Telegram vs WhatsApp vs Slack vs Discord for working with AI agents

If you want to work with AI agents from a chat app, the choice between Telegram, WhatsApp, Slack and Discord matters less for the AI and more for the people. Pick the app your team will actually open, then check that it handles bots, files and group threads the way you need. Our short verdict: Telegram is the most capable for internal agent work; WhatsApp is the easiest to adopt but the most restricted for automation; Slack is the right answer if your team already lives in it at desks; Discord is a strong fit for communities and technical teams.

This comparison is current as of November 2026 and based on each platform’s own documentation, linked throughout. Platform rules change, so check the linked pages before you commit. It is part of our series on running your business from chat.

Telegram vs WhatsApp vs Slack vs Discord at a glance

Sources: Telegram FAQ and bot features; WhatsApp’s 1,024-participant limit as reported by 9to5Google; WhatsApp privacy page and terms of service; Slack pricing; Discord gateway documentation and encryption announcement.

Telegram: the most flexible for internal agent work

Telegram was built with bots in mind, and it shows. A bot can sit in a private chat with you or in a group with your team. Groups can be split into topics, each with its own history, media and notification settings, which maps neatly onto areas of work: Rentals, Accounts, Sales. Groups can hold up to 200,000 members, so size is never the constraint for a small business.

Two details matter for agents. First, privacy mode: Telegram enables it by default for bots in groups, so a bot sees only messages addressed to it, commands and replies to its own messages — unless it is made a group admin, in which case it receives all messages. That is a good default for mixed groups. Second, files: the standard Bot API lets a bot download files up to 20 MB and upload up to 50 MB, while a self-hosted Bot API server raises those limits. Long phone videos can exceed 20 MB, so ask how your provider handles them.

The trade-off is privacy. Telegram’s FAQ says cloud chats, including groups, use server-client encryption, with end-to-end encryption reserved for secret chats. For internal operations that is a reasonable trade for features, but it is a reason to keep sensitive client details in the client file, not in chat. Full set-up steps are in setting up a Telegram AI assistant.

WhatsApp: everyone has it, and the rules are strict

WhatsApp’s advantage is adoption. Your staff, subcontractors and many of your customers already use it, and personal messages and calls are end-to-end encrypted. Groups can have up to 1,024 participants. For a trades business or a small practice, “no new app” is a real benefit.

The constraint is automation. WhatsApp’s terms of service prohibit bulk messaging, auto-messaging and non-personal use of the service unless authorised, so connecting an AI agent to a personal WhatsApp account is the wrong approach. Businesses use either the WhatsApp Business app, built for small business owners chatting from a phone with features such as greeting and away messages, or the WhatsApp Business Platform, which is the API route for automation.

The Business Platform has its own rules. Since 1 July 2025 Meta charges per message; when a customer messages you, a 24-hour customer service window opens in which you can send normal replies, and outside that window you can only send pre-approved template messages (Meta pricing documentation). And from 15 January 2026 Meta’s Business Solution terms barred providers of general-purpose AI assistants from the platform, while businesses using AI to serve their own customers are not affected, according to TechCrunch.

We go through the Business app versus Business Platform decision, and internal versus customer-facing use, in using WhatsApp with an AI assistant.

Slack: right if your team already works at desks

Slack is a workspace rather than a messaging app: channels, threads, huddles and a large app directory, controlled by the business. If your team is five or more people on laptops and already uses Slack, put the agents there. Adding a second chat app for agent work just splits the record.

Mind the plan limits. On Slack’s free plan, messages are searchable for 90 days, you can connect up to 10 apps and integrations, and huddles and Slack Connect are one-to-one only, according to Slack’s pricing page. As of November 2026, the Australian pricing page lists Pro at US$8.75 per user per month paid monthly (US$7.25 paid annually) and Business+ at US$18 per user per month monthly (US$15 annually), shown in US dollars; check the current pricing because offers change.

Slack is a weaker fit for owner-operators who are mostly on the road, and for crews who won’t install a work app on their personal phones. It can do mobile perfectly well; people just tend not to treat it as the place they check.

Discord: strong for communities and technical teams

Discord organises people into servers with many channels, including threads and forum-style channels, and has a mature bot ecosystem. It is a natural home for businesses that already run a community there — creators, education, gaming-adjacent and software teams — and for technical teams who like its structure.

For agents, the key detail is that reading message content is a privileged intent. Without it, a bot receives empty content for most messages, except direct messages to the bot, messages that mention it and messages it sent itself. Apps with fewer than 10,000 users can enable privileged intents in the Developer Portal, and larger apps go through a review, per Discord’s documentation. On privacy, Discord made voice and video calls end-to-end encrypted by default (completed in March 2026) and has said it has no current plans to extend that to text messages.

Discord is a poor fit for most traditional small businesses simply because staff and clients don’t use it. If your team has never opened it, don’t start here.

Which channel suits which business

One opinion we hold firmly: choose one channel for internal agent work, even if customers reach you on several. Spreading instructions across WhatsApp, Slack and email means no single thread holds the full story. If you need several, keep the systems of record — CRM, files, accounts — outside chat, so every channel talks to the same history.

Customer-facing messaging is a different decision

Everything above is about where you and your team work with agents. Where you talk to customers is a separate question with separate rules. Customer messaging on WhatsApp generally means the Business Platform and its template and window rules. In Australia, commercial electronic messages — the ACMA lists email, SMS and instant messages — also fall under the Spam Act 2003, which generally requires consent, sender identification and a way to unsubscribe; see the ACMA’s guidance on avoiding sending spam. This is general information, not legal advice.

Our recommendation for most small businesses: agents draft customer messages, a person approves them, and they go out through the channel and number the customer already knows. For calls and SMS at volume, a dedicated voice platform is a better fit than a chat app; see AI voice agents in Australia.

Questions to settle before you choose

1. Will every person who needs to approve or act actually open this app daily?
2. Do you need separate threads per area of work inside one group?
3. Will you send long phone videos or large files to the agent?
4. Who owns the account or workspace if a staff member leaves?
5. Does anyone need to talk to customers through it, and under which platform rules?
6. What happens to your records if the platform changes its terms?

If you are mixing people and agents in the same group, the roles and permissions questions are covered in AI agents in group chats. Cortex works with all four apps; the channels page shows how instructions, approvals and reports appear in each.