WhatsApp automation: what the Cloud API allows for messages, templates and replies
WhatsApp automation runs on one rule: when a customer messages you, a 24 hour customer service window opens, and inside it your automation can send any message type it likes. Once it closes, only a pre-approved template goes through. Everything else, the bots, the auto-replies, the broadcast tools, is built on top of that single constraint.
Get the window right and WhatsApp automation is simple. Get it wrong and your automation silently stops delivering, which is how most projects discover the rule.
The 24 hour window, and what it changes
Meta's send messages guide describes it precisely: when a user messages or calls you, "a 24-hour timer called a customer service window starts". If they contact you again before it expires, the window resets to a full 24 hours. The user must also have opted in to receive your messages.
| Window open | Window closed | |
|---|---|---|
| Free-form text | Yes | No |
| Image, audio, video, document, sticker | Yes | No |
| Contacts, location, reactions | Yes | No |
| Interactive lists and reply buttons | Yes | No |
| CTA URL button, voice call button, Flows | Yes | No |
| Commerce messages tied to a catalog | Yes | No |
| Pre-approved template | Yes | Yes, this is the only option |
So the design question for any WhatsApp automation is not "what can I send" but "is the window open right now". An automation that answers an inbound message in seconds has the full toolkit. An automation that reaches out first, a reminder, an abandoned cart, a re-engagement, has templates and nothing else.
What it costs, and why the window matters to your bill
Meta moved to per-message billing on July 1, 2025, replacing conversation-based pricing. Only template messages are billed, by category, volume tier and the recipient's country code. The categories are Marketing, Utility and Authentication, and Meta is explicit that "a business accepts the charges associated with the category applied to the template at time of use", so a template miscategorised as Marketing costs you Marketing rates.
Three things are free, read on Meta's pricing doc today:
- Non-template messages inside an open 24 hour customer service window.
- Utility templates sent inside an open customer service window.
- Everything for 72 hours when the user arrived through a Click to WhatsApp ad or a Facebook Page call-to-action on the Android or iOS app. Desktop and web are not supported for that free entry point.
Which turns the rule into an economic one: an automation that replies fast, inside the window, is free. An automation that broadcasts is a line item. The full rate structure, the four categories and the 2026 rate calendar are in WhatsApp Business API pricing.
The real limits on automating WhatsApp messages
Read on Meta's Cloud API overview today:
| Limit | Value |
|---|---|
| Messages per second, per business phone number | 80 by default, upgrades available |
| Messages to the same user | 1 every 6 seconds, roughly 600 an hour |
| Burst to the same user | Up to 45 in 6 seconds, which reduces your future quota |
| API requests per hour, per WABA | 200 by default, 5,000 once a phone number is registered |
| Retry after a failed send | 4^X seconds, X increasing per failure |
The 200 requests an hour default is the one that catches new integrations: it only lifts to 5,000 once the WABA has at least one registered phone number. Unverified WABAs also sit under a test message rate limit, and verified ones under a quality rating that moves with blocks and reports.
To use the Cloud API at all you need a business portfolio, a WhatsApp Business Account, and a business phone number. Verifying the portfolio is optional but it improves throughput and Official Business Account eligibility.
A WhatsApp bot or the Cloud API?
"WhatsApp bot" covers two very different things, and the difference decides whether your number survives.
The first kind drives WhatsApp Web or a reverse-engineered client with a script. It can do anything a human can: message anyone, scrape groups, send at any hour, no templates, no approvals. It is also outside Meta's terms, and the failure mode is the number being banned with the conversation history attached to it.
The second kind calls the Cloud API. It lives inside the 24 hour window, it uses approved templates outside it, it respects 80 messages a second, and it keeps working. Every tool worth paying for is in this family.
| Path | Price read today | What it adds | Who it is for |
|---|---|---|---|
| Cloud API direct from Meta | No platform fee, Meta template rates per message | Nothing, you build the inbox, the window logic and the retries | Teams with developers |
| Twilio | $0.005 per message in or out, plus Meta template fees, $0.001 per failed message | Delivery infrastructure, link tracking and scheduling as a $0.015 per message add-on with the first 1,000 free each month | High volume senders |
| Wati | Base price not published on the page, extra users at $24 per user per month (Pro), $69 (Business) | Agent inbox, chatbots, 2,000 free automation triggers a month on Pro | Support teams |
| PlugKit | $49 a month for 5 connected accounts, cancel anytime | WhatsApp messages and templates in the same API and MCP server as Instagram, LinkedIn, TikTok, YouTube, X, Facebook and Telegram | Developers and AI agents |
Prices read on each vendor's own page on October 19, 2026. Wati publishes its add-on prices but not its base plan prices, so I am not going to guess them.
Where PlugKit stops, and it matters
PlugKit connects WhatsApp for messages only. Its own docs call WhatsApp "a conversation channel" with "No posts, no comments, no analytics", and that is accurate: there is nothing to post on WhatsApp. What it does carry is two-way messaging on the customer's own number, with inbound messages arriving by webhook and readable from the unified inbox, plus approved templates listed per WhatsApp Business Account and sent with named language and numbered variables.
The window rule is enforced, not worked around: free-form text is accepted only within 24 hours of the contact's last message, and after that only an approved template. Campaigns follow the same rule. The endpoints are POST /v1/inbox/conversations to open or find a conversation for a phone number, POST /v1/inbox/conversations/{id}/messages to send text or a template, and GET /v1/accounts/{id}/message-templates to list what is approved. Connection goes through Embedded Signup at GET /v1/connect/whatsapp.
So if you want WhatsApp automation and Instagram automation behind one interface, that works. If you want WhatsApp broadcast campaign tooling with segmentation and A/B tests, a dedicated WhatsApp platform is the better buy, and I would say so to your face.
What to automate first
In order of payoff, from the Instagram equivalents that already work:
- The instant reply inside the window. Someone messages, your automation answers in seconds, free of charge, with the full message toolkit.
- Triage. Route by intent, hand the hard ones to a human. The 24 hour clock makes speed worth real money here.
- One or two utility templates. Order shipped, appointment tomorrow. Utility inside an open window is free, and these are the templates people do not report.
- Marketing broadcast, last. It is the expensive category, it carries the block and report risk that moves your quality rating, and it is the one that gets numbers restricted.
The comment-to-DM pattern that works so well on Instagram does not transfer, because WhatsApp has no comments. The closest equivalent is a Click to WhatsApp ad, which also buys you the 72 hour free entry point window. For the Instagram side of all this, read Instagram DM automation, and for what ManyChat charges to do it across channels, ManyChat pricing. The platform by platform index is at Instagram and social automation.
FAQ
Can you automate WhatsApp messages?
Yes, through the WhatsApp Cloud API. Inside the 24 hour customer service window that opens when a customer messages you, an automation can send any message type. Outside it, only pre-approved templates. Automating WhatsApp Web with a script is a different thing and risks the number being banned.
What is the 24 hour rule on WhatsApp?
When a user messages or calls your business, a 24 hour customer service window opens, and it resets to 24 hours each time they contact you again. Inside, free-form messages are allowed and free. Once it closes, only approved template messages are delivered.
Do I need a template to send a WhatsApp message?
Only to message someone outside an open window, or to start a conversation yourself. Templates come in Marketing, Utility and Authentication categories, are approved by Meta before use, and are billed per message by category and country. Inside an open window, free-form messages need no template.
How many WhatsApp messages can I send per second?
A business phone number sends up to 80 messages per second by default, with capacity upgrades available. To a single user the limit is one message every 6 seconds, about 600 an hour, with bursts of up to 45 in 6 seconds that reduce your later quota.
Is WhatsApp automation free?
The API has no platform fee from Meta, and non-template messages inside an open 24 hour window cost nothing. Templates are billed per message by category and country. Tools on top charge their own fee, from $0.005 per message at Twilio to a monthly subscription elsewhere.
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