Bot Development for Messenger Platforms: WhatsApp, Telegram and Signal (2025 guide)

This article is the result of research I conducted between April and June 2025.

While AI-powered chatbots grab headlines, interesting use cases lie in purpose-built messenger bots that solve specific problems: moderating chaotic group chats, converting files on-the-go or sending home automation notifications. Messenger bots have the advantage that they integrate into a platform that users are already familiar with.

As a developer, you’ve probably wondered: “Which platform should I build for?” The answer depends on the many factors: if its a hobby or a professional project, which messenger your users are already using, the features you want to implement, your budget, etc. In this article we’re going to focus on technical and legal aspects and here’s the tldr:

1️⃣ — Telegram is heaven for developers providing free APIs and extensive UI features

2️⃣ — WhatsApp dominates user numbers but locks you into business accounts and paid APIs

3️⃣ — Signal stays true to privacy principles but offers no official bot support or API

Each platform has evolved its own rules, tools, and quirks. What’s perfectly legal on Telegram might get you banned on WhatsApp. What works seamlessly in Telegram…