WhatsApp, Instagram or email: which channel to automate

On WhatsApp, a customer's message opens a 24-hour window for free-form replies. Anything you send outside it, and any conversation you start, needs a template approved by Meta, and the person must have opted in to hear from you. Meta charges for each message by category and by the recipient's country, and since 1 October 2026 it charges for service replies inside the window too, after the first 1,000 each month for every business number. In return, WhatsApp is where Slide runs template broadcasts, Shopify order updates and timed follow-ups to a phone number.

On Instagram, a business can only answer. Meta allows replies within 24 hours of the person's last message and one private reply to each comment within 7 days. Slide sends no broadcasts and no messages after the window, and story mentions are not a trigger. That makes Instagram a front door: comment-to-DM, story replies and quick questions that move a conversation forward while the person is still engaged.

Email has no reply window. Slide sends from your own authenticated domain through sequences and campaigns, which carry an unsubscribe and skip addresses that have unsubscribed or bounced, and each send draws on your plan's email credits. The automation "send email" step is the exception: it adds no unsubscribe link and does not check the unsubscribe list, so keep it for transactional mail and send marketing through sequences and campaigns.

The law differs by channel and by market as well. WhatsApp requires opt-in before you message someone first, several markets have rules that reach Instagram direct messages, and several countries set rules aimed at marketing email. The locations pages set out what applies where.

Every channel writes to the same contact. A person who comments on Instagram, messages on WhatsApp and opens an email is one record, matched on phone number first and email second, with the same tags, segments, custom fields and lifecycle stage. Contacts can be imported; there is no contacts export today.

Automations for all three channels are built in one builder with 41 trigger types: WhatsApp and Instagram messages, Shopify and HubSpot events, Google Sheets and Forms, Meta and Google lead forms, website forms, contact changes, webhooks and schedules. Conditions, routers, delays and wait-until steps (a fixed date and time) work the same whatever started the run, and every run is logged step by step.

Published setups show the pattern. Mirza International runs its flows across six channels on one contact record, and Newport moves interest from Instagram comments into DMs and then into WhatsApp for longer conversations. Both case studies describe the setup, not measured results.

Every channel runs on the same Slide plan. A workspace created with an Indian number is billed in rupees and every other workspace in US dollars; plans and current prices are on the pricing page, paid plans start with a 14-day trial, and AI steps depend on the plan. Outside India, confirm the payment method with the Slide team before you subscribe.

Usage differs by channel. WhatsApp messages are charged by Meta, per message, and drawn from Slide's prepaid wallet; since 1 October 2026 service replies count too, after 1,000 free each month per business number. Email sends draw on the email credits that come with the plan, and a sequence pauses when they run out. Meta's per-message pricing is a WhatsApp Business Platform rule, so Instagram replies add no per-message wallet charge.