the AI agent that sells and supports on WhatsApp.
heysteff is an AI platform for customer support and sales across WhatsApp, Instagram, Messenger, Gmail and Shopify; Steff is the AI agent that runs it. On WhatsApp — the channel where most of your customer conversations already happen — that means replying in seconds, selling inside the chat, and booking appointments, whether or not you have a Meta-verified number.
Official Business Platform and unofficial number, side by side
heysteff supports two ways to connect WhatsApp, and you can use whichever fits you today: the WhatsApp Business Platform Cloud API, Meta's official API with a verified number (they help you get one, and it also accepts numbers provisioned through Twilio or 360dialog), or an unofficial number over Baileys for the number you already use, without going through Meta's verification process. There's no separate platform to learn depending on the number type — same agent, same dashboard, same inbox.
Conversational sales: catalog, checkout and follow-up in the chat
This is WhatsApp commerce, end to end: the agent answers catalog questions with real data from your connected store, walks the customer to checkout inside the conversation, and if the cart gets abandoned, fires an automatic follow-up to bring them back. None of that requires a human to be watching the chat in the moment — Steff answers 24/7.
Because it's the same agent handling support and sales, a customer who starts by asking about a return policy can end the same conversation buying a product, with no handoff to a different bot or a different number to make that happen.
Appointment booking on WhatsApp with Google Calendar
For service businesses, the agent can offer real availability, book, reschedule or cancel an appointment right inside the WhatsApp chat, synced to Google Calendar so the slot shows up on the team's calendar too. The customer never has to leave the conversation to book.
Pause the bot in 1 click, with human-echo detection
Any human agent can take over a conversation and reply directly, and heysteff automatically detects that manual reply ("echo" detection) to pause the bot on that conversation without anyone having to remember to switch it off. The pause can also be applied per channel, workspace-wide, or globally, and automatic escalation by rules and keywords covers the cases that should always reach a human.
heysteff vs. WATI, Respond.io and SleekFlow
WATI, Respond.io and SleekFlow are messaging platforms centered mainly on WhatsApp, with a strong focus on team inbox and flow automations. heysteff shares that foundation but adds a conversational multichannel AI agent (not just rules/flows), Shopify cart recovery, appointment booking synced to Google Calendar, and an MCP server so a client's own AI can configure the workspace. For the full picture, see their current pricing at heysteff vs. WATI, heysteff vs. Respond.io and heysteff vs. SleekFlow.
FAQ
Do I need a verified WhatsApp number?
No. heysteff supports the official WhatsApp Business Cloud API with a verified number (they help you apply for it, and it also accepts numbers from providers like Twilio or 360dialog), plus an unofficial number over Baileys for the number you already have, with no Meta verification required.
Can it sell, not just answer questions?
Yes. The agent talks through the catalog, helps close the sale by handing the customer a checkout link, follows up on abandoned Shopify carts, books appointments synced to Google Calendar, and can run outbound campaigns on the plans that include them.
What happens to my current WhatsApp number?
If you already have a number running, you can connect it as an unofficial number over Baileys without losing it, or migrate it to the official Cloud API if you prefer Meta verification. Either way, the bot pauses itself automatically the moment a human on your team replies manually, so it never overwrites that response.
How many WhatsApp numbers can I connect?
It depends on the plan: total connected channels (WhatsApp, Instagram, Messenger and Gmail combined) go from 2 on Starter, to 4 on Pro, to unlimited channels on Max.
Also relevant: AI agent for ecommerce, AI agent for Shopify, AI customer support, appointment scheduling and heysteff vs. other tools.