WhatsApp

WhatsApp automation: every use case, and every limit

What an AI agent can and can't do on WhatsApp through the Business API, a WhatsApp Web gateway and your own phone. 24-hour windows, templates, ban risk, buttons, media, groups and bulk sending, compared honestly.

Every WhatsApp automation pitch shows the happy path. This post is the other half: which of the three ways to connect WhatsApp fits which job, and exactly where each one stops. We show the same limits on the New bot screen, so nobody finds out after launch.

ways to connect: Business API, WhatsApp Web, your phone

3

free-reply window on the Business API

24 h

ready bots, each checked against these limits

21

The three routes in one paragraph each

• WhatsApp Business Cloud API. Meta's official API on a dedicated number. Buttons, list menus, approved templates, delivery receipts, and no risk of a ban for using it as designed. The price is paperwork: business verification, a number that isn't on the WhatsApp app, and template approval for anything outside the 24-hour window.
• WhatsApp Web gateway. Your normal WhatsApp or WhatsApp Business app number, linked like WhatsApp Web to a small gateway on your machine. It can message anyone who has your number saved or has talked to you, read groups, and start conversations. It is unofficial, so it carries a real ban risk if it is abused.
• Your Android phone. Pocket reads WhatsApp notifications and replies through them, and taps Send for photos and files. Nothing to host, nothing to verify. It only works while the phone is on, and it can only answer chats that raise a notification.

Use cases, and which route fits

• Lead capture and qualification (admissions, clinics, coaching, car dealers): Business API for ads and click-to-chat at volume; WhatsApp Web for a small team working from an existing number.
• Appointments and bookings (salons, clinics, tutors, service visits): any route. Reminders a day later need the Business API with an approved template, or WhatsApp Web.
• Order status, payments and receipts (shops, restaurants, D2C): Business API. Link buttons for checkout and template receipts are only there.
• Support desks with photos and documents (AC repair, insurance claims, home repairs): Business API or WhatsApp Web. Both receive media reliably.
• Community and group updates (societies, alumni, classes, clubs): WhatsApp Web only. The Business API doesn't do normal groups, and the phone route only answers.
• A personal assistant on your own number (freelancers, founders, agents): the phone route, or WhatsApp Web if you have a machine running.
• Outbound campaigns to people who opted in: Business API with marketing templates. Not WhatsApp Web, and not the phone.

Limits of the Business API

• The 24-hour window. You can reply freely for 24 hours after the customer's last message. After that, only pre-approved templates, which are billed per message by category (marketing, utility, authentication).
• Templates need approval and can be paused if customers block or report them. Marketing templates are the strictest.
• Messaging tiers. A new number can start conversations with a limited number of people per day. The limit rises as your quality rating stays high.
• Interactive limits. Up to 3 reply buttons, up to 10 rows in a list, short button titles. Anything longer becomes text.
• Media size caps. Around 5 MB for images, 16 MB for video and audio, 100 MB for documents. Bigger files go as links.
• No ordinary groups, no calls, and one number per phone-number ID. The number can't also be used in the WhatsApp app.

Limits of the WhatsApp Web gateway

• No buttons or list menus. The bot sends them as numbered choices (“Reply 1, 2 or 3”), and the customer answers with a number.
• No templates, and no 24-hour window. That flexibility is exactly why it needs restraint.
• The machine must stay on. The gateway runs in Docker on your server or computer. The linked phone must come online at least every 14 days or WhatsApp unlinks it.
• One number per gateway, and WhatsApp Web changes can break it until the library updates. Pocket re-pulls the gateway on restart.
• Pace. Pocket spaces outbound messages, but hundreds of new chats an hour looks like spam to WhatsApp whatever the tool.

Limits of the phone route

• Android only, with notification access and the Pocket accessibility service switched on. iPhone doesn't allow either.
• Only chats that notify. Muted chats, archived chats and chats you have open on screen don't raise notifications, so the bot never sees them.
• Media needs the phone awake. Text replies go through the notification. Sending a photo or PDF opens WhatsApp and taps Send, so the phone must be unlocked, and it takes a few seconds per message.
• Inbound media needs WhatsApp's auto-download turned on for photos, videos and documents. Otherwise the bot only sees “📷 Photo”.
• It answers, it doesn't broadcast. It can open a chat with one number and send, but it isn't for lists or campaigns.
• Battery savers can kill it. Exclude Pocket from battery optimisation or replies stop when the screen has been off a while.

Limits that apply to every route

• The agent can be wrong. Keep prices, policies and availability in the brief or in your systems, not in the model's head. Every playbook tells the bot to check with a tool and hand over when unsure.
• Voice notes and calls. Voice notes arrive as audio the agent can listen to. WhatsApp voice and video calls can't be answered by any of the three routes.
• Every message costs tokens. A normal reply costs a fraction of a cent on a mid-tier model. Long threads with many photos cost more. The LLM cost calculator shows the monthly figure for your volume.
• Consent. Only message people who gave you their number for this purpose, and honour “stop” straight away. The bots do, on every route.

Choosing, in one line

Customers at volume, payments or campaigns: Business API. Your existing number, groups, or outbound to people you know: WhatsApp Web. A personal assistant with zero setup: your phone. You can run all three at once, and each conversation stays on the route it came in on.