in the app. * A display name for the number that follows Meta's display name guidelines. Meta reviews the name once the number reaches a higher messaging limit, but a 555 number that Meta gives you cannot send messages until its name is approved. * Two-step verification turned off, if the number has it on and you connect it without the Business app. Centillion registers the number with a new PIN, and Meta refuses that while another PIN is set. In WhatsApp Manager, open the number's **Settings**, then **Two-step verification**. New to Centillion? Start with [What Centillion is](https://cntillion.com/docs/introduction.md) and [Connecting a channel](https://cntillion.com/docs/channels/overview.md). This page covers what is specific to WhatsApp. ## Set it up **1. Import an account into the workspace** Open **More → Channels** in the workspace sidebar, choose **WhatsApp**, then **Import account**. If your team uses the WhatsApp Business app on this number, leave **Keep using the WhatsApp Business app** on. ![Workspace WhatsApp page before any accounts are imported, with an Import account button and Channels grouped under More in the sidebar](https://mintcdn.com/centillion/WLpDA0mJ1ryQ1IZ5/images/channels/whatsapp-02-workspace-accounts.webp?fit=max\&auto=format\&n=WLpDA0mJ1ryQ1IZ5\&q=85\&s=f56e02d3c1dc6d19d9c9c4167fe49ca5) Import WhatsApp accounts into the workspace before assigning them to agents. **2. Finish Meta's sign-up** Meta's own sign-up opens. Sign in, choose your business, and select or verify the number. Keep the Business app open on the phone if Meta asks you to link an existing number. The sign-up window expires after five minutes; if you lose your place, start again. **3. Check the number and assign an agent** Back in the workspace's WhatsApp page, check that the number shown is the one you meant. Centillion checks with Meta that the number belongs to the business you authorised. The imported account stays unassigned until you choose an agent. Open your agent's **Channels** page and choose **Add account** on the WhatsApp card. Select the imported account. Accounts assigned to another agent are shown there too, so you can see which agent is using them. You can also choose **Assign agent** from the workspace account list. Replies start paused after assignment. **4. Turn on replies and test** Turn on **Automatic replies**. Then message the number from another WhatsApp account and watch **Recent activity**. You can also choose WhatsApp in the Playground's channel menu: **Test on WhatsApp** shows a QR code and a link that open a chat with the connected number on your phone. When the number cannot be read from the connection, the card only says so. If the account is already imported, skip Meta's sign-up and add it from the agent's WhatsApp card. **Manage workspace accounts** opens the workspace list. To move an account to another agent, choose **Remove agent** in that list, then assign it again. The account stays imported, automatic replies pause, and existing conversations stay with the previous agent. If Meta finishes an account migration, or grants API access without a number, Centillion stops and says so: neither leaves a number it can connect yet. If Meta refuses to register the number, the dialog says why and you can try again without closing it. ## Use it every day ### The 24-hour window WhatsApp only lets a business send a free-form message within 24 hours of the customer's last message. This is Meta's rule, and it applies to your team as much as to the agent. Inside the window, the agent replies normally. Outside it, WhatsApp refuses the message, so Centillion does not try; the conversation waits in Helpdesk instead. ### Templates, for outside the window To reach someone after 24 hours you send an approved template. Open the ticket in Helpdesk, pick a template, fill in its variables from the customer's details or with your own text, preview it, and send. Templates have to be created and approved in WhatsApp Manager first, and only approved ones with a text body appear in the picker. Meta charges your WhatsApp Business account for template messages, by category, and bills you directly. To send a template to many customers at once, with a playbook the agent follows when they reply, use an [outbound campaign](https://cntillion.com/docs/campaigns.md). ### Answering from Slack When the agent hands a WhatsApp conversation to your team, they can also answer it from a Slack thread, as long as the Slack workspace is connected to the same agent as the number. The 24-hour window applies there too: once it has closed, the thread says the reply was not sent, and the template has to go out from the ticket. A file added to a reply in the thread goes with it, within WhatsApp's limits: JPEG and PNG images up to 5 MB, MP4 videos and audio up to 16 MB, and documents. ### Working alongside the Business app If your team replies from the WhatsApp Business app, Centillion imports that reply and pauses the agent on that conversation, so two answers never go out at once. During setup, history and contact names are imported so your team has context. Imported history is never replied to. ### Collecting leads In the Playground's WhatsApp **Leads** tab, turn on **Enable automatic collection of leads** and pick the numbers it applies to. When someone messages one of them, their phone number and the profile name WhatsApp shares are saved as a lead. Later messages from the same person update that lead instead of adding another. Imported history and your own replies never create leads. ### Opt-outs and handoff A customer who replies `STOP` stops receiving automatic replies, and their number goes on your workspace's do-not-call list. `START` turns the replies back on; it does not take the number off the do-not-call list. Common equivalents work too, in several languages, including `unsubscribe`, `cancel` and `parar`. Asking for a person pauses the conversation for your team. When a customer sends both in quick succession, the one they sent last counts, going by the times WhatsApp puts on the messages. If both were sent in the same second, the opt-out stands. A confirmation still waiting to go out is dropped when a newer command contradicts it. One already sent cannot be taken back, so a customer can receive both. ## Limits and good to know * **What the agent reads.** Text, images, voice notes, audio, and PDF, DOCX, TXT, Markdown, CSV and JSON documents. Images go to a model that can see them, voice notes are transcribed, and documents have their text pulled out. * **File sizes.** Images and documents under 5 MB; audio up to 20 MB. PDFs up to five pages and 2,000 tokens per page. Each image or PDF page adds the model's credit rate to the request. Anything bigger is marked for a person instead of being read, and so are video, stickers, locations and anything else the agent cannot interpret. * **Reactions.** Emoji reactions are ignored. A customer's reaction gets no reply and leaves nothing to review, and one your team adds from the Business app does not pause the agent. * **Registration attempts.** Meta allows 10 registration attempts per number in 72 hours. Once a number has used them, wait 72 hours before connecting it again. * **Meta's side.** Meta decides whether a number can keep using the Business app, by business, number, country and app. A personal WhatsApp account is not a WhatsApp Business app account and has different rules. Business verification and access approvals happen at Meta before a number can send at any volume. * **What Meta charges for replies.** From October 1, 2026, Meta charges per message for service messages: the free-form messages sent inside the 24-hour window, the agent's replies included. Each number gets 1,000 free service messages a month, and unused ones do not roll over. Above that, Meta delivers replies only if the account has a payment method: in WhatsApp Manager, open **Overview** and choose **Add payment method**. * **Disconnecting.** Disconnecting in Centillion removes the account from the workspace and deletes the stored credential. It leaves your Meta side untouched: the number stays registered and the business connection stays in place, because other numbers may share it. To remove the platform connection, do it from WhatsApp Business settings as well. ## Questions ### Can my team keep using the WhatsApp Business app on the same number? Often, yes. Turn on the option to keep using the app when you connect, and keep the app open on the phone during sign-up. Meta decides eligibility by business, number, country and app. ### Why did the agent not answer a customer who wrote yesterday? The 24-hour window had closed. WhatsApp refuses free-form messages after it, so the conversation waits in Helpdesk and your team sends an approved template from the ticket. ### Do I pay Meta for the agent's replies? From October 1, 2026, above 1,000 free service messages per number each month. Meta bills your WhatsApp Business account directly. ### Meta refused to register my number. What now? The dialog shows Meta's reason, and you can try again without closing it. If the number has two-step verification on and you are not using the Business app, turn it off in WhatsApp Manager first. After 10 attempts in 72 hours, wait 72 hours. ### Can the agent read voice notes and PDFs? Yes. Voice notes are transcribed and document text is read, within the size limits above. Video, stickers and locations go to a person. ## Try it Connect a number, turn on automatic replies, and send it a message from your own phone. The reply and the conversation show up in the dashboard. > [card] [Start free](https://app.cntillion.com/sign-up?utm_source=docs\&utm_medium=article\&utm_campaign=channels-whatsapp) > > Start on the Free plan, or take a seven-day trial of a paid plan. Your agent is live on your site in an afternoon. > [card] [Book a demo](https://cal.com/patrick-turricelli-smgfks/15min?utm_source=docs\&utm_medium=article\&utm_campaign=channels-whatsapp) > > Fifteen minutes with the team, on your own use case. Or ask the assistant on this page. ## Related > [card] [What Centillion is](https://cntillion.com/docs/introduction.md) > > The product in one page: agents, knowledge, channels and the helpdesk. > [card] [Helpdesk](https://cntillion.com/docs/helpdesk.md) > > Where your team answers WhatsApp conversations and sends templates. > [card] [Outbound campaigns](https://cntillion.com/docs/campaigns.md) > > Send an approved template to many customers, with a playbook for replies. This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.