WhatsApp Business API documentation

WhatsApp Business API is Meta's official interface for medium and large businesses to communicate with customers at scale. Unlike the regular WhatsApp Business app, the API allows integration with CRM systems, automated messaging, chatbots, and supports unlimited agents on a single number.

Meta charges per template message delivered, priced by the recipient's country and the template's category. Meta publishes a rate card per billing currency, and an account is billed on the card for its own currency. On Meta's US dollar card effective July 1, 2026, a number in the United States or Canada is US$0.0250 for marketing and US$0.0034 for utility and authentication, and a Singapore number is US$0.0732 and US$0.0160. From October 1, 2026 Meta also charges for service messages, the replies you send inside a customer's 24-hour window. Each business number gets 1,000 free service messages a month, and Meta charges the market's utility rate beyond that. Rates differ by country and by message category.

Error 131026 occurs when you try to send a message outside the 24-hour customer service window without using an approved message template. To fix it, either use a pre-approved template message or wait for the customer to message you first to reopen the 24-hour window.

WhatsApp Business API messaging limits are set per business portfolio and count unique customers you message outside the 24-hour window in a rolling 24 hours. The tiers are 250, 2,000, 10,000, 100,000 and Unlimited. A new portfolio starts at 250 and reaches 2,000 through business verification or enough high-quality sends, then moves up a tier when it uses at least half its limit in seven days with a good quality rating.

Message templates are created in Meta Business Manager under WhatsApp Manager > Message Templates. Templates must be approved by Meta before use, and Meta's template documentation says review can take up to 24 hours. They can include text, headers, buttons, and variables for personalization.

The 24-hour rule means you can only send free-form messages within 24 hours of a customer's last message. After 24 hours, you must use pre-approved message templates which require Meta approval. This protects users from spam and is strictly enforced.